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Cai Z, Luo W, Wang H, Zhu R, Yuan Y, Zhan X, Xie M, Zhuang H, Chen H, Xu Y, Li X, Liu L, Xu G. MFN2 suppresses the accumulation of lipid droplets and the progression of clear cell renal cell carcinoma. Cancer Sci 2024; 115:1791-1807. [PMID: 38480904 PMCID: PMC11145141 DOI: 10.1111/cas.16151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 02/12/2024] [Accepted: 02/26/2024] [Indexed: 06/04/2024] Open
Abstract
Dissolving the lipid droplets in tissue section with alcohol during a hematoxylin and eosin (H&E) stain causes the tumor cells to appear like clear soap bubbles under a microscope, which is a key pathological feature of clear cell renal cell carcinoma (ccRCC). Mitochondrial dynamics have been reported to be closely associated with lipid metabolism and tumor development. However, the relationship between mitochondrial dynamics and lipid metabolism reprogramming in ccRCC remains to be further explored. We conducted bioinformatics analysis to identify key genes regulating mitochondrial dynamics differentially expressed between tumor and normal tissues and immunohistochemistry and Western blot to confirm. After the target was identified, we created stable ccRCC cell lines to test the impact of the target gene on mitochondrial morphology, tumorigenesis in culture cells and xenograft models, and profiles of lipid metabolism. It was found that mitofusin 2 (MFN2) was downregulated in ccRCC tissues and associated with poor prognosis in patients with ccRCC. MFN2 suppressed mitochondrial fragmentation, proliferation, migration, and invasion of ccRCC cells and growth of xenograft tumors. Furthermore, MFN2 impacted lipid metabolism and reduced the accumulation of lipid droplets in ccRCC cells. MFN2 suppressed disease progression and improved prognosis for patients with ccRCC possibly by interrupting cellular lipid metabolism and reducing accumulation of lipid droplets.
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Affiliation(s)
- Zhiduan Cai
- Department of Urology, Key Laboratory of Biological Targeting DiagnosisTherapy and Rehabilitation of Guangdong Higher Education Institutes, The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical UniversityGuangzhouChina
| | - Wenjun Luo
- Department of Urology, Key Laboratory of Biological Targeting DiagnosisTherapy and Rehabilitation of Guangdong Higher Education Institutes, The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical UniversityGuangzhouChina
| | - Haoran Wang
- Department of Urology, Key Laboratory of Biological Targeting DiagnosisTherapy and Rehabilitation of Guangdong Higher Education Institutes, The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical UniversityGuangzhouChina
- Guangzhou Medical UniversityGuangzhouChina
| | - Rui Zhu
- Department of Urology, Key Laboratory of Biological Targeting DiagnosisTherapy and Rehabilitation of Guangdong Higher Education Institutes, The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical UniversityGuangzhouChina
| | - Yaoji Yuan
- Department of Urology, Key Laboratory of Biological Targeting DiagnosisTherapy and Rehabilitation of Guangdong Higher Education Institutes, The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical UniversityGuangzhouChina
| | - Xiangyu Zhan
- Department of Urology, Key Laboratory of Biological Targeting DiagnosisTherapy and Rehabilitation of Guangdong Higher Education Institutes, The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical UniversityGuangzhouChina
| | | | - Haoquan Zhuang
- Department of Urology, Key Laboratory of Biological Targeting DiagnosisTherapy and Rehabilitation of Guangdong Higher Education Institutes, The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical UniversityGuangzhouChina
| | - Haoyu Chen
- Department of Urology, Key Laboratory of Biological Targeting DiagnosisTherapy and Rehabilitation of Guangdong Higher Education Institutes, The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical UniversityGuangzhouChina
| | - Yuyu Xu
- Department of Urology, Key Laboratory of Biological Targeting DiagnosisTherapy and Rehabilitation of Guangdong Higher Education Institutes, The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical UniversityGuangzhouChina
| | - Xiezhao Li
- Department of Urology, Key Laboratory of Biological Targeting DiagnosisTherapy and Rehabilitation of Guangdong Higher Education Institutes, The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical UniversityGuangzhouChina
| | - Leyuan Liu
- Department of Urology, Key Laboratory of Biological Targeting DiagnosisTherapy and Rehabilitation of Guangdong Higher Education Institutes, The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical UniversityGuangzhouChina
| | - Guibin Xu
- Department of Urology, Key Laboratory of Biological Targeting DiagnosisTherapy and Rehabilitation of Guangdong Higher Education Institutes, The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical UniversityGuangzhouChina
- Guangdong Provincial Key Laboratory of UrologyThe First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical UniversityGuangzhouChina
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Wang K, Li L, Jin J, An Y, Wang Z, Zhou S, Zhang J, Abuduaini B, Cheng C, Li N. Fatty acid synthase (Fasn) inhibits the expression levels of immune response genes via alteration of alternative splicing in islet cells. J Diabetes Complications 2022; 36:108159. [PMID: 35210136 DOI: 10.1016/j.jdiacomp.2022.108159] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 12/17/2021] [Accepted: 02/11/2022] [Indexed: 10/19/2022]
Abstract
BACKGROUND Increasing evidence has shown that fatty acid synthase (Fasn) is associated with diabetes mellitus (DM) and insulin resistance, however, it remains unclear how Fasn upregulation leads to dysregulation of energy homeostasis in islet cells. Consequently, uncovering the function of Fasn in islet cells. Consequently, uncovering the function of FASN in islet cells is immensely important for finding a treatment target. AIM In this study, we elucidated the biological function of Fasn on the target genes in a rat insulinoma INS-1 cell line. METHODS We created a Fasn overexpressing rat insulinoma cell line (Fasn-OE), and performed bulk RNA-sequencing (RNA-seq) experiments on Fasn-OE and INS-1 (control) cells. We first identified differentially expressed genes (DEGs) using Bioconductor package edgeR, and then discovered enriched gene ontology terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways using the KEGG Orthology Based Annotation System (KOBAS) 2.0 web server. Furthermore, we identified alternative splicing events (ASEs) and regulated alternative splicing events (RASEs) by applying the ABLas pipeline. The reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used for validation of selected differentially expressed genes (DEGs) and Fasn-regulated alternative splicing genes (RASGs). RESULTS In this study we found that Fasn overexpression led to significant changes of gene expression profiles, including downregulations of mRNA levels of immune related genes, including Bst2, Ddit3, Isg15, Mx2, Oas1a, Oasl, and RT1-S3 in INS-1 cell line. Furthermore, Fasn positively regulated the expression of transcription factors such as Fat1 and Ncl diabetes-related genes. Importantly, Fasn overexpression to result in alternative splicing events including in a metabolism-associated ATP binding protein mRNA Abcc5. In Gene Ontology analysis, the downregulated genes in Fasn-OE cells were mainly enriched in inflammatory response and innate immune response. In Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, the downregulated genes were mainly enriched in TNF signaling pathway and cytokine-mediated signaling pathways. CONCLUSIONS Our findings showed that upregulation of Fasn may play a critical role in islet cell immunmetabolism via modifications of immune/inflammatory related genes on transcription and alternative splicing level, which provide novel insights into characterizing the function of Fasn in islet cell immunity and for the development of chemo/immune therapies.
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Affiliation(s)
- Kunling Wang
- Department of Traditional Chinese Medicine, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang 830054, PR China
| | - Lin Li
- Department of Molecular Biology, Xinjiang Medical University, Urumqi, Xinjiang 830054, PR China
| | - Jing Jin
- Department of Traditional Chinese Medicine, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang 830054, PR China
| | - Yanli An
- Department of Traditional Chinese Medicine, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang 830054, PR China
| | - Zhongjuan Wang
- Department of Traditional Chinese Medicine, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang 830054, PR China
| | - Shiying Zhou
- Department of Traditional Chinese Medicine, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang 830054, PR China
| | - Jiyuan Zhang
- The First Clinical Institute of Xinjiang Medical University
| | - Buzukela Abuduaini
- Department of Intensive Care Unit, The First Affiliated Hospital of Xinjiang Medical University.
| | - Chao Cheng
- ABLife BioBigData Institute, Wuhan, Hubei, 430075, China
| | - Ning Li
- ABLife BioBigData Institute, Wuhan, Hubei, 430075, China
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Abstract
Legumes are an essential food source worldwide. Their high-quality proteins, complex carbohydrates, dietary fiber, and relatively low-fat content make these an important functional food. Known to possess a multitude of health benefits, legume consumption is associated with the prevention and treatment of cardiovascular diseases (CVD). Legume crude protein isolates and purified peptides possess many cardiopreventive properties. Here, we review selected economically valued legumes, their taxonomy and distribution, biochemical composition, and their protein components and the mechanism(s) of action associated with cardiovascular health. Most of the legume protein studies had shown upregulation of low-density lipoprotein (LDL) receptor leading to increased binding and uptake, in effect significantly reducing total lipid levels in the blood serum and liver. This is followed by decreased biosynthesis of cholesterol and fatty acids. To understand the relationship of identified genes from legume studies, we performed gene network analysis, pathway, and gene ontology (GO) enrichment. Results showed that the genes were functionally interrelated while enrichment and pathway analysis revealed involvement in lipid transport, fatty acid and triglyceride metabolic processes, and regulatory processes. This review is the first attempt to collate all known mechanisms of action of legume proteins associated with cardiovascular health. This also provides a snapshot of possible targets leading to systems-level approaches to further investigate the cardiometabolic potentials of legumes.
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Tanshinone IIA Downregulates Lipogenic Gene Expression and Attenuates Lipid Accumulation through the Modulation of LXRα/SREBP1 Pathway in HepG2 Cells. Biomedicines 2021; 9:biomedicines9030326. [PMID: 33806955 PMCID: PMC8004631 DOI: 10.3390/biomedicines9030326] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 03/21/2021] [Accepted: 03/21/2021] [Indexed: 12/12/2022] Open
Abstract
Abnormal and excessive accumulation of lipid droplets within hepatic cells is the main feature of steatosis and nonalcoholic fatty liver disease (NAFLD) or metabolic-associated fatty liver disease (MAFLD). Dysregulation of lipogenesis contributes to hepatic steatosis and plays an essential role in the pathological progress of MAFLD. Tanshinone IIA is a bioactive phytochemical isolated from Salvia miltiorrhiza Bunge and exhibits anti-inflammatory, antiatherosclerotic and antihyperlipidemic effects. In this study, we aimed to investigate the lipid-lowering effects of tanshinone IIA on the regulation of lipogenesis, lipid accumulation, and the underlying mechanisms in hepatic cells. We demonstrated that tanshinone IIA can significantly inhibit the gene expression involved in de novo lipogenesis including FASN, ACC1, and SCD1, in HepG2 and Huh 7 cells. Tanshinone IIA could increase phosphorylation of ACC1 protein in HepG2 cells. We further demonstrated that tanshinone IIA also could suppress the fatty-acid-induced lipogenesis and TG accumulation in HepG2 cells. Furthermore, tanshinone IIA markedly downregulated the mRNA and protein expression of SREBP1, an essential transcription factor regulating lipogenesis in hepatic cells. Moreover, we found that tanshinone IIA attenuated liver X receptor α (LXRα)-mediated lipogenic gene expression and lipid droplet accumulation, but did not change the levels of LXRα mRNA or protein in HepG2 cells. The molecular docking data predicted tanshinone IIA binding to the ligand-binding domain of LXRα, which may result in the attenuation of LXRα-induced transcriptional activation. Our findings support the supposition that tanshinone IIA possesses a lipid-modulating effect that suppresses lipogenesis and attenuates lipid accumulation by modulating the LXRα/SREBP1 pathway in hepatic cells. Tanshinone IIA can be potentially used as a supplement or drug for the prevention or treatment of MAFLD.
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Jeong YU, Park YJ. Ergosterol Peroxide from the Medicinal Mushroom Ganoderma lucidum Inhibits Differentiation and Lipid Accumulation of 3T3-L1 Adipocytes. Int J Mol Sci 2020; 21:ijms21020460. [PMID: 31936890 PMCID: PMC7014426 DOI: 10.3390/ijms21020460] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/05/2020] [Accepted: 01/08/2020] [Indexed: 12/15/2022] Open
Abstract
Ergosterol peroxide is a natural compound of the steroid family found in many fungi, and it possesses antioxidant, anti-inflammatory, anticancer and antiviral activities. The anti-obesity activity of several edible and medicinal mushrooms has been reported, but the effect of mushroom-derived ergosterol peroxide on obesity has not been studied. Therefore, we analyzed the effect of ergosterol peroxide on the inhibition of triglyceride synthesis at protein and mRNA levels and differentiation of 3T3-L1 adipocytes. Ergosterol peroxide inhibited lipid droplet synthesis of differentiated 3T3-L1 cells, expression of peroxisome proliferator-activated receptor gamma (PPARγ) and CCAT/enhancer-binding protein alpha (C/EBPα), the major transcription factors of differentiation, and also the expression of sterol regulatory element-binding protein-1c (SREBP-1c), which promotes the activity of PPARγ, resulting in inhibition of differentiation. It further inhibited the expression of fatty acid synthase (FAS), fatty acid translocase (FAT), and acetyl-coenzyme A carboxylase (ACC), which are lipogenic factors. In addition, it inhibited the phosphorylation of mitogen-activated protein kinases (MAPKs) involved in cell proliferation and activation of early differentiation transcription factors in the mitotic clonal expansion (MCE) stage. As a result, ergosterol peroxide significantly inhibited the synthesis of triglycerides and differentiation of 3T3-L1 cells, and is, therefore, a possibile prophylactic and therapeutic agent for obesity and related metabolic diseases.
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Affiliation(s)
- Yong-Un Jeong
- Department of Medicinal Bioscience, College of Biomedical and Health Science, Konkuk University, 268 Chungwon-daero, Chungju-si 27478, Korea;
| | - Young-Jin Park
- Department of Medicinal Bioscience, College of Biomedical and Health Science, Konkuk University, 268 Chungwon-daero, Chungju-si 27478, Korea;
- Research Institute for Biomedical & Health Science, Konkuk University, 268 Chungwon-daero, Chungju-si 27478, Korea
- Correspondence: ; Tel.: +82-43-840-3601
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Sato T, Watanabe Y, Nishimura Y, Inoue M, Morita A, Miura S. Acute fructose intake suppresses fasting-induced hepatic gluconeogenesis through the AKT-FoxO1 pathway. Biochem Biophys Rep 2019; 18:100638. [PMID: 31032430 PMCID: PMC6479072 DOI: 10.1016/j.bbrep.2019.100638] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 03/19/2019] [Accepted: 04/08/2019] [Indexed: 11/21/2022] Open
Abstract
Excessive intake of fructose increases lipogenesis in the liver, leading to hepatic lipid accumulation and development of fatty liver disease. Metabolic alterations in the liver due to fructose intake have been reported in many studies, but the effect of fructose administration on hepatic gluconeogenesis is not fully understood. The aim of this study was to evaluate the acute effects of fructose administration on fasting-induced hepatic gluconeogenesis. C57BL/6J mice were administered fructose solution after 14 h of fasting and plasma insulin, glucose, free fatty acids, and ketone bodies were analysed. We also measured phosphorylated AKT and forkhead box O (FoxO) 1 protein levels and gene expression related to gluconeogenesis in the liver. Furthermore, we measured glucose production from pyruvate after fructose administration. Glucose-administered mice were used as controls. Fructose administration enhanced phosphorylation of AKT in the liver, without increase of blood insulin levels. Blood free fatty acids and ketone bodies concentrations were as high as those in the fasting group after fructose administration, suggesting that insulin-induced inhibition of lipolysis did not occur in mice administered with fructose. Fructose also enhanced phosphorylation of FoxO1 and suppressed gluconeogenic gene expression, glucose-6-phosphatase activity, and glucose production from pyruvate. The present study suggests that acute fructose administration suppresses fasting-induced hepatic gluconeogenesis in an insulin-independent manner.
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Key Words
- AKT
- CREB, cAMP response element binding protein
- ChREBP, carbohydrate response element binding protein
- EDTA, ethylenediaminetetraacetic acid
- FFA, free fatty acid
- FoxO, forkhead box O
- FoxO1
- Fructose
- G6Pase
- G6Pase, glucose-6-phosphatase
- Gluconeogenesis
- Insulin
- PEPCK, phosphoenolpyruvate carboxykinase
- PGC-1α, peroxisome proliferator-activated receptor gamma coactivator-1 alpha
- PI3K, phosphoinositide-3-kinase
- PIP 3, phosphatidylinositol-(3,4,5)-trisphosphate
- SREBP, sterol-regulatory element binding protein
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Affiliation(s)
- Tomoki Sato
- Laboratory of Nutritional Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan
- Research Fellow of Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo, 102-0083, Japan
| | - Yui Watanabe
- Laboratory of Nutritional Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan
| | - Yuri Nishimura
- Laboratory of Nutritional Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan
| | - Mizuki Inoue
- Laboratory of Nutritional Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan
| | - Akihito Morita
- Laboratory of Nutritional Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan
| | - Shinji Miura
- Laboratory of Nutritional Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan
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Hong M, Hwang JT, Shin EJ, Hur HJ, Kang K, Choi HK, Chung MY, Chung S, Sung MJ, Park JH. Genome-wide analysis of DNA methylation identifies novel differentially methylated regions associated with lipid accumulation improved by ethanol extracts of Allium tubersosum and Capsella bursa-pastoris in a cell model. PLoS One 2019; 14:e0217877. [PMID: 31170227 PMCID: PMC6553759 DOI: 10.1371/journal.pone.0217877] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 05/20/2019] [Indexed: 02/06/2023] Open
Abstract
Hepatic steatosis is the most common chronic liver disease in Western countries. Both genetic and environmental factors are known as causes of the disease although their underlying mechanisms have not been fully understood. This study investigated the association of DNA methylation with oleic acid-induced hepatic steatosis. It also examined effects of food components on DNA methylation in hepatic steatosis. Genome-wide DNA methylation of oleic acid (OA)-induced lipid accumulation in vitro cell model was investigated using reduced representation bisulfite sequencing. Changes of DNA methylation were also analyzed after treatment with food components decreasing OA-induced lipid accumulation in the model. We identified total 81 regions that were hypermethylated by OA but hypomethylated by food components or vice versa. We determined the expression of seven genes proximally located at the selected differentially methylated regions. Expression levels of WDR27, GNAS, DOK7, MCF2L, PRKG1, and CMYA5 were significantly different between control vs OA and OA vs treatment with food components. We demonstrated that DNA methylation was associated with expression of genes in the model of hepatic steatosis. We also found that food components reversely changed DNA methylation induced by OA and alleviated lipid accumulation. These results suggest that DNA methylation is one of the mechanisms causing the hepatic steatosis and its regulation by food components provides insights that may prevent or alleviate lipid accumulation.
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Affiliation(s)
- Moonju Hong
- Division of Food Functionality, Korea Food Research Institute, Iseo-myeon, Wanju-gun, Republic of Korea
- Department of Food Biotechnology, University of Science & Technology, Daejeon, Republic of Korea
| | - Jin-Taek Hwang
- Division of Food Functionality, Korea Food Research Institute, Iseo-myeon, Wanju-gun, Republic of Korea
- Department of Food Biotechnology, University of Science & Technology, Daejeon, Republic of Korea
| | - Eun Ju Shin
- Division of Food Functionality, Korea Food Research Institute, Iseo-myeon, Wanju-gun, Republic of Korea
| | - Haeng Jeon Hur
- Division of Food Functionality, Korea Food Research Institute, Iseo-myeon, Wanju-gun, Republic of Korea
| | - Keunsoo Kang
- Department of Microbiology, College of Natural Sciences, Dankook University, Cheonan, Republic of Korea
| | - Hyo-Kyoung Choi
- Division of Food Functionality, Korea Food Research Institute, Iseo-myeon, Wanju-gun, Republic of Korea
| | - Min-Yu Chung
- Division of Food Functionality, Korea Food Research Institute, Iseo-myeon, Wanju-gun, Republic of Korea
| | - Sangwon Chung
- Division of Food Functionality, Korea Food Research Institute, Iseo-myeon, Wanju-gun, Republic of Korea
| | - Mi Jeong Sung
- Division of Food Functionality, Korea Food Research Institute, Iseo-myeon, Wanju-gun, Republic of Korea
| | - Jae-Ho Park
- Division of Food Functionality, Korea Food Research Institute, Iseo-myeon, Wanju-gun, Republic of Korea
- * E-mail:
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Schleicher J, Dahmen U, Guthke R, Schuster S. Zonation of hepatic fat accumulation: insights from mathematical modelling of nutrient gradients and fatty acid uptake. J R Soc Interface 2018; 14:rsif.2017.0443. [PMID: 28835543 DOI: 10.1098/rsif.2017.0443] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 07/28/2017] [Indexed: 02/07/2023] Open
Abstract
Intrinsic of non-alcoholic fatty liver diseases is an aberrant accumulation of triglycerides (steatosis), which occurs inhomogeneously within lobules. To improve our understanding of the mechanisms involved in this zonation patterning, we developed a mathematical multicompartment model of hepatic fatty acid metabolism accompanied by blood flow simulations. A model analysis determines the influence of the uptake process of fatty acids, the porto-central gradient of plasma fatty acid concentration, and the oxygen supply via blood on the zonation of triglyceride accumulation. From this theoretical perspective, the plasma oxygen gradient, but not the fatty acid gradient, leads the way to a zonated triglyceride accumulation by its decisive role in oxidative processes. In addition, the uptake mechanism of fatty acids seems to be fundamental for a pericentral dominance of steatosis. However, the mechanism of cellular fatty acid uptake from the blood is still under debate. Our theoretical approach supports the transporter-mediated uptake mechanism and reveals that the maximal velocity of fatty acid uptake affects the switching between a periportal and a pericentral triglyceride accumulation. Further research on hepatic fatty acid uptake is needed to push forward our understanding of aberrant triglyceride accumulation in diet-induced steatosis.
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Affiliation(s)
- Jana Schleicher
- Experimental Transplantation Surgery, Department of General, Visceral and Vascular Surgery, University Hospital Jena, Jena, Germany .,Department of Bioinformatics, Friedrich-Schiller-University Jena, Jena, Germany
| | - Uta Dahmen
- Experimental Transplantation Surgery, Department of General, Visceral and Vascular Surgery, University Hospital Jena, Jena, Germany
| | - Reinhard Guthke
- Leibniz Institute for Natural Product Research and Infection Biology - Hans Knoell Institute, Jena, Germany
| | - Stefan Schuster
- Department of Bioinformatics, Friedrich-Schiller-University Jena, Jena, Germany
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Proteomic evaluation of mouse adipose tissue and liver following hydroxytyrosol supplementation. Food Chem Toxicol 2017; 107:329-338. [DOI: 10.1016/j.fct.2017.07.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 07/03/2017] [Accepted: 07/04/2017] [Indexed: 12/16/2022]
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Antu KA, Riya MP, Nair A, Mishra A, Srivastava AK, Raghu KG. Symplocos cochinchinensis enhances insulin sensitivity via the down regulation of lipogenesis and insulin resistance in high energy diet rat model. JOURNAL OF ETHNOPHARMACOLOGY 2016; 193:500-509. [PMID: 27686268 DOI: 10.1016/j.jep.2016.09.050] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 09/25/2016] [Accepted: 09/25/2016] [Indexed: 06/06/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE This plant has been utilized in Indian system of medicine for treatment of diabetes. This is clearly evident from the composition of Ayurvedic preparation for diabetes 'Nisakathakadi Kashayam' where this is one of the main ingredients of this preparation AIM OF THE STUDY: The study aims in elucidating the molecular mechanisms underlying the insulin sensitizing effects of Symplocos cochinchinensis ethanol extract (SCE) using a high fructose and saturated fat (HFS) fed insulin resistant rat model. MATERIALS AND METHODS Experimental groups consisted of normal diet (ND), ND+SCE 500mg/kg bwd, HFS+vehicle, HFS+metformin 100mg/kg bwd, HFS+SCE 250/500mg/kg bwd. Initially the animals were kept under HFS diet for 8 weeks, and at the end of 8 week period, animals were found to develop insulin resistance and dyslipidemia. Post-administration of SCE, metformin or vehicle were carried out for 3 weeks. Gene and protein expressions relevant to insulin signalling pathway were analysed. RESULTS HFS significantly altered the normal physiology of animals via proteins and genes relevant to metabolism like stearoyl-CoA desaturase (SCD1), sterol regulatory element binding protein 1 (SREBP-1c), fatty acid synthase (FAS), glucose 6 phosphatase (G6Pase), phosphoenol pyruvate carboxykinase (PEPCK), glucose transporter 2 (GLUT2), protein tyrosine phosphatse 1B (PTP1B), peroxisome proliferator activated receptor alpha (PPAR alpha), sirtuin 1 (SIRT1) and glucokinase. SCE administration attenuates the insulin resistance in HFS rat by the down regulation of SCD1 gene expression that modulates SREBP-1c dependent and independent hepatic lipid accumulation. CONCLUSION SCE enhances insulin sensitivity via the down regulation of lipogenesis and insulin resistance in HFS rat model.
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Affiliation(s)
- Kalathookunnel Antony Antu
- Agroprocessing and Natural Products Division, CSIR - National Institute for Interdisciplinary Science and Technology(NIIST), Thiruvananthapuram 695019, Kerala, India
| | - Mariam Philip Riya
- Agroprocessing and Natural Products Division, CSIR - National Institute for Interdisciplinary Science and Technology(NIIST), Thiruvananthapuram 695019, Kerala, India
| | - Anupama Nair
- Agroprocessing and Natural Products Division, CSIR - National Institute for Interdisciplinary Science and Technology(NIIST), Thiruvananthapuram 695019, Kerala, India
| | - Arvind Mishra
- Division of Biochemistry, CSIR - Central Drug Research Institute(CDRI), Sector 10, Janakipuram Extension, Sitapur Road, Lucknow 226031, Uttar Pradesh, India
| | - Arvind K Srivastava
- Division of Biochemistry, CSIR - Central Drug Research Institute(CDRI), Sector 10, Janakipuram Extension, Sitapur Road, Lucknow 226031, Uttar Pradesh, India
| | - Kozhiparambil Gopalan Raghu
- Agroprocessing and Natural Products Division, CSIR - National Institute for Interdisciplinary Science and Technology(NIIST), Thiruvananthapuram 695019, Kerala, India.
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11
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Lin HP, Cheng ZL, He RY, Song L, Tian MX, Zhou LS, Groh BS, Liu WR, Ji MB, Ding C, Shi YH, Guan KL, Ye D, Xiong Y. Destabilization of Fatty Acid Synthase by Acetylation Inhibits De Novo Lipogenesis and Tumor Cell Growth. Cancer Res 2016; 76:6924-6936. [PMID: 27758890 DOI: 10.1158/0008-5472.can-16-1597] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 08/25/2016] [Accepted: 09/15/2016] [Indexed: 11/16/2022]
Abstract
Fatty acid synthase (FASN) is the terminal enzyme in de novo lipogenesis and plays a key role in cell proliferation. Pharmacologic inhibitors of FASN are being evaluated in clinical trials for treatment of cancer, obesity, and other diseases. Here, we report a previously unknown mechanism of FASN regulation involving its acetylation by KAT8 and its deacetylation by HDAC3. FASN acetylation promoted its degradation via the ubiquitin-proteasome pathway. FASN acetylation enhanced its association with the E3 ubiquitin ligase TRIM21. Acetylation destabilized FASN and resulted in decreased de novo lipogenesis and tumor cell growth. FASN acetylation was frequently reduced in human hepatocellular carcinoma samples, which correlated with increased HDAC3 expression and FASN protein levels. Our results suggest opportunities to target FASN acetylation as an anticancer strategy. Cancer Res; 76(23); 6924-36. ©2016 AACR.
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Affiliation(s)
- Huai-Peng Lin
- Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China.,Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, and Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China.,State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China
| | - Zhou-Li Cheng
- Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China.,Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, and Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China.,State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China
| | - Ruo-Yu He
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, China
| | - Lei Song
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Radiation Medicine, National Center for National Center for Protein Science (The PHOENIX Center), Beijing, China
| | - Meng-Xin Tian
- Department of Liver Surgery, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, China.,Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education, Shanghai, China
| | - Li-Sha Zhou
- Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China.,Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, and Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China.,State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China
| | - Beezly S Groh
- Department of Biochemistry and Biophysics, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Wei-Ren Liu
- Department of Liver Surgery, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, China.,Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education, Shanghai, China
| | - Min-Biao Ji
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, China
| | - Chen Ding
- Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China.,Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, and Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China.,State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China.,State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Radiation Medicine, National Center for National Center for Protein Science (The PHOENIX Center), Beijing, China
| | - Ying-Hong Shi
- Department of Liver Surgery, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, China.,Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education, Shanghai, China
| | - Kun-Liang Guan
- Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China. .,Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, and Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China.,State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China.,Department of Pharmacology and Moores Cancer Center, University of California San Diego, La Jolla, California
| | - Dan Ye
- Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China. .,Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, and Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China.,State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China.,Department of General Surgery, Huashan Hospital, Fudan University, Shanghai, China
| | - Yue Xiong
- Molecular and Cell Biology Lab, Institute of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China. .,Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, and Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China.,State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China.,Department of Biochemistry and Biophysics, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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12
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Herman MA, Samuel VT. The Sweet Path to Metabolic Demise: Fructose and Lipid Synthesis. Trends Endocrinol Metab 2016; 27:719-730. [PMID: 27387598 PMCID: PMC5035631 DOI: 10.1016/j.tem.2016.06.005] [Citation(s) in RCA: 145] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 06/06/2016] [Accepted: 06/09/2016] [Indexed: 01/04/2023]
Abstract
Epidemiological studies link fructose consumption with metabolic disease, an association attributable in part to fructose-mediated lipogenesis. The mechanisms governing fructose-induced lipogenesis and disease remain debated. Acutely, fructose increases de novo lipogenesis through the efficient and uninhibited action of ketohexokinase and aldolase B which yields substrates for fatty-acid synthesis. Chronic fructose consumption further enhances the capacity for hepatic fructose metabolism by activating several key transcription factors (i.e., SREBP1c and ChREBP) which augment the expression of lipogenic enzymes, increasing lipogenesis and further compounding hypertriglyceridemia and hepatic steatosis. Hepatic insulin resistance develops from diacylglycerol-PKCɛ-mediated impairment of insulin signaling and possibly additional mechanisms. Initiatives that decrease fructose consumption and therapies that block fructose-mediated lipogenesis will be necessary to avert future metabolic pandemics.
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Affiliation(s)
- Mark A Herman
- Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA.
| | - Varman T Samuel
- Yale University School of Medicine, 950 Campbell Avenue, West Haven, CT 06516, USA; Veterans Affairs Connecticut Healthcare System, 950 Campbell Avenue, West Haven, CT 06516, USA.
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13
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Suzuki T, Muramatsu T, Morioka K, Goda T, Mochizuki K. ChREBP binding and histone modifications modulate hepatic expression of the Fasn gene in a metabolic syndrome rat model. Nutrition 2015; 31:877-83. [PMID: 25933497 DOI: 10.1016/j.nut.2015.01.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 12/25/2014] [Accepted: 01/14/2015] [Indexed: 11/17/2022]
Abstract
OBJECTIVE Although the expression of hepatic lipogenic genes is enhanced in insulin resistance, the underlying mechanism is unclear. To reveal the details, the aim of this study was to investigate whether the expression of hepatic lipogenic genes are mediated by epigenetic regulation and specific transcription factors in an insulin resistance model of rats. METHODS Using a rat model of insulin resistance (SHR/NDmc-cp), we investigated the relationship between hepatic expression of the lipogenic gene fatty-acid synthase (Fasn), binding of the transcription factor carbohydrate-responsive element-binding protein (ChREBP) to the Fasn gene, and histone modifications in the region of the Fasn gene by real-time reverse transcriptase polymerase chain reaction, immunoblotting, and chromatin immunoprecipitation assay. RESULTS Compared with control rats, Fasn mRNA expression and protein levels were higher in the livers of SHR/NDmc-cp rats, as were protein expression levels and Fasn binding of ChREBP and RNA polymerase II. Moreover, compared with the livers of control rats, levels of mono-methylated histone H3 lysine (K) 4 and acetylated histone H4 were higher in the promoter/enhancer region of the Fasn gene in the livers of SHR/NDmc-cp rats. Levels of trimethylated histone H3K4 and acetylated histone H3 were higher in the transcribed region. CONCLUSION The results of this study indicate that expression of the Fasn gene in the livers of insulin-resistant rats is associated with increased H3K4 methylation, increased histone H3 acetylation, and increased H4 acetylation, and also, binding levels of ChREBP to promoter/enhancer region of Fasn gene is involved in the Fasn gene expression caused by hyperglycemia.
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Affiliation(s)
- Takuji Suzuki
- Laboratory of Nutritional Physiology, Graduate School of Nutritional and Environmental Sciences, Global COE Program, University of Shizuoka, Shizuoka, Japan; Food Environmental Design Course, Faculty of Education, Art and Science, Yamagata University, Yamagata, Japan
| | - Takeshi Muramatsu
- Laboratory of Nutritional Physiology, Graduate School of Nutritional and Environmental Sciences, Global COE Program, University of Shizuoka, Shizuoka, Japan
| | - Kousuke Morioka
- Laboratory of Nutritional Physiology, Graduate School of Nutritional and Environmental Sciences, Global COE Program, University of Shizuoka, Shizuoka, Japan
| | - Toshinao Goda
- Laboratory of Nutritional Physiology, Graduate School of Nutritional and Environmental Sciences, Global COE Program, University of Shizuoka, Shizuoka, Japan
| | - Kazuki Mochizuki
- Laboratory of Nutritional Physiology, Graduate School of Nutritional and Environmental Sciences, Global COE Program, University of Shizuoka, Shizuoka, Japan; Laboratory of Food and Nutritional Sciences, Faculty of Life and Environmental Sciences, University of Yamanashi, Yamanashi, Japan.
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14
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Iritani N, Hirakawa T, Fukuda H, Katsukawa M, Kouno M. Comparison of labeled acetate and glucose incorporations into lipids in the liver and adipose tissue after intravenous injection in rats. J Nutr Sci Vitaminol (Tokyo) 2014; 60:176-82. [PMID: 25078373 DOI: 10.3177/jnsv.60.176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
To compare incorporations of acetate and glucose in tissue total lipids and triacylglycerols (TAG), incorporations of labeled acetate and glucose in livers and epididymal adipose tissues (adipose tissue) were followed after their intravenous injection in the tail vein of individual rat fed a fat-free or 10% corn oil diet. The incorporation of acetate into total lipids (mostly TAG) in the liver reached maximum 2 h after the injection, while the incorporation of glucose decreased more quickly. Incorporation of glucose into total lipids and TAG was more greatly suppressed by dietary corn oil than that of acetate in the liver. In the adipose tissues, the incorporation of labeled acetate or glucose into total lipids was maximum 2-8 h after the injection, while the incorporation of glucose was very low, especially in rats fed the corn oil diet. Moreover, the time courses for labeled acetate and glucose incorporations into total lipids in the liver were parallel to those in plasma, but opposite to those in adipose tissue. TAG synthesized from acetate and glucose in the liver appeared to be mostly transported to adipose tissue. Thus, it is suggested that as the labeled glucose rapidly decreased in the liver, plasma and adipose tissue, TAG should be less derived from dietary carbohydrate than from dietary fat.
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15
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Effect of fructose on postprandial triglycerides: a systematic review and meta-analysis of controlled feeding trials. Atherosclerosis 2013; 232:125-33. [PMID: 24401226 DOI: 10.1016/j.atherosclerosis.2013.10.019] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 10/09/2013] [Accepted: 10/22/2013] [Indexed: 12/18/2022]
Abstract
BACKGROUND In the absence of consistent clinical evidence, concerns have been raised that fructose raises postprandial triglycerides. PURPOSE A systematic review and meta-analysis was conducted to assess the effect of fructose on postprandial triglycerides. DATA SOURCES Relevant studies were identified from MEDLINE, EMBASE, and Cochrane databases (through September 3, 2013). DATA SELECTION Relevant clinical trials of ≥ 7-days were included in the analysis. DATA EXTRACTION Two independent reviewers extracted relevant data with disagreements reconciled by consensus. The Heyland Methodological Quality Score (MQS) assessed study quality. Data were pooled by the generic inverse variance method using random effects models and expressed as standardized mean differences (SMD) with 95% confidence intervals (CI). Heterogeneity was assessed (Cochran Q statistic) and quantified (I(2) statistic). DATA SYNTHESIS Eligibility criteria were met by 14 isocaloric trials (n = 290), in which fructose was exchanged isocalorically for other carbohydrate in the diet, and two hypercaloric trials (n = 33), in which fructose supplemented the background diet with excess energy from high-dose fructose compared with the background diet alone (without the excess energy). There was no significant effect in the isocaloric trials (SMD: 0.14 [95% CI: -0.02, 0.30]) with evidence of considerable heterogeneity explained by a single trial. Hypercaloric trials, however, showed a significant postprandial triglyceride raising-effect of fructose (SMD: 0.65 [95% CI: 0.30, 1.01]). LIMITATIONS Most of the available trials were small, short, and of poor quality. Interpretation of the isocaloric trials is complicated by the large influence of a single trial. CONCLUSIONS Pooled analyses show that fructose in isocaloric exchange for other carbohydrate does not increase postprandial triglycerides, although an effect cannot be excluded under all conditions. Fructose providing excess energy does increase postprandial triglycerides. Larger, longer, and higher-quality trials are needed. PROTOCOL REGISTRATION ClinicalTrials.gov identifier, NCT01363791.
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16
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Brooks ED, Little D, Arumugam R, Sun B, Curtis S, DeMaster A, Maranzano M, Jackson MW, Kishnani P, Freemark MS, Koeberl DD. Pathogenesis of growth failure and partial reversal with gene therapy in murine and canine Glycogen Storage Disease type Ia. Mol Genet Metab 2013; 109:161-70. [PMID: 23623482 PMCID: PMC3764490 DOI: 10.1016/j.ymgme.2013.03.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Revised: 03/29/2013] [Accepted: 03/29/2013] [Indexed: 12/17/2022]
Abstract
Glycogen Storage Disease type Ia (GSD-Ia) in humans frequently causes delayed bone maturation, decrease in final adult height, and decreased growth velocity. This study evaluates the pathogenesis of growth failure and the effect of gene therapy on growth in GSD-Ia affected dogs and mice. Here we found that homozygous G6pase (-/-) mice with GSD-Ia have normal growth hormone (GH) levels in response to hypoglycemia, decreased insulin-like growth factor (IGF) 1 levels, and attenuated weight gain following administration of GH. Expression of hepatic GH receptor and IGF 1 mRNAs and hepatic STAT5 (phospho Y694) protein levels are reduced prior to and after GH administration, indicating GH resistance. However, restoration of G6Pase expression in the liver by treatment with adeno-associated virus 8 pseudotyped vector expressing G6Pase (AAV2/8-G6Pase) corrected body weight, but failed to normalize plasma IGF 1 in G6pase (-/-) mice. Untreated G6pase (-/-) mice also demonstrated severe delay of growth plate ossification at 12 days of age; those treated with AAV2/8-G6Pase at 14 days of age demonstrated skeletal dysplasia and limb shortening when analyzed radiographically at 6 months of age, in spite of apparent metabolic correction. Moreover, gene therapy with AAV2/9-G6Pase only partially corrected growth in GSD-Ia affected dogs as detected by weight and bone measurements and serum IGF 1 concentrations were persistently low in treated dogs. We also found that heterozygous GSD-Ia carrier dogs had decreased serum IGF 1, adult body weights and bone dimensions compared to wild-type littermates. In sum, these findings suggest that growth failure in GSD-Ia results, at least in part, from hepatic GH resistance. In addition, gene therapy improved growth in addition to promoting long-term survival in dogs and mice with GSD-Ia.
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Affiliation(s)
- Elizabeth Drake Brooks
- Division of Medical Genetics, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
- Division of Laboratory Animal Resources, Duke University Medical Center, Durham, NC, USA
| | - Dianne Little
- Orthopaedic Research Laboratories, Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA
| | - Ramamani Arumugam
- Division of Endocrinology and Diabetes, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
| | - Baodong Sun
- Division of Medical Genetics, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
| | - Sarah Curtis
- Division of Medical Genetics, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
- Division of Laboratory Animal Resources, Duke University Medical Center, Durham, NC, USA
| | - Amanda DeMaster
- Division of Medical Genetics, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
- Division of Laboratory Animal Resources, Duke University Medical Center, Durham, NC, USA
| | - Michael Maranzano
- Division of Medical Genetics, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
| | - Mark W. Jackson
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Scotland, UK
| | - Priya Kishnani
- Division of Medical Genetics, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
| | - Michael S. Freemark
- Division of Endocrinology and Diabetes, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
| | - Dwight D. Koeberl
- Division of Medical Genetics, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
- Corresponding author at: DUMC Box 103856, Duke University Medical Center, Durham, NC 27710, USA. Fax: +1 919684 0983. (D.D. Koeberl)
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Crystal structure of FAS thioesterase domain with polyunsaturated fatty acyl adduct and inhibition by dihomo-gamma-linolenic acid. Proc Natl Acad Sci U S A 2011; 108:15757-62. [PMID: 21908709 DOI: 10.1073/pnas.1112334108] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Human fatty acid synthase (hFAS) is a homodimeric multidomain enzyme that catalyzes a series of reactions leading to the de novo biosynthesis of long-chain fatty acids, mainly palmitate. The carboxy-terminal thioesterase (TE) domain determines the length of the fatty acyl chain and its ultimate release by hydrolysis. Because of the upregulation of hFAS in a variety of cancers, it is a target for antiproliferative agent development. Dietary long-chain polyunsaturated fatty acids (PUFAs) have been known to confer beneficial effects on many diseases and health conditions, including cancers, inflammations, diabetes, and heart diseases, but the precise molecular mechanisms involved have not been elucidated. We report the 1.48 Å crystal structure of the hFAS TE domain covalently modified and inactivated by methyl γ-linolenylfluorophosphonate. Whereas the structure confirmed the phosphorylation by the phosphonate head group of the active site serine, it also unexpectedly revealed the binding of the 18-carbon polyunsaturated γ-linolenyl tail in a long groove-tunnel site, which itself is formed mainly by the emergence of an α helix (the "helix flap"). We then found inhibition of the TE domain activity by the PUFA dihomo-γ-linolenic acid; γ- and α-linolenic acids, two popular dietary PUFAs, were less effective. Dihomo-γ-linolenic acid also inhibited fatty acid biosynthesis in 3T3-L1 preadipocytes and selective human breast cancer cell lines, including SKBR3 and MDAMB231. In addition to revealing a novel mechanism for the molecular recognition of a polyunsaturated fatty acyl chain, our results offer a new framework for developing potent FAS inhibitors as therapeutics against cancers and other diseases.
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Resveratrol attenuates steatosis in obese Zucker rats by decreasing fatty acid availability and reducing oxidative stress. Br J Nutr 2011; 107:202-10. [PMID: 21733326 DOI: 10.1017/s0007114511002753] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Non-alcoholic fatty liver disease (NAFLD) is one of the most common manifestations of chronic liver disease worldwide. The aim of the present study was to assess the effect of resveratrol on liver fat accumulation, as well as on the activity of those enzymes involved in lipogenesis and fatty acid oxidation in fa/fa Zucker rats. A total of thirty rats were assigned to three experimental groups and orally treated with resveratrol for 6 weeks, or without resveratrol (C: control group; RSV15 group: 15 mg/kg body weight per d; RSV45 group: 45 mg/kg body weight per d). Liver histological analysis was performed by microscopy. Levels of hepatic carnitine palmitoyltransferase-Ia (CPT-Ia), acyl-coenzyme A oxidase (ACO), fatty acid synthase, glucose-6-phosphate dehydrogenase and malic enzyme were assessed by spectrophotometry, and acetyl-CoA carboxylase was assessed by radiometry. Commercial kits were used to determine serum TAG, NEFA, total HDL and non-HDL-cholesterol, glycerol, ketonic bodies, glucose, insulin, adiponectin, aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP), hepatic TAG, thiobarbituric acid reactive substrates, GSH (GSSG) and superoxide dismutase. Resveratrol reduced liver weight and TAG content. It did not modify the activity of lipogenic enzymes but it did increase CPT-Ia and ACO activities. NEFA and ALP were reduced in both resveratrol-treated groups. AST/GOT was reduced only by the lowest dose. ALT/GPT, TAG and adiponectin remained unchanged. Resveratrol reduced liver oxidative stress. This study demonstrates that resveratrol can protect the liver from NAFLD by reducing fatty acid availability. Moreover, resveratrol also protects liver from oxidative stress.
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Alberdi G, Rodríguez VM, Miranda J, Macarulla MT, Arias N, Andrés-Lacueva C, Portillo MP. Changes in white adipose tissue metabolism induced by resveratrol in rats. Nutr Metab (Lond) 2011; 8:29. [PMID: 21569266 PMCID: PMC3101135 DOI: 10.1186/1743-7075-8-29] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Accepted: 05/10/2011] [Indexed: 01/04/2023] Open
Abstract
Background A remarkable range of biological functions have been ascribed to resveratrol. Recently, this polyphenol has been shown to have body fat lowering effects. The aim of the present study was to assess some of the potential underlying mechanisms of action which take place in adipose tissue. Methods Sixteen male Sprague-Dawley rats were randomly divided into two groups: control and treated with 30 mg resveratrol/kg body weight/d. All rats were fed an obesogenic diet and after six weeks of treatment white adipose tissues were dissected. Lipoprotein lipase activity was assessed by fluorimetry, acetyl-CoA carboxylase by radiometry, and malic enzyme, glucose-6P-dehydrogenase and fatty acid synthase by spectrophotometry. Gene expression levels of acetyl-CoA carboxylase, fatty acid synthase, lipoprotein lipase, hormone-sensitive lipase, adipose triglyceride lipase, PPAR-gamma, SREBP-1c and perilipin were assessed by Real time RT-PCR. The amount of resveratrol metabolites in adipose tissue was measured by chromatography. Results There was no difference in the final body weight of the rats; however, adipose tissues were significantly decreased in the resveratrol-treated group. Resveratrol reduced the activity of lipogenic enzymes, as well as that of heparin-releasable lipoprotein lipase. Moreover, a significant reduction was induced by this polyphenol in hormone-sensitive lipase mRNA levels. No significant changes were observed in other genes. Total amount of resveratrol metabolites in adipose tissue was 2.66 ± 0.55 nmol/g tissue. Conclusions It can be proposed that the body fat-lowering effect of resveratrol is mediated, at least in part, by a reduction in fatty acid uptake from circulating triacylglycerols and also in de novo lipogenesis.
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Affiliation(s)
- Goiuri Alberdi
- Department of Nutrition and Food Science, Faculty of Pharmacy, University of País Vasco, Paseo de la Universidad 7, 01006 Vitoria, Spain.
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Reddy SS, Ramatholisamma P, Karuna R, Saralakumari D. Preventive effect of Tinospora cordifolia against high-fructose diet-induced insulin resistance and oxidative stress in male Wistar rats. Food Chem Toxicol 2009; 47:2224-9. [DOI: 10.1016/j.fct.2009.06.008] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2009] [Revised: 04/27/2009] [Accepted: 06/05/2009] [Indexed: 11/28/2022]
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Sun B, Li S, Yang L, Damodaran T, Desai D, Diehl AM, Alzate O, Koeberl DD. Activation of glycolysis and apoptosis in glycogen storage disease type Ia. Mol Genet Metab 2009; 97:267-71. [PMID: 19419892 DOI: 10.1016/j.ymgme.2009.04.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Accepted: 04/02/2009] [Indexed: 10/20/2022]
Abstract
The deficiency of glucose-6-phosphatase (G6Pase) underlies glycogen storage disease type Ia (GSD-Ia, von Gierke disease; MIM 232200), an autosomal recessive disorder of metabolism associated with life-threatening hypoglycemia, growth retardation, renal failure, hepatic adenomas, and hepatocellular carcinoma. Liver involvement includes the massive accumulation of glycogen and lipids due to accumulated glucose-6-phosphate and glycolytic intermediates. Proteomic analysis revealed elevations in glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and other enzymes involved in glycolysis. GAPDH was markedly increased in murine G6Pase-deficient hepatocytes. The moonlighting role of GAPDH includes increasing apoptosis, which was demonstrated by increased TUNEL assay positivity and caspase 3 activation in the murine GSD-Ia liver. These analyses of hepatic involvement in GSD-Ia mice have implicated the induction of apoptosis in the pathobiology of GSD-Ia.
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Affiliation(s)
- Baodong Sun
- Division of Medical Genetics, Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA
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Yoon YS, Seo WY, Lee MW, Kim ST, Koo SH. Salt-inducible kinase regulates hepatic lipogenesis by controlling SREBP-1c phosphorylation. J Biol Chem 2009; 284:10446-52. [PMID: 19244231 DOI: 10.1074/jbc.m900096200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Liver plays a major role in regulating energy homeostasis in mammals. During feeding conditions, excessive glucose is converted into a preferred storage form of energy sources as triacylglycerol in liver via a collective metabolic pathway termed lipogenesis. Sterol regulatory element-binding protein 1c is a master regulator for this process by activating number of enzyme genes, such as Fasn or Acaca, that are involved in this pathway at the transcriptional level. Here we show that the salt-inducible kinase (SIK) family of proteins regulates the hepatic lipogenesis by modulating SREBP-1c activity. Overexpression of SIK1 inhibits hepatic expression of lipogenic genes, such as Fasn, whereas knockdown of SIK1 in liver greatly enhances their expression. Regulation of the Fasn gene by SIK kinases is mediated at the level of transcription via phosphorylation and inactivation of nuclear SREBP-1c. Among candidate sites for SIK-dependent regulation of SREBP-1c, the serine 329 residue is shown to be a critical regulatory site for SIK-mediated repression of SREBP-1c activity by in vitro kinase assay and reverse transcription-PCR analysis in primary hepatocytes. Finally, reduced hepatic triacylglycerol levels and lipogenic gene expression by adenoviral SIK1 transgenic expression are restored to normal levels by co-infection of mutant SREBP-1c, suggesting that SIK-dependent regulation of hepatic lipogenesis is indeed mediated through the phosphorylation of SREBP-1c in vivo. The process for the development of nonalcoholic fatty liver involves de novo lipogenesis via the activation of SREBP-1c. Modulation of SREBP-1c activity by SIK proteins would provide an attractive means for the regulation of such diseases.
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Affiliation(s)
- Young-Sil Yoon
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, 300 Chunchun-dong, Jangan-gu, Suwon, Gyeonggi-do 440-746, Korea
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Top-down systems biology integration of conditional prebiotic modulated transgenomic interactions in a humanized microbiome mouse model. Mol Syst Biol 2008; 4:205. [PMID: 18628745 PMCID: PMC2516362 DOI: 10.1038/msb.2008.40] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2008] [Accepted: 05/21/2008] [Indexed: 01/08/2023] Open
Abstract
Gut microbiome-host metabolic interactions affect human health and can be modified by probiotic and prebiotic supplementation. Here, we have assessed the effects of consumption of a combination of probiotics (Lactobacillus paracasei or L. rhamnosus) and two galactosyl-oligosaccharide prebiotics on the symbiotic microbiome-mammalian supersystem using integrative metabolic profiling and modeling of multiple compartments in germ-free mice inoculated with a model of human baby microbiota. We have shown specific impacts of two prebiotics on the microbial populations of HBM mice when co-administered with two probiotics. We observed an increase in the populations of Bifidobacterium longum and B. breve, and a reduction in Clostridium perfringens, which were more marked when combining prebiotics with L. rhamnosus. In turn, these microbial effects were associated with modulation of a range of host metabolic pathways observed via changes in lipid profiles, gluconeogenesis, and amino-acid and methylamine metabolism associated to fermentation of carbohydrates by different bacterial strains. These results provide evidence for the potential use of prebiotics for beneficially modifying the gut microbial balance as well as host energy and lipid homeostasis.
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Davies MN, O'Callaghan BL, Towle HC. Glucose activates ChREBP by increasing its rate of nuclear entry and relieving repression of its transcriptional activity. J Biol Chem 2008; 283:24029-38. [PMID: 18591247 DOI: 10.1074/jbc.m801539200] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Carbohydrate response element-binding protein (ChREBP) is a glucose-responsive transcription factor that activates genes involved in de novo lipogenesis in mammals. The current model for glucose activation of ChREBP proposes that increased glucose metabolism triggers a cytoplasmic to nuclear translocation of ChREBP that is critical for activation. However, we find that ChREBP actively shuttles between the cytoplasm and nucleus in both low and high glucose in the glucose-sensitive beta cell-derived line, 832/13. Glucose stimulates a 3-fold increase in the rate of ChREBP nuclear entry, but trapping ChREBP in the nucleus by mutagenesis or with a nuclear export inhibitor does not lead to constitutive activation. In fact, mutational studies targeting the nuclear export signal of ChREBP also identified a distinct function essential for glucose-dependent transcriptional activation. From this, we conclude that an additional event independent of nuclear translocation is required for activation. The N-terminal segment of ChREBP (amino acids 1-298) has previously been shown to repress activity under basal conditions. This segment has five highly conserved regions, Mondo conserved regions 1-5 (MCR1 to -5). Based on activating mutations in MCR2 and MCR5, we propose that these two regions act coordinately to repress ChREBP in low glucose. In addition, other mutations in MCR2 and mutations in MCR3 were found to prevent glucose activation. Hence, we conclude that both relief of repression and adoption of an activating form are required for ChREBP activation.
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Affiliation(s)
- Michael N Davies
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, 321 Church Street SE, Minneapolis, MN 55455, USA
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Abstract
PURPOSE OF REVIEW The liver is responsible for the conversion of excess dietary carbohydrates into fatty acids, through de-novo lipogenesis. A clear understanding of the control of lipogenesis is crucial since excess fatty acids leads to hepatic steatosis and associated metabolic diseases. The transcription factor sterol regulatory element binding protein 1c and the nuclear receptor liver X receptor are implicated in the insulin-mediated induction of lipogenic genes. Recently, the transcription factor carbohydrate responsive element binding protein has emerged as the hepatic glucose sensor required for the induction of lipogenic genes in response to glucose. RECENT FINDINGS We have recently demonstrated that the liver-specific inhibition of carbohydrate responsive element binding protein decreases the rate of lipogenesis and improves hepatic steatosis and insulin resistance in obese ob/ob mice. These results suggest that carbohydrate responsive element binding protein is a potential therapeutic target, and an accurate knowledge of the mechanisms involved in regulating its expression or activation is needed for the development of pharmacological approaches for the treatment of metabolic diseases. Recent studies report that carbohydrate responsive element binding protein is regulated at the transcriptional level by glucose and by liver X receptor but that posttranslational modifications are needed for carbohydrate responsive element binding protein to become active. SUMMARY Here we review some of the studies that provided a better understanding of the role and regulation of the newly identified transcription factor carbohydrate responsive element binding protein in lipid homeostasis.
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Affiliation(s)
- Pierre-Damien Denechaud
- Cochin Institute, Department of Endocrinology, Metabolism and Cancer, Paris Descartes University, CNRS (UMR 8104), Paris, France
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Kirchner S, Muduli A, Casirola D, Prum K, Douard V, Ferraris RP. Luminal fructose inhibits rat intestinal sodium-phosphate cotransporter gene expression and phosphate uptake. Am J Clin Nutr 2008; 87:1028-38. [PMID: 18400728 PMCID: PMC2430509 DOI: 10.1093/ajcn/87.4.1028] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND While searching by microarray for sugar-responsive genes, we inadvertently discovered that sodium-phosphate cotransporter 2B (NaPi-2b) mRNA concentrations were much lower in fructose-perfused than in glucose-perfused intestines of neonatal rats. Changes in NaPi-2b mRNA abundance by sugars were accompanied by similar changes in NaPi-2b protein abundance and in rates of inorganic phosphate (Pi) uptake. OBJECTIVE We tested the hypothesis that luminal fructose regulates NaPi-2b. DESIGN We perfused into the intestine fructose, glucose, and nonmetabolizable or poorly transported glucose analogs as well as phlorizin. RESULTS NaPi-2b mRNA concentrations and Pi uptake rates in fructose-perfused intestines were approximately 30% of those in glucose and its analogs. NaPi-2b inhibition by fructose is specific because the mRNA abundance and activity of the fructose transporter GLUT5 (glucose transporter 5) increased with fructose perfusion, whereas those of other transporters were independent of the perfusate. Plasma Pi after 4 h of perfusion was independent of the perfusate, probably because normal kidneys can maintain normophosphatemia. Inhibiting glucose-6-phosphatase, another fructose-responsive gene, with tungstate or vanadate nonspecifically inhibited NaPi-2b mRNA expression and Pi uptake in both glucose- or fructose-perfused intestines. The AMP kinase (AMPK)-activator AICAR (5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside) enhanced and the fatty acid synthase-AMPK inhibitor C75 (3-carboxy-4-octyl-2-methylenebutyrolactone trans-4-carboxy-5-octyl-3-methylenebutyrolactone) prevented fructose inhibition of NaPi-2b but had no effect on expression of other transporters. NaPi-2b expression decreased markedly with age and was inhibited by fructose in all age groups. CONCLUSIONS Energy levels in enterocytes may play a role in NaPi-2b inhibition by luminal fructose. Consumption of fructose that supplies approximately 10% of caloric intake by Americans clearly affects absorption of Pi and may promote Pi homeostasis in patients with impaired renal function.
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Affiliation(s)
- Séverine Kirchner
- Department of Pharmacology and Physiology, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark, NJ 07103-2714, USA
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Zhao WH, Zhao CY, Gao LF, Feng FF, Gao W, Chen ZL, Zhang F, Cao LG, Bi XY, Chen Y, Zhu QY, Zhang YX. The novel inhibitory effect of Pangdahai on fatty acid synthase. IUBMB Life 2008; 60:185-94. [DOI: 10.1002/iub.28] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
There is a renewed interest in the ultimate role of fatty acid synthase (FASN)--a key lipogenic enzyme catalysing the terminal steps in the de novo biogenesis of fatty acids--in cancer pathogenesis. Tumour-associated FASN, by conferring growth and survival advantages rather than functioning as an anabolic energy-storage pathway, appears to necessarily accompany the natural history of most human cancers. A recent identification of cross-talk between FASN and well-established cancer-controlling networks begins to delineate the oncogenic nature of FASN-driven lipogenesis. FASN, a nearly-universal druggable target in many human carcinomas and their precursor lesions, offers new therapeutic opportunities for metabolically treating and preventing cancer.
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Affiliation(s)
- Javier A Menendez
- Translational Research Unit, Catalan Institute of Oncology (ICO), Health Services Division of Catalonia, Girona Biomedical Research Institute (IdIBGi), Medical Oncology, Josep Trueta University Hospital of Girona, 17,007 Girona, Catalonia, Spain
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Maloney CA, Lilley C, Czopek A, Hay SM, Rees WD. Interactions between protein and vegetable oils in the maternal diet determine the programming of the insulin axis in the rat. Br J Nutr 2007; 97:912-20. [PMID: 17408526 DOI: 10.1017/s0007114507659042] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The available evidence suggests that metabolic control mechanisms are programmed early in life. Previous studies of pregnant rats fed low-protein diets have suggested that the vegetable oils used in the experimental diets influence the outcome. The present study investigated the offspring of female rats fed semi-synthetic diets containing either 180 or 90 g casein/kg with 70 g/kg (w/w) of either corn oil or soya oil during gestation. During lactation, the dams received stock diet, and the offspring were subsequently weaned onto the stock diet. The offspring of dams fed the low-protein diets were smaller at birth. At 25 weeks of age, the offspring were subjected to an oral glucose tolerance test. In the offspring of dams fed the diet containing soya oil, the area under the insulin curve was affected by the protein content of the maternal diet. There was no effect of protein on the area under the insulin curve in the offspring of dams fed the diet prepared with corn oil. There were no differences in plasma glucose concentrations. The levels of mRNA for acetyl-CoA carboxylase-1 in the livers of female offspring were affected by the protein and oil content of the maternal diet. The level of carnitine palmitoyl transferase mRNA was affected by the protein content of the maternal diet. The present study suggests that PUFA in the maternal diet can interact with protein metabolism to influence the development of the offspring. This may involve the higher content of α-linolenic acid in soya oil compared with corn oil.
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Teran-Garcia M, Adamson A, Yu G, Rufo C, Suchankova G, Dreesen T, Tekle M, Clarke S, Gettys T. Polyunsaturated fatty acid suppression of fatty acid synthase (FASN): evidence for dietary modulation of NF-Y binding to the Fasn promoter by SREBP-1c. Biochem J 2007; 402:591-600. [PMID: 17313375 PMCID: PMC1863568 DOI: 10.1042/bj20061722] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Dietary PUFAs (polyunsaturated fatty acids) co-ordinately suppress transcription of a group of hepatic genes encoding glycolytic and lipogenic enzymes. Suppression of Fasn (fatty acid synthase) transcription involves two PUFA-responsive regions, but the majority of PUFA sensitivity maps to a region within the proximal promoter containing binding sites for NF-Y (nuclear factor-Y), Sp1 (stimulatory protein 1), SREBP (sterol-regulatory-elementbinding protein), and USF (upstream stimulatory factor). Promoter activation assays indicate that altered NF-Y is the key component in regulation of Fasn promoter activity by PUFA. Using electrophoretic mobility-shift assay and chromatin immunoprecipitation analysis, we demonstrate for the first time that PUFAs decrease in vivo binding of NF-Y and SREBP-1c to the proximal promoter of the hepatic Fasn gene and the promoters of three additional genes, spot 14, stearoyl-CoA desaturase and farnesyl diphosphate synthase that are also down-regulated by PUFA. The comparable 50% decrease in NF-Y and SREBP-1c binding to the promoters of the respective PUFA-sensitive genes occurred despite no change in nuclear NF-Y content and a 4-fold decrease in SREBP-1c. Together, these findings support a mechanism whereby PUFA reciprocally regulates the binding of NF-Y and SREBP-1c to a subset of genes which share similar contiguous arrangements of sterol regulatory elements and NF-Y response elements within their promoters. PUFA-dependent regulation of SREBP-1c and NF-Y binding to this unique configuration of response elements may represent a nutrient-sensitive motif through which PUFA selectively and co-ordinately targets subsets of hepatic genes involved in lipid metabolism.
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Affiliation(s)
- Margarita Teran-Garcia
- *Department of Adipocyte Signalling, Pennington Biomedical Research Center, Baton Rouge, LA 70808, U.S.A
| | - Aaron W. Adamson
- *Department of Adipocyte Signalling, Pennington Biomedical Research Center, Baton Rouge, LA 70808, U.S.A
| | - Gang Yu
- *Department of Adipocyte Signalling, Pennington Biomedical Research Center, Baton Rouge, LA 70808, U.S.A
| | - Caterina Rufo
- †Catedra de Inmunologia, Facultad de Quimica, Universidad de la Republica, Instituto de Higiene, Montevideo, Uruguay
| | | | | | - Michael Tekle
- *Department of Adipocyte Signalling, Pennington Biomedical Research Center, Baton Rouge, LA 70808, U.S.A
| | | | - Thomas W. Gettys
- *Department of Adipocyte Signalling, Pennington Biomedical Research Center, Baton Rouge, LA 70808, U.S.A
- To whom correspondence should be addressed (email )
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FUKUDA H, HIRAKAWA T, IRITANI N. Nutritional and Hormonal Regulation of Uncoupling Protein Gene Expression in Rat Adipocytes. J Nutr Sci Vitaminol (Tokyo) 2007; 53:426-31. [DOI: 10.3177/jnsv.53.426] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Hitomi FUKUDA
- Faculty of Human and Cultural Studies, Tezukayama Gakuin University
| | - Tomoe HIRAKAWA
- Faculty of Human and Cultural Studies, Tezukayama Gakuin University
| | - Nobuko IRITANI
- Faculty of Human and Cultural Studies, Tezukayama Gakuin University
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Nakashima Y. Ratio of High-Fat Diet Intake of Pups Nursed by Dams Fed Combination Diet Was Lower Than That of Pups Nursed by Dams Fed High-Fat or Low-Fat Diet. J Nutr Sci Vitaminol (Tokyo) 2007; 53:117-23. [PMID: 17615998 DOI: 10.3177/jnsv.53.117] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
To investigate the influence of fat-feeding dams on the food choice of their pups after weaning, each of three groups of dams was fed a low-fat diet (LHD), a high-fat diet (HFD) or a two-choice diet of LFD and HFD during pregnancy and lactation. Immediately after weaning, all pups were placed on a two-choice diet program for 5 wk. The fat energy ratio (F ratio) for dams fed the two-choice diet was 31%. Although no significant differences in body weight or calorie intake were observed between these three groups of dams, liver and perirenal fat tissue weights and plasma and liver trigluceride and total-cholesterol concentrations were lower in dams fed the two-choice diet than in dams fed LHD or HFD. Both groups of pups nursed by dams fed LFD or HFD continued to eat a large amount of HFD after weaning (F ratio was over 40%). Although within first week after weaning, no significant difference in the ratio of HFD intake was observed among the three groups of pups, the ratio for pups nursed by dams fed the two-choice diet decreased after the second week. The F ratio for pups nursed by dams fed the two-choice diet was 32%. These data lead us to conclude that if dams ate more than one diet in an adequate PFC ratio, their pups would have the ability to eat adequately after weaning.
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Affiliation(s)
- Yoko Nakashima
- Department of Human Life and Culture, Seitoku University, 550 Iwase, Matsudo 271-8555, Japan.
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Yadav H, Jain S, Sinha PR. Effect of Skim Milk and Dahi (Yogurt) on Blood Glucose, Insulin, and Lipid Profile in Rats Fed with High Fructose Diet. J Med Food 2006; 9:328-35. [PMID: 17004894 DOI: 10.1089/jmf.2006.9.328] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In the present study, the effect of skim milk and the fermented milk product named dahi (yogurt) on plasma glucose, insulin, and lipid levels as well as on liver glycogen and lipid contents in rats fed with high fructose diet has been investigated. Rats were fed with high fructose diet (21%) supplemented with skim milk, dahi (10 g/day each), or no milk product (control group) for 6 weeks. After 6 weeks of high fructose diet administration, the plasma glucose became significantly higher in control animals (246 mg/dL), whereas it was lower in skim milk (178 mg/dL)- and dahi (143 mg/dL)-fed rats. The glucose tolerance became impaired at the third week of feeding of high fructose diet in control animals, whereas in skim milk- and dahi-fed animals achievement of glucose intolerance was delayed until the fourth and fifth week, respectively. Blood glycosylated hemoglobin and plasma insulin were significantly lower in skim milk (10% and 34%, respectively)- and dahi (17%, and 48%, respectively)-fed animals than those of the control group. Plasma total cholesterol, triglycerides, low-density lipoprotein-cholesterol, and very-low-density lipoprotein-cholesterol and blood free fatty acids were significantly lower in skim milk (13%, 14%, 14%, 19%, and 14%, respectively)- and dahi (22%, 33%, 30%, 33%, and 29%, respectively)-fed animals as compared with control animals. Moreover, the total cholesterol, triglyceride, and glycogen contents in liver tissues were also lower in skim milk (55%, 50%, and 36%, respectively)- and dahi (64%, 27%, and 4%, respectively)-fed animals as compared with control animals. In contrast, high-density lipoprotein-cholesterol in plasma was higher in skim milk (14%)- and dahi (29%)-fed animals as compared with control animals. These results indicate that skim milk and its fermented milk product, dahi, delay the progression of fructose-induced diabetes and dyslipidemia in rats and that these may be useful as antidiabetic food supplements that can be included in daily meals of the diabetic as well as normal population.
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Affiliation(s)
- Hariom Yadav
- Animal Biochemistry Division, National Dairy Research Institute, Karnal, Haryana, India.
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Lupu R, Menendez JA. Targeting fatty acid synthase in breast and endometrial cancer: An alternative to selective estrogen receptor modulators? Endocrinology 2006; 147:4056-66. [PMID: 16809439 DOI: 10.1210/en.2006-0486] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
There is an urgent need to identify and develop a new generation of therapeutic agents and systemic therapies targeting the estradiol (E2)/estrogen receptor (ER) signaling in breast cancer. In this regard, new information on the mechanisms of E2/ER function and/or cross talk with other prosurvival cascades should provide the basis for the development of other ideal anti-E2 therapies with the intent to enhance clinical efficacy, reduce side effects or both. Our very recent assessment of the mechanisms by which cancer-associated increased lipogenesis and its inhibition alters the E2/ER signaling discovered that fatty acid synthase (FASN), the enzyme catalyzing the terminal steps in the de novo biosynthesis of long-chain fatty acids, differentially modulates the state of sensitivity of breast and endometrial cancer cells to E2-stimulated ER transcriptional activation and E2-dependent cell growth and survival: 1) pharmacological inhibition of FASN activity induced a dramatic augmentation of E2-stimulated ER-driven gene transcription, whereas interference (RNAi)-mediated silencing of FAS gene expression drastically lowered E2 requirements for optimal activation of ER transcriptional activation in breast cancer cells; conversely, pharmacological and RNAi-induced inhibition of FASN worked as an antagonist of E2- and tamoxifen-dependent ER transcriptional activity in endometrial adenocarcinoma cells; 2) pharmacological and RNAi-induced inhibition of FASN synergistically enhanced E2-mediated down-regulation of ER protein and mRNA expression in breast cancer cells, whereas specific FASN blockade resulted in a marked down-regulation of E2-stimulated ER expression in endometrial cancer cells; and 3) FASN inhibition decreased cell proliferation and cell viability by promoting apoptosis in hormone-dependent breast and endometrial cancer cells. In this review we propose that, through a complex mechanism involving the regulation of MAPK/ER cross talk as well as critical E2-related proteins including the Her-2/neu (erbB-2) oncogene and the cyclin-dependent kinase inhibitors p21(WAF1/CIP1) and p27(Kip1), a previously unrevealed connection exists between FASN and the genomic and nongenomic ER activities in breast and endometrial cancer cells. From a clinical perspective, we suggest that if chemically stable FASN inhibitors or cell-selective systems able to deliver RNAi targeting FASN gene demonstrate systemic anticancer effects of FASN inhibition in vivo, additional preclinical studies to characterize their anti-breast cancer actions should be of great interest as the specific blockade of FASN activity may also provide a protective means against endometrial carcinoma associated with tamoxifen-based breast cancer therapy.
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Affiliation(s)
- Ruth Lupu
- Department of Medicine, Evanston Northwestern Healthcare Research Institute, 1001 University Place, Evanston, Illinois 60201, USA.
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Menendez JA, Lupu R. Oncogenic properties of the endogenous fatty acid metabolism: molecular pathology of fatty acid synthase in cancer cells. Curr Opin Clin Nutr Metab Care 2006; 9:346-57. [PMID: 16778562 DOI: 10.1097/01.mco.0000232893.21050.15] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW This review documents our rapidly changing perspectives on the function of fatty acid synthase-catalyzed endogenous fatty acid biogenesis in cancer biology. RECENT FINDINGS Up-regulation of fatty acid synthase gene expression and fatty acid synthase biosynthetic activity are molecular events accompanying the pathogenesis and natural history of cancer disease. First, the increased fatty acid synthase gene expression in precursor, preinvasive and invasive cancer lesions appears to represent an indirect, early epiphenomenon, occurring in response to a microenvironment containing regions of poor oxygenation and high acidity due to, for example, lack of an adequate angiogenesis and/or nutritional supply. Second, aberrant transduction cascades driven by cancer-associated oncogenic changes subvert the downregulatory effects of circulating fatty acids. Third, fatty acid synthase-dependent endogenous fatty acid metabolism actively contributes to cancer evolution by specifically regulating the expression, activity and/or cellular localization of proteins closely related to malignant transformation and/or cancer progression. SUMMARY Fatty acid synthase-catalyzed endogenous fatty acid metabolism appears to be an obligatory acquisition selecting a biologically aggressive sub-group of cancer cells capable of growth and survival upon stresses such as hypoxia, low pH and/or nutritional deprivation. Considering that an ever-growing body of evidence demonstrates that fatty acid synthase-driven signalling actively regulates key cancer-controlling networks, we may hereafter redefine fatty acid synthase as a metabolic oncogene in human cancer cells.
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Affiliation(s)
- Javier A Menendez
- Foundation of the Recerca Bio-Medical Institute of Girona Dr Josep Trueta, University Hospital of Girona, Dr Josep Trueta, Girona, Catalonia, Spain.
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Al-Hasani H, Joost HG. Nutrition-/diet-induced changes in gene expression in white adipose tissue. Best Pract Res Clin Endocrinol Metab 2005; 19:589-603. [PMID: 16311219 DOI: 10.1016/j.beem.2005.07.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Nutrients regulate metabolic fluxes and homeostasis through transcriptional and translational control of enzyme concentrations and allosteric modulation of enzyme activity. Dietary omega-3 polyunsaturated fatty acids (PUFAs) have been shown to exert a variety of beneficial health effects such as reducing adiposity and increasing insulin sensitivity in rodents. It is now clear that PUFAs regulate fundamental adipose cell and liver functions through modulation of activity and abundance of key transcription factors that act as nutrient sensors, including peroxisome proliferator-activated receptors (PPARalpha/delta/gamma), sterol regulatory element binding proteins (SREBP-1/2), and liver X receptors (LXRalpha/beta). However, in the state of obesity, where adipose tissue shows elevated storage of triglycerides, many lipogenic genes that are essential for adipose cell function including PPARgamma, SREBP-1c, CCAAT-enhancer binding protein alpha and stearoyl-CoA desaturase-1 are downregulated, apparently due to desensitization of the very same crucial nutrient sensors. This chapter will summarize recent studies of PUFA- and obesity-induced changes in gene expression in white adipose tissue.
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Affiliation(s)
- Hadi Al-Hasani
- German Institute for Human Nutrition, Potsdam-Rehbrücke, Arthur-Scheunert-Allee 114-116, D-14558 Nuthetal, Germany.
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Morifuji M, Sakai K, Sanbongi C, Sugiura K. Dietary whey protein downregulates fatty acid synthesis in the liver, but upregulates it in skeletal muscle of exercise-trained rats. Nutrition 2005; 21:1052-8. [PMID: 16157243 DOI: 10.1016/j.nut.2005.01.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2004] [Accepted: 01/28/2005] [Indexed: 11/20/2022]
Abstract
OBJECTIVE This study compared the effects of casein and whey protein as the source of dietary protein on the activity of lipogenic enzymes and mRNA levels in the liver and skeletal muscle of exercise-trained rats. METHODS Twenty-eight male Sprague-Dawley rats were randomly assigned to one of four groups (n = 7/group). Rats were assigned to sedentary or exercise-trained groups and were fed the casein or whey protein diet. Rats in the exercise groups were trained for 2 wk using a swimming exercise for 120 min/d and 6 d/wk. RESULTS A significant decrease in the activity of the hepatic lipogenic enzymes, glucose-6-phosphate dehydrogenase, malic enzyme, adenosine triphosphate citrate lyase, acetyl-coenzyme A carboxylase, and fatty acid synthase (FASN) was observed in rats fed whey protein compared with animals fed casein. Compared with the casein diet, the whey protein diet also lowered mRNA expression of these enzymes, except for FASN. In contrast to the findings in liver, whey protein, as compared with casein, increased skeletal muscle FASN activity and mRNA. Further, exercise training resulted in increased skeletal muscle glucose-6-phosphate dehydrogenase and FASN activity and adenosine triphosphate citrate lyase, acetyl-coenzyme A carboxylase-1, and FASN mRNA expression. CONCLUSIONS Exercise training or whey protein may play an important role in suppressing hepatic fatty acid synthesis, thereby decreasing accumulation of body fat and stimulating the skeletal muscle to increase energy substrate as fat during prolonged exercise.
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Affiliation(s)
- Masashi Morifuji
- Health and Bioscience Laboratories, Meiji Seika Kaisha Ltd., Tokyo, Japan.
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Dentin R, Benhamed F, Pégorier JP, Foufelle F, Viollet B, Vaulont S, Girard J, Postic C. Polyunsaturated fatty acids suppress glycolytic and lipogenic genes through the inhibition of ChREBP nuclear protein translocation. J Clin Invest 2005; 115:2843-54. [PMID: 16184193 PMCID: PMC1224299 DOI: 10.1172/jci25256] [Citation(s) in RCA: 220] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2005] [Accepted: 07/19/2005] [Indexed: 12/19/2022] Open
Abstract
Dietary polyunsaturated fatty acids (PUFAs) are potent inhibitors of hepatic glycolysis and lipogenesis. Recently, carbohydrate-responsive element-binding protein (ChREBP) was implicated in the regulation by glucose of glycolytic and lipogenic genes, including those encoding L-pyruvate kinase (L-PK) and fatty acid synthase (FAS). The aim of our study was to assess the role of ChREBP in the control of L-PK and FAS gene expression by PUFAs. We demonstrated in mice, both in vivo and in vitro, that PUFAs [linoleate (C18:2), eicosapentanoic acid (C20:5), and docosahexaenoic acid (C22:6)] suppressed ChREBP activity by increasing ChREBP mRNA decay and by altering ChREBP translocation from the cytosol to the nucleus, independently of an activation of the AMP-activated protein kinase, previously shown to regulate ChREBP activity. In contrast, saturated [stearate (C18)] and monounsaturated fatty acids [oleate (C18:1)] had no effect. Since glucose metabolism via the pentose phosphate pathway is determinant for ChREBP nuclear translocation, the decrease in xylulose 5-phosphate concentrations caused by a PUFA diet favors a PUFA-mediated inhibition of ChREBP translocation. In addition, overexpression of a constitutive nuclear ChREBP isoform in cultured hepatocytes significantly reduced the PUFA inhibition of both L-PK and FAS gene expression. Our results demonstrate that the suppressive effect of PUFAs on these genes is primarily caused by an alteration of ChREBP nuclear translocation. In conclusion, we describe a novel mechanism to explain the inhibitory effect of PUFAs on the genes encoding L-PK and FAS and demonstrate that ChREBP is a pivotal transcription factor responsible for coordinating the PUFA suppression of glycolytic and lipogenic genes.
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Affiliation(s)
- Renaud Dentin
- Département d'Endocrinologie, Institut Cochin, INSERM U567 CNRS UMR8104, Université René Descartes, Paris, France
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Rho HK, Park J, Suh JH, Kim JB. Transcriptional regulation of mouse 6-phosphogluconate dehydrogenase by ADD1/SREBP1c. Biochem Biophys Res Commun 2005; 332:288-96. [PMID: 15896329 DOI: 10.1016/j.bbrc.2005.04.120] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2005] [Accepted: 04/23/2005] [Indexed: 11/21/2022]
Abstract
6-Phosphogluconate dehydrogenase (6PGDH) constitutes the pentose phosphate pathway and produces NADPH. 6PGDH is also considered as a lipogenic gene since NADPH is a pivotal cofactor for lipogenesis. Thus, it is important to elucidate how 6PGDH is regulated by various signals related to energy homeostasis. Here, we provide several evidences that ADD1/SREBP1c regulates the expression of mouse 6PGDH gene. DNase I footprinting assay and point mutation studies revealed that the E-box (CANNTG) motif in the promoter of mouse 6PGDH is an important cis-regulatory element for ADD1/SREBP1c. 6PGDH mRNA is highly expressed in white adipose tissue and tightly modulated by nutritional status. Furthermore, we found that ADD1/SREBP1c mediates insulin-dependent 6PGDH expression and that PI3-kinase is an important linker for its regulation. Taken together, these data suggest that ADD1/SREBP1c is a key transcription factor for 6PGDH gene expression and would coordinate glucose metabolism and lipogenesis for energy homeostasis.
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Affiliation(s)
- Ho Kyung Rho
- Department of Biological Sciences, Seoul National University, Seoul 151-742, Republic of Korea
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Huang W, Wood C, L'Abbé MR, Gilani GS, Cockell KA, Xiao CW. Soy protein isolate increases hepatic thyroid hormone receptor content and inhibits its binding to target genes in rats. J Nutr 2005; 135:1631-5. [PMID: 15987841 DOI: 10.1093/jn/135.7.1631] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Our previous studies showed that intake of 20% alcohol-washed soy protein isolate (SPI) significantly increased hepatic thyroid hormone receptor (TR) beta1 protein content in rats. However, whether SPI influences the binding ability of TR to its target genes is unknown. The purpose of this study was to examine the effect of increasing amounts of dietary SPI on hepatic TRbeta1 content and the binding of TR to thyroid hormone response element (TRE) in rats. Sprague-Dawley rats (28 d old) were fed diets containing casein (20%) with or without isoflavone supplementation (50 mg/kg diet) or alcohol-washed SPI (5, 10, or 20%) for 90 d. The hepatic TRbeta1 protein content was measured by Western blot, and the binding ability of TR to DNA was examined by electrophoretic mobility shift assay. Consumption of the 20% SPI diet increased pancreatic relative weight and decreased spleen relative weight. Intake of SPI markedly elevated TRbeta1 content in both male and female rats compared with a casein-based control diet. The increase in TRbeta1 in females was much higher than that in males. Interestingly, the binding abilities of TR to DNA were significantly inhibited by increasing amounts of dietary SPI in female rats. In conclusion, this study shows for the first time that dietary SPI increases hepatic TRbeta1 protein content and inhibits the binding of TR to target genes. Modulation of hepatic TRbeta1, a key regulator of gene expression involved in lipid metabolism, by SPI may be a novel mechanism by which soy components lower blood lipid level and exert their hypocholesterolemic actions.
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Affiliation(s)
- Wenxin Huang
- Nutrition Research Division, Food Directorate, Health Products and Food Branch, Health Canada, Banting Research Centre, Ottawa, ON, Canada K1A 0L2
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Dentin R, Girard J, Postic C. Carbohydrate responsive element binding protein (ChREBP) and sterol regulatory element binding protein-1c (SREBP-1c): two key regulators of glucose metabolism and lipid synthesis in liver. Biochimie 2005; 87:81-6. [PMID: 15733741 DOI: 10.1016/j.biochi.2004.11.008] [Citation(s) in RCA: 251] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2004] [Accepted: 11/02/2004] [Indexed: 12/14/2022]
Abstract
In mammals, the regulation of hepatic metabolism plays a key role in whole body energy balance, since the liver is the major site of carbohydrate metabolism (glycolysis and glycogen synthesis) and triglyceride synthesis (lipogenesis). Lipogenesis is regulated through the acute control of key enzyme activities by means of allosteric and covalent modifications. Moreover, the synthesis of most glycolytic and lipogenic enzymes is regulated in response to dietary status, in which glucose, in particular, is a crucial energy nutrient. This latter response occurs in large part through transcriptional regulation of genes encoding glycolytic and lipogenic enzymes. In the past few years, recent advances have been made in understanding the transcriptional regulation of hepatic glycolytic and lipogenic genes by insulin and glucose. Although insulin is a major regulator of hepatic lipogenesis, there is increasing evidence that glucose also contributes to the coordinated regulation of carbohydrate and lipid metabolism in liver. Here, we review the respective roles of the transcription factor sterol regulatory element binding protein-1c (SREBP-1c) in mediating the effect of insulin on hepatic gene expression, and the role of carbohydrate responsive element binding protein (ChREBP) in regulating gene transcription by glucose.
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Affiliation(s)
- Renaud Dentin
- Département d'Endocrinologie, Institut Cochin, Inserm U567, CNRS UMR8104, Université Paris V René Descartes, 24, rue du Faubourg Saint Jacques, 75014 Paris, France
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Menendez JA, Colomer R, Lupu R. Why does tumor-associated fatty acid synthase (oncogenic antigen-519) ignore dietary fatty acids? Med Hypotheses 2005; 64:342-9. [PMID: 15607569 DOI: 10.1016/j.mehy.2004.07.022] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2004] [Accepted: 07/09/2004] [Indexed: 12/13/2022]
Abstract
The hyperactivation of fatty acid synthase (FAS)-catalyzed de novo biosynthesis of fatty acids is a molecular marker linked to tumor virulence in population studies of human malignancies. This activation appears to be linked to neoplastic transformation, since high levels of FAS have also been identified in pre-malignant lesions. This dependence of cancer upon accelerated lipogenesis differs from normal human tissues, in which FAS is suppressed by the presence of small amounts of fatty acids in the diet. The molecular mechanisms by which cancer cells constitutively exhibit FAS overexpression and hyperactivity have begun to emerge. The active involvement of the mitogen-activated protein kinase (MAPK) extracellular signal-regulated kinase (MAPK ERK1/2) and phosphatidylinositol-3'-kinase (PI-3'K)/protein kinase B (AKT) transduction cascades in the overexpression of FAS has been recently demonstrated in several cancer cell models. Strikingly, insulin-regulated stimulation of FAS expression in adipose cells is also mediated by the PI-3'K pathway with AKT being involved as a downstream effector. Moreover, FAS overexpression in tumor cells has been demonstrated to occur through a modification of the transcription factor sterol regulatory element-binding protein-1c (SREBP-1c), the major regulatory factor of FAS in liver and adipose tissues, which, in turn, is known to be regulated by MAPK ERK1/2 and PI-3'K/AKT pathways. Therefore, the signal transduction pathways regulating FAS expression in normal and cancer cells seem to share several downstream elements. However, the upstream mechanisms controlling FAS expression in cancer cells must be different from those in normal tissues, since tumor-associated FAS expression seems to be insensitive to nutritional signals. In pre-neoplastic lesions, we hypothesize that the early activation of FAS in pre-malignant cells represents a survival strategy which occurs to compensate for an insufficiency of both oxygen and dietary fatty acids due to, e.g., lack of angiogenesis. Thus, FAS activation reflects an epigenetic dysregulation of the lipogenic pathway in response to the microenvironment of tumors containing regions of poor oxygenation. Upon this unusual metabolic situation, FAS up-regulation also represent a metabolic strategy to maintain high proliferation rates of surviving cells in the absence of exogenous dietary fatty acids. Concomitantly, a variety of oncogenic changes (H-ras, erb B-2, etc.) may result in the constitutive activation of MAPK and PI-3'K/AKT signaling cascades, which, in turn, can activate SREBP-1c and, subsequently, tumor-associated FAS-catalyzed endogenous lipogenesis. Thereafter, high levels of FAS are maintained in coordination with increased demand for fatty acid metabolism and/or membrane synthesis in response to cancer-related overexpression of growth factors (e.g., EGF, heregulin) and/or growth factor receptors (e.g., EGFR, Her-2/neu). The aberrant MAPK and PI-3'K/AKT cascades driven by these oncogenic changes subvert the downregulatory effects of physiological concentrations of dietary fatty acids, resulting in a cancer-associated FAS insensitivity to nutritional signals. This model does not exclude that fundamental differences in the ability of FAS gene to respond to normal fatty acid's downregulatory actions may also synergistically interact with oncogenic signals to constitutively maintain an elevated FAS-dependent de novo endogenous fatty acid biogenesis in cancer cells in spite of high levels of circulating dietary fatty acids.
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Affiliation(s)
- Javier A Menendez
- Department of Medicine, Evanston Northwestern Healthcare Research Institute, 1001 University Place, Evanston, IL 60201, USA.
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Basciano H, Federico L, Adeli K. Fructose, insulin resistance, and metabolic dyslipidemia. Nutr Metab (Lond) 2005; 2:5. [PMID: 15723702 PMCID: PMC552336 DOI: 10.1186/1743-7075-2-5] [Citation(s) in RCA: 530] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2005] [Accepted: 02/21/2005] [Indexed: 12/31/2022] Open
Abstract
Obesity and type 2 diabetes are occurring at epidemic rates in the United States and many parts of the world. The "obesity epidemic" appears to have emerged largely from changes in our diet and reduced physical activity. An important but not well-appreciated dietary change has been the substantial increase in the amount of dietary fructose consumption from high intake of sucrose and high fructose corn syrup, a common sweetener used in the food industry. A high flux of fructose to the liver, the main organ capable of metabolizing this simple carbohydrate, perturbs glucose metabolism and glucose uptake pathways, and leads to a significantly enhanced rate of de novo lipogenesis and triglyceride (TG) synthesis, driven by the high flux of glycerol and acyl portions of TG molecules from fructose catabolism. These metabolic disturbances appear to underlie the induction of insulin resistance commonly observed with high fructose feeding in both humans and animal models. Fructose-induced insulin resistant states are commonly characterized by a profound metabolic dyslipidemia, which appears to result from hepatic and intestinal overproduction of atherogenic lipoprotein particles. Thus, emerging evidence from recent epidemiological and biochemical studies clearly suggests that the high dietary intake of fructose has rapidly become an important causative factor in the development of the metabolic syndrome. There is an urgent need for increased public awareness of the risks associated with high fructose consumption and greater efforts should be made to curb the supplementation of packaged foods with high fructose additives. The present review will discuss the trends in fructose consumption, the metabolic consequences of increased fructose intake, and the molecular mechanisms leading to fructose-induced lipogenesis, insulin resistance and metabolic dyslipidemia.
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Affiliation(s)
- Heather Basciano
- Clinical Biochemistry Division, Department of Laboratory Medicine and Pathobiology, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Lisa Federico
- Clinical Biochemistry Division, Department of Laboratory Medicine and Pathobiology, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Khosrow Adeli
- Clinical Biochemistry Division, Department of Laboratory Medicine and Pathobiology, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
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Kim HK, Choi S, Choi H. Suppression of hepatic fatty acid synthase by feeding alpha-linolenic acid rich perilla oil lowers plasma triacylglycerol level in rats. J Nutr Biochem 2004; 15:485-92. [PMID: 15302084 DOI: 10.1016/j.jnutbio.2004.02.010] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2003] [Revised: 02/07/2004] [Accepted: 02/15/2004] [Indexed: 12/22/2022]
Abstract
This study was performed to determine the effects of dietary perilla oil, a n-3 alpha-linolenic acid (ALA) source, on hepatic lipogenesis as a possible mechanism of lowering triacylglycerol (TG) levels. Male Sprague-Dawley rats were trained for a 3-hour feeding protocol and fed one of five semipurified diets as follows: 1% (w/w) corn oil control diet, or one of four diets supplemented with 10% each of beef tallow, corn oil, perilla oil, and fish oil. Two separate experiments were performed to compare the effects of feeding periods, 4 weeks and 4 days. Hepatic and plasma TG levels were decreased in rats fed perilla oil and fish oil diets, compared with corn oil and beef tallow diets. The activities of hepatic lipogenic enzymes such as fatty acid synthase (FAS), glucose-6-phosphate dehydrogenase, and malic enzyme were suppressed in the fish oil, perilla oil, and corn oil-fed groups, and the effect was the most significant in the fish oil-fed group. Also, the activities of glycolytic enzymes, glucokinase, and L-pyruvate kinase showed the similar trend as that of lipogenic enzymes. The activity of FAS, the key regulatory enzyme in lipogenesis, was positively correlated with hepatic and plasma TG levels and reduced significantly in the perilla oil-fed group compared with corn oil-fed group. In addition, the FAS activity was negatively correlated with the hepatic microsomal content of EPA and DHA. In conclusion, suppression of FAS plays a significant role in the hypolipidemic effects observed in rats fed ALA rich perilla oil and these effects were associated with the increase of hepatic microsomal EPA and DHA contents.
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Affiliation(s)
- Hye-Kyeong Kim
- Department of Food and Nutrition, Seoul National University, Korea
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Abstract
Globalization and global market have contributed to increased consumption of high-fat, energy-dense diets, particularly rich in saturated fatty acids( SFAs). Polyunsaturated fatty acids (PUFAs) regulate fuel partitioning within the cells by inducing their own oxidation through the reduction of lipogenic gene expression and the enhancement of the expression of those genes controlling lipid oxidation and thermogenesis. Moreover, PUFAs prevent insulin resistance by increasing membrane fluidity and GLUT4 transport. In contrast, SFAs are stored in non-adipocyte cells as triglycerides (TG) leading to cellular damage as a sequence of their lipotoxicity. Triglyceride accumulation in skeletal muscle cells (IMTG) derives from increased FA uptake coupled with deficient FA oxidation. High levels of circulating FAs enhance the expression of FA translocase the FA transport proteins within the myocites. The biochemical mechanisms responsible for lower fatty acid oxidation involve reduced carnitine palmitoyl transferase (CPT) activity, as a likely consequence of increased intracellular concentrations of malonyl-CoA; reduced glycogen synthase activity; and impairment of insulin signalling and glucose transport. The depletion of IMTG depots is strictly associated with an improvement of insulin sensitivity, via a reduced acetyl-CoA carboxylase (ACC) mRNA expression and an increased GLUT4 expression and pyruvate dehydrogenase (PDH) activity. In pancreatic islets, TG accumulation causes impairment of insulin secretion. In rat models, beta-cell dysfunction is related to increased triacylglycerol content in islets, increased production of nitric oxide, ceramide synthesis and beta-cell apoptosis. The decreased insulin gene promoter activity and binding of the pancreas-duodenum homeobox-1 (PDX-1) transcription factor to the insulin gene seem to mediate TG effect in islets. In humans, acute and prolonged effects of FAs on glucose-stimulated insulin secretion have been widely investigated as well as the effect of high-fat diets on insulin sensitivity and secretion and on the development of type 2 diabetes.
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Affiliation(s)
- Melania Manco
- Institute of Internal Medicine, Catholic University, 00168 Rome, Italy.
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Suzuki T, Hara H. Ingestion of guar gum hydrolysate, a soluble and fermentable nondigestible saccharide, improves glucose intolerance and prevents hypertriglyceridemia in rats fed fructose. J Nutr 2004; 134:1942-7. [PMID: 15284380 DOI: 10.1093/jn/134.8.1942] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Fructose feeding provides a dietary model of insulin resistance accompanied by hypertriglyceridemia. We examined the effects of guar gum hydrolysate (GGH), a soluble and fermentable nondigestible saccharide with low viscosity, on glucose intolerance and hypertriglyceridemia in rats fed high-fructose diets. Rats were fed either a dextrin-based or a fructose-based diet with or without GGH (75 g/kg) for 30 d. Oral glucose tolerance tests (OGTTs) were performed 0, 14, and 28 d after feeding. High-fructose feeding negatively affected glucose tolerance on d 14 and 28. The addition of GGH to the diets improved glucose intolerance on d 28. Fructose feeding induced hyperinsulinemia after an oral glucose load; this was also improved by GGH on d 28. The glycogen concentration in the gastrocnemius muscles of rats was lowered by dietary fructose, and GGH supplementation abolished this decrease. Triglycerides in the plasma and livers of rats fed fructose diets were elevated, and the increases were ameliorated by supplemental GGH. Regardless of the type of carbohydrate, GGH enlarged the cecum and increased the cecal SCFA pools. In conclusion, supplemental feeding of GGH to rats improved the glucose intolerance and hypertriglyceridemia induced by a high-fructose diet. Possible mediators of these beneficial effects of GGH are the SCFAs produced by microbial fermentation of GGH in the large intestine.
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Affiliation(s)
- Takuya Suzuki
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
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Matsumoto M, Ogawa W, Akimoto K, Inoue H, Miyake K, Furukawa K, Hayashi Y, Iguchi H, Matsuki Y, Hiramatsu R, Shimano H, Yamada N, Ohno S, Kasuga M, Noda T. PKCλ in liver mediates insulin-induced SREBP-1c expression and determines both hepatic lipid content and overall insulin sensitivity. J Clin Invest 2003. [DOI: 10.1172/jci200318816] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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Matsumoto M, Ogawa W, Akimoto K, Inoue H, Miyake K, Furukawa K, Hayashi Y, Iguchi H, Matsuki Y, Hiramatsu R, Shimano H, Yamada N, Ohno S, Kasuga M, Noda T. PKClambda in liver mediates insulin-induced SREBP-1c expression and determines both hepatic lipid content and overall insulin sensitivity. J Clin Invest 2003; 112:935-44. [PMID: 12975478 PMCID: PMC193669 DOI: 10.1172/jci18816] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
PKClambda is implicated as a downstream effector of PI3K in insulin action. We show here that mice that lack PKClambda specifically in the liver (L-lambdaKO mice), produced with the use of the Cre-loxP system, exhibit increased insulin sensitivity as well as a decreased triglyceride content and reduced expression of the sterol regulatory element-binding protein-1c (SREBP-1c) gene in the liver. Induction of the hepatic expression of Srebp1c and of its target genes involved in fatty acid/triglyceride synthesis by fasting and refeeding or by hepatic expression of an active form of PI3K was inhibited in L-lambdaKO mice compared with that in control animals. Expression of Srebp1c induced by insulin or by active PI3K in primary cultured rat hepatocytes was inhibited by a dominant-negative form of PKClambda and was mimicked by overexpression of WT PKClambda. Restoration of PKClambda expression in the liver of L-lambdaKO mice with the use of adenovirus-mediated gene transfer corrected the metabolic abnormalities of these animals. Hepatic PKClambda is thus a determinant of hepatic lipid content and whole-body insulin sensitivity.
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Affiliation(s)
- Michihiro Matsumoto
- Department of Clinical Molecular Medicine, Division of Diabetes and Digestive and Kidney Diseases, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
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Busserolles J, Gueux E, Rock E, Demigné C, Mazur A, Rayssiguier Y. Oligofructose protects against the hypertriglyceridemic and pro-oxidative effects of a high fructose diet in rats. J Nutr 2003; 133:1903-8. [PMID: 12771337 DOI: 10.1093/jn/133.6.1903] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Recent findings indicate that in addition to its hyperlipemic effect, a high fructose diet has a pro-oxidant effect in rats compared with a starch-based diet. Oligofructose (OFS) has already been shown to decrease plasma lipids in rats. We assessed the impact of fructose on oxidative stress by supplementing a high fructose diet with OFS. Rats were fed either a high fructose diet or a starch-based diet, with or without supplementation of 10 g/100 g oligofructose for 4 wk. Regardless of the type of carbohydrate, OFS in the diet produced an enlargement of the cecum and led to a significant increase in the SCFA cecum pool. Fructose feeding was associated with significantly higher insulin plasma concentrations (+63%) in the control groups, whereas insulin plasma concentrations did not differ in rats fed the fructose diet supplemented with OFS. Plasma leptin concentration was significantly lower (approximately 50%) in the OFS-supplemented fructose group compared with the other three groups. Fructose feeding in rats also significantly increased plasma (P < 0.001) and liver (P < 0.001) triglyceride (TG) concentrations and the addition of OFS prevented the TG accumulation induced by fructose in the liver (P < 0.05) and hyperlipemia (P < 0.05). OFS consumption prevented (P < 0.05) the lower plasma vitamin E/TG ratio in rats fed the fructose diet. Control rats fed the fructose diet had high plasma TBARS values compared with rats fed the starch diet, whereas TBARS values remained unchanged when rats were supplemented with OFS. Control rats fed the fructose diet had higher TBARS urine values and higher heart tissue susceptibility to peroxidation compared with rats fed the starch diet, and this effect was significantly reduced by OFS consumption. Further studies are required to identify the mechanisms underlying the protective effect of OFS against the pro-oxidant effect of fructose. However, the potential nutritional benefits of OFS supplementation in fructose-rich diets are suggested.
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Affiliation(s)
- Jérôme Busserolles
- Centre de Recherche en Nutrition Humaine d'Auvergne, Unité des Maladies Métaboliques et Micronutriments, INRA, Theix, 63122 Saint-Genès-Champanelle, France
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Morris KL, Namey TC, Zemel MB. Effects of dietary carbohydrate on the development of obesity in heterozygous Zucker rats. J Nutr Biochem 2003; 14:32-9. [PMID: 12559475 DOI: 10.1016/s0955-2863(02)00249-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Rats carrying one copy of the fa allele are predisposed to diet-induced metabolic disturbances which contribute to hyperinsulinemia, obesity and dyslipidemia. To investigate the role of dietary carbohydrate and fat in the development of these conditions, we fed 6-week old male heterozygous (fa/+) lean rats carbohydrate-free diets containing primarily saturated fat either ad libitum or pair-fed. These diets were compared to standard chow and to a high saturated fat mixed diet containing 10% energy from sucrose for 4 weeks. The carbohydrate-free diet resulted in significantly lower circulating glucose levels compared to all other groups (p = 0.006). Weight gain was negligible in the carbohydrate free groups compared to standard diet and 10% sucrose diet (p = 0.03). This was reflected in energy efficiency which was markedly reduced (90%) in the carbohydrate-free groups compared to the other groups (p = 0.04). Corresponding changes were noted in fat pad mass. The subscapular and epididymal fat pads were increased 42% and 44%, respectively, in animals consuming the 10% sucrose diet compared to all other groups (p < 0.01). Comparable changes in fatty acid synthase (FAS) mRNA were observed in response to the carbohydrate-free diet, which resulted in a 53% decrease in adipocyte FAS mRNA (p < 0.001). Addition of 10% sucrose to the diet completely reversed this effect resulting in a 69% increase in adipocyte FAS mRNA compared to the carbohydrate-free groups (p = 0.01). Similarly, hepatic FAS mRNA was elevated by 51% and 66% in the 10% sucrose and standard diet groups respectively, compared to the carbohydrate-free groups. Therefore, diets that contain minimal carbohydrate may minimize net lipid storage and adiposity.
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Affiliation(s)
- Kristin L Morris
- Department of Nutrition, The University of Tennessee, Knoxville, TN 37996, USA
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