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He Y, Cheng X, Zhou T, Li D, Peng J, Xu Y, Huang W. β-Hydroxybutyrate as an epigenetic modifier: Underlying mechanisms and implications. Heliyon 2023; 9:e21098. [PMID: 37928021 PMCID: PMC10623287 DOI: 10.1016/j.heliyon.2023.e21098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 09/09/2023] [Accepted: 10/16/2023] [Indexed: 11/07/2023] Open
Abstract
Previous studies have found that β-Hydroxybutyrate (BHB), the main component of ketone bodies, is of physiological importance as a backup energy source during starvation or induces diabetic ketoacidosis when insulin deficiency occurs. Ketogenic diets (KD) have been used as metabolic therapy for over a hundred years, it is well known that ketone bodies and BHB not only serve as ancillary fuel substituting for glucose but also induce anti-oxidative, anti-inflammatory, and cardioprotective features via binding to several target proteins, including histone deacetylase (HDAC), or G protein-coupled receptors (GPCRs). Recent advances in epigenetics, especially novel histone post-translational modifications (HPTMs), have continuously updated our understanding of BHB, which also acts as a signal transduction molecule and modification substrate to regulate a series of epigenetic phenomena, such as histone acetylation, histone β-hydroxybutyrylation, histone methylation, DNA methylation, and microRNAs. These epigenetic events alter the activity of genes without changing the DNA structure and further participate in the pathogenesis of related diseases. This review focuses on the metabolic process of BHB and BHB-mediated epigenetics in cardiovascular diseases, diabetes and complications of diabetes, neuropsychiatric diseases, cancers, osteoporosis, liver and kidney injury, embryonic and fetal development, and intestinal homeostasis, and discusses potential molecular mechanisms, drug targets, and application prospects.
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Affiliation(s)
- Yanqiu He
- Department of Endocrinology and Metabolism, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, 646000, China
- Metabolic Vascular Diseases Key Laboratory of Sichuan Province, Luzhou, Sichuan, 646000, China
- Sichuan Clinical Research Center for Nephropathy, Luzhou, Sichuan, 646000, China
- Sichuan Clinical Research Center for Diabetes and Metabolic Diseases, Luzhou, Sichuan, 646000, China
| | - Xi Cheng
- Department of Endocrinology and Metabolism, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, 646000, China
- Metabolic Vascular Diseases Key Laboratory of Sichuan Province, Luzhou, Sichuan, 646000, China
- Sichuan Clinical Research Center for Nephropathy, Luzhou, Sichuan, 646000, China
- Sichuan Clinical Research Center for Diabetes and Metabolic Diseases, Luzhou, Sichuan, 646000, China
| | - Tingting Zhou
- Department of Endocrinology and Metabolism, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, 646000, China
- Metabolic Vascular Diseases Key Laboratory of Sichuan Province, Luzhou, Sichuan, 646000, China
- Sichuan Clinical Research Center for Nephropathy, Luzhou, Sichuan, 646000, China
- Sichuan Clinical Research Center for Diabetes and Metabolic Diseases, Luzhou, Sichuan, 646000, China
| | - Dongze Li
- Department of Endocrinology and Metabolism, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, 646000, China
- Metabolic Vascular Diseases Key Laboratory of Sichuan Province, Luzhou, Sichuan, 646000, China
- Sichuan Clinical Research Center for Nephropathy, Luzhou, Sichuan, 646000, China
- Sichuan Clinical Research Center for Diabetes and Metabolic Diseases, Luzhou, Sichuan, 646000, China
| | - Juan Peng
- Department of Rehabilitation, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, 646000, China
| | - Yong Xu
- Department of Endocrinology and Metabolism, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, 646000, China
- Metabolic Vascular Diseases Key Laboratory of Sichuan Province, Luzhou, Sichuan, 646000, China
- Sichuan Clinical Research Center for Nephropathy, Luzhou, Sichuan, 646000, China
- Sichuan Clinical Research Center for Diabetes and Metabolic Diseases, Luzhou, Sichuan, 646000, China
| | - Wei Huang
- Department of Endocrinology and Metabolism, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, 646000, China
- Metabolic Vascular Diseases Key Laboratory of Sichuan Province, Luzhou, Sichuan, 646000, China
- Sichuan Clinical Research Center for Nephropathy, Luzhou, Sichuan, 646000, China
- Sichuan Clinical Research Center for Diabetes and Metabolic Diseases, Luzhou, Sichuan, 646000, China
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Asif S, Kim RY, Fatica T, Sim J, Zhao X, Oh Y, Denoncourt A, Cheung A, Downey M, Mulvihill EE, Kim KH. Hmgcs2-mediated ketogenesis modulates high-fat diet-induced hepatosteatosis. Mol Metab 2022; 61:101494. [PMID: 35421611 PMCID: PMC9039870 DOI: 10.1016/j.molmet.2022.101494] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 04/01/2022] [Accepted: 04/04/2022] [Indexed: 12/11/2022] Open
Abstract
OBJECTIVE Aberrant ketogenesis is correlated with the degree of steatosis in NAFLD patients, and an inborn error of ketogenesis (mitochondrial HMG-CoA synthase deficiency) is commonly associated with the development of the fatty liver. Here we aimed to determine the impact of Hmgcs2-mediated ketogenesis and its modulations on the development and treatment of fatty liver disease. METHODS Loss- and gain-of-ketogenic function through in vivo and in vitro models, achieved by Hmgcs2 knockout and overexpression, respectively, were examined to investigate the role of ketogenesis in the hepatic lipid accumulation during neonatal development and the diet-induced NAFLD mouse model. RESULTS Ketogenic function was decreased in NAFLD mice with a reduction in Hmgcs2 expression. Mice lacking Hmgcs2 developed spontaneous fatty liver phenotype during postnatal development, which was rescued by a shift to a low-fat dietary composition via early weaning. Hmgcs2 heterozygous mice, which exhibited reduced ketogenic activity, were more susceptible to diet-induced NAFLD development, whereas HMGCS2 overexpression in NAFLD mice improved hepatosteatosis and glucose homeostasis. CONCLUSIONS Our study adds new knowledge to the field of ketone body metabolism and shows that Hmgcs2-mediated ketogenesis modulates hepatic lipid regulation under a fat-enriched nutritional environment. The regulation of hepatic ketogenesis may be a viable therapeutic strategy in the prevention and treatment of hepatosteatosis.
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Affiliation(s)
- Shaza Asif
- University of Ottawa Heart Institute, Ottawa, ON, K1Y 4W7, Canada; Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
| | - Ri Youn Kim
- University of Ottawa Heart Institute, Ottawa, ON, K1Y 4W7, Canada
| | - Thet Fatica
- University of Ottawa Heart Institute, Ottawa, ON, K1Y 4W7, Canada
| | - Jordan Sim
- Department of Pathology and Laboratory Medicine, The Ottawa Hospital, Ottawa, ON, K1H 8M5, Canada
| | - Xiaoling Zhao
- University of Ottawa Heart Institute, Ottawa, ON, K1Y 4W7, Canada
| | - Yena Oh
- University of Ottawa Heart Institute, Ottawa, ON, K1Y 4W7, Canada; Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
| | - Alix Denoncourt
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada; Ottawa Institute of Systems Biology, Ottawa, ON, K1H 8M5, Canada
| | - Angela Cheung
- Gastroenterology and Hepatology, Department of Medicine, The Ottawa Hospital, Ottawa, ON, K1H 8M5, Canada; The Ottawa Hospital Research Institute, Chronic Disease Program, Ottawa, ON, K1Y 4E9, Canada
| | - Michael Downey
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada; Ottawa Institute of Systems Biology, Ottawa, ON, K1H 8M5, Canada
| | - Erin E Mulvihill
- University of Ottawa Heart Institute, Ottawa, ON, K1Y 4W7, Canada; Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
| | - Kyoung-Han Kim
- University of Ottawa Heart Institute, Ottawa, ON, K1Y 4W7, Canada; Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada.
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Yi W, Sylvester E, Lian J, Deng C. Kidney plays an important role in ketogenesis induced by risperidone and voluntary exercise in juvenile female rats. Psychiatry Res 2021; 305:114196. [PMID: 34488011 DOI: 10.1016/j.psychres.2021.114196] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 07/16/2021] [Accepted: 08/28/2021] [Indexed: 11/27/2022]
Abstract
The positive role of ketone bodies in the treatment for mental disorders has been demonstrated. Ketogenesis can be triggered by not only exercise and diet but also metabolic disorders. This study aimed to explore the role of risperidone and exercise in ketogenesis. Thirty-two juvenile female Sprague Dawley rats were randomly assigned into four groups: Vehicle-Sedentary, Risperidone (0.9 mg/kg; b.i.d)-Sedentary, Vehicle-Exercise (three hours daily access to running wheels) and Risperidone-Exercise groups for four weeks. Exercise-intervention significantly ameliorated the risperidone-induced increase in white adipose mass, fasting plasma triglyceride and insulin levels. Compared to the vehicle-exercise group, the risperidone-exercise group had significantly higher plasma β-hydroxybutyrate (β-HB) level, which had a positive correlation with plasma non-esterified fatty acid levels. Risperidone-treatment upregulated expression of ketogenic key enzyme, mitochondrial 3-hydroxy-3-methyl-glutaryl-CoA synthase 2 (HMGCS2) in the kidney rather than liver. Exercise-intervention significantly enhanced renal carnitine palmitoyltransferase1A (CPT1A) expression. These results suggested that the kidney plays an important role in ketogenesis associated with risperidone and exercise. Therefore, it is important to monitor the levels of plasma ketone bodies while exercise intervention is utilized to prevent risperidone-induced metabolic disorders in young people.
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Affiliation(s)
- Weijie Yi
- Department of Nutrition and Food Hygiene, School of Public Health and Management, Binzhou Medical University, Yantai, Shandong 264003, China; Antipsychotic Research Laboratory, Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia; School of Medicine and Molecular Horizons, University of Wollongong, Wollongong, NSW, Australia
| | - Emma Sylvester
- Antipsychotic Research Laboratory, Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia; School of Medicine and Molecular Horizons, University of Wollongong, Wollongong, NSW, Australia
| | - Jiamei Lian
- Antipsychotic Research Laboratory, Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia; School of Medicine and Molecular Horizons, University of Wollongong, Wollongong, NSW, Australia
| | - Chao Deng
- Antipsychotic Research Laboratory, Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia; School of Medicine and Molecular Horizons, University of Wollongong, Wollongong, NSW, Australia.
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Labanca E, Bizzotto J, Sanchis P, Anselmino N, Yang J, Shepherd PDA, Paez A, Antico-Arciuch V, Lage-Vickers S, Hoang AG, Tang X, Raso MG, Titus M, Efstathiou E, Cotignola J, Araujo J, Logothetis C, Vazquez E, Navone N, Gueron G. Prostate cancer castrate resistant progression usage of non-canonical androgen receptor signaling and ketone body fuel. Oncogene 2021; 40:6284-6298. [PMID: 34584218 PMCID: PMC8566229 DOI: 10.1038/s41388-021-02008-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 08/25/2021] [Accepted: 09/06/2021] [Indexed: 02/08/2023]
Abstract
Prostate cancer (PCa) that progresses after androgen deprivation therapy (ADT) remains incurable. The underlying mechanisms that account for the ultimate emergence of resistance to ADT, progressing to castrate-resistant prostate cancer (CRPC), include those that reactivate androgen receptor (AR), or those that are entirely independent or cooperate with androgen signaling to underlie PCa progression. The intricacy of metabolic pathways associated with PCa progression spurred us to develop a metabolism-centric analysis to assess the metabolic shift occurring in PCa that progresses with low AR expression. We used PCa patient-derived xenografts (PDXs) to assess the metabolic changes after castration of tumor-bearing mice and subsequently confirmed main findings in human donor tumor that progressed after ADT. We found that relapsed tumors had a significant increase in fatty acids and ketone body (KB) content compared with baseline. We confirmed that critical ketolytic enzymes (ACAT1, OXCT1, BDH1) were dysregulated after castrate-resistant progression. Further, these enzymes are increased in the human donor tissue after progressing to ADT. In an in silico approach, increased ACAT1, OXCT1, BDH1 expression was also observed for a subset of PCa patients that relapsed with low AR and ERG (ETS-related gene) expression. Further, expression of these factors was also associated with decreased time to biochemical relapse and decreased progression-free survival. Our studies reveal the key metabolites fueling castration resistant progression in the context of a partial or complete loss of AR dependence.
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Affiliation(s)
- Estefania Labanca
- grid.240145.60000 0001 2291 4776Department of Genitourinary Medical Oncology and the David H. Koch Center for Applied Research of Genitourinary Cancers, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
| | - Juan Bizzotto
- grid.7345.50000 0001 0056 1981Laboratorio de Inflamación y Cáncer, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina ,grid.7345.50000 0001 0056 1981CONICET-Universidad de Buenos Aires. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Buenos Aires, CP1428 Argentina
| | - Pablo Sanchis
- grid.7345.50000 0001 0056 1981Laboratorio de Inflamación y Cáncer, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina ,grid.7345.50000 0001 0056 1981CONICET-Universidad de Buenos Aires. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Buenos Aires, CP1428 Argentina
| | - Nicolas Anselmino
- grid.240145.60000 0001 2291 4776Department of Genitourinary Medical Oncology and the David H. Koch Center for Applied Research of Genitourinary Cancers, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
| | - Jun Yang
- grid.240145.60000 0001 2291 4776Department of Genitourinary Medical Oncology and the David H. Koch Center for Applied Research of Genitourinary Cancers, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
| | - Peter D. A. Shepherd
- grid.240145.60000 0001 2291 4776Department of Genitourinary Medical Oncology and the David H. Koch Center for Applied Research of Genitourinary Cancers, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
| | - Alejandra Paez
- grid.7345.50000 0001 0056 1981Laboratorio de Inflamación y Cáncer, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina ,grid.7345.50000 0001 0056 1981CONICET-Universidad de Buenos Aires. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Buenos Aires, CP1428 Argentina ,grid.7345.50000 0001 0056 1981Unidad de Transferencia Genética, Instituto de Oncología “Angel H Roffo”, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Valeria Antico-Arciuch
- grid.7345.50000 0001 0056 1981Laboratorio de Inflamación y Cáncer, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina ,grid.7345.50000 0001 0056 1981CONICET-Universidad de Buenos Aires. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Buenos Aires, CP1428 Argentina
| | - Sofia Lage-Vickers
- grid.7345.50000 0001 0056 1981Laboratorio de Inflamación y Cáncer, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina ,grid.7345.50000 0001 0056 1981CONICET-Universidad de Buenos Aires. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Buenos Aires, CP1428 Argentina
| | - Anh G. Hoang
- grid.240145.60000 0001 2291 4776Department of Genitourinary Medical Oncology and the David H. Koch Center for Applied Research of Genitourinary Cancers, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
| | - Ximing Tang
- grid.240145.60000 0001 2291 4776Department of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
| | - Maria Gabriela Raso
- grid.240145.60000 0001 2291 4776Department of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
| | - Mark Titus
- grid.240145.60000 0001 2291 4776Department of Genitourinary Medical Oncology and the David H. Koch Center for Applied Research of Genitourinary Cancers, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
| | - Eleni Efstathiou
- grid.240145.60000 0001 2291 4776Department of Genitourinary Medical Oncology and the David H. Koch Center for Applied Research of Genitourinary Cancers, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
| | - Javier Cotignola
- grid.7345.50000 0001 0056 1981Laboratorio de Inflamación y Cáncer, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina ,grid.7345.50000 0001 0056 1981CONICET-Universidad de Buenos Aires. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Buenos Aires, CP1428 Argentina
| | - John Araujo
- grid.240145.60000 0001 2291 4776Department of Genitourinary Medical Oncology and the David H. Koch Center for Applied Research of Genitourinary Cancers, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
| | - Christopher Logothetis
- grid.240145.60000 0001 2291 4776Department of Genitourinary Medical Oncology and the David H. Koch Center for Applied Research of Genitourinary Cancers, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
| | - Elba Vazquez
- grid.7345.50000 0001 0056 1981Laboratorio de Inflamación y Cáncer, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina ,grid.7345.50000 0001 0056 1981CONICET-Universidad de Buenos Aires. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Buenos Aires, CP1428 Argentina
| | - Nora Navone
- grid.240145.60000 0001 2291 4776Department of Genitourinary Medical Oncology and the David H. Koch Center for Applied Research of Genitourinary Cancers, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
| | - Geraldine Gueron
- grid.7345.50000 0001 0056 1981Laboratorio de Inflamación y Cáncer, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina ,grid.7345.50000 0001 0056 1981CONICET-Universidad de Buenos Aires. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Buenos Aires, CP1428 Argentina
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Modes of genetic adaptations underlying functional innovations in the rumen. SCIENCE CHINA-LIFE SCIENCES 2020; 64:1-21. [PMID: 33165812 DOI: 10.1007/s11427-020-1828-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 09/29/2020] [Indexed: 10/23/2022]
Abstract
The rumen is the hallmark organ of ruminants and hosts a diverse ecosystem of microorganisms that facilitates efficient digestion of plant fibers. We analyzed 897 transcriptomes from three Cetartiodactyla lineages: ruminants, camels and cetaceans, as well as data from ruminant comparative genomics and functional assays to explore the genetic basis of rumen functional innovations. We identified genes with relatively high expression in the rumen, of which many appeared to be recruited from other tissues. These genes show functional enrichment in ketone body metabolism, regulation of microbial community, and epithelium absorption, which are the most prominent biological processes involved in rumen innovations. Several modes of genetic change underlying rumen functional innovations were uncovered, including coding mutations, genes newly evolved, and changes of regulatory elements. We validated that the key ketogenesis rate-limiting gene (HMGCS2) with five ruminant-specific mutations was under positive selection and exhibits higher synthesis activity than those of other mammals. Two newly evolved genes (LYZ1 and DEFB1) are resistant to Gram-positive bacteria and thereby may regulate microbial community equilibrium. Furthermore, we confirmed that the changes of regulatory elements accounted for the majority of rumen gene recruitment. These results greatly improve our understanding of rumen evolution and organ evo-devo in general.
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Wallenius V, Elias E, Elebring E, Haisma B, Casselbrant A, Larraufie P, Spak E, Reimann F, le Roux CW, Docherty NG, Gribble FM, Fändriks L. Suppression of enteroendocrine cell glucagon-like peptide (GLP)-1 release by fat-induced small intestinal ketogenesis: a mechanism targeted by Roux-en-Y gastric bypass surgery but not by preoperative very-low-calorie diet. Gut 2020; 69:1423-1431. [PMID: 31753852 PMCID: PMC7347417 DOI: 10.1136/gutjnl-2019-319372] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 11/04/2019] [Accepted: 11/06/2019] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Food intake normally stimulates release of satiety and insulin-stimulating intestinal hormones, such as glucagon-like peptide (GLP)-1. This response is blunted in obese insulin resistant subjects, but is rapidly restored following Roux-en-Y gastric bypass (RYGB) surgery. We hypothesised this to be a result of the metabolic changes taking place in the small intestinal mucosa following the anatomical rearrangement after RYGB surgery, and aimed at identifying such mechanisms. DESIGN Jejunal mucosa biopsies from patients undergoing RYGB surgery were retrieved before and after very-low calorie diet, at time of surgery and 6 months postoperatively. Samples were analysed by global protein expression analysis and Western blotting. Biological functionality of these findings was explored in mice and enteroendocrine cells (EECs) primary mouse jejunal cell cultures. RESULTS The most prominent change found after RYGB was decreased jejunal expression of the rate-limiting ketogenic enzyme mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase (mHMGCS), corroborated by decreased ketone body levels. In mice, prolonged high-fat feeding induced the expression of mHMGCS and functional ketogenesis in jejunum. The effect of ketone bodies on gut peptide secretion in EECs showed a ∼40% inhibition of GLP-1 release compared with baseline. CONCLUSION Intestinal ketogenesis is induced by high-fat diet and inhibited by RYGB surgery. In cell culture, ketone bodies inhibited GLP-1 release from EECs. Thus, we suggest that this may be a mechanism by which RYGB can remove the inhibitory effect of ketone bodies on EECs, thereby restituting the responsiveness of EECs resulting in increased meal-stimulated levels of GLP-1 after surgery.
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Affiliation(s)
- Ville Wallenius
- Department of Gastrosurgical Research and Education, Institute of Clinical Sciences, Sahlgrenska Academy, Sahlgrenska University Hospital/Sahlgrenska, University of Gothenburg, Gothenburg, Sweden .,Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, Sahlgrenska University Hospital/Östra, University of Gothenburg, Gothenburg, Sweden
| | - Erik Elias
- Department of Gastrosurgical Research and Education, Institute of Clinical Sciences, Sahlgrenska Academy, Sahlgrenska University Hospital/Sahlgrenska, University of Gothenburg, Gothenburg, Sweden,Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, Sahlgrenska University Hospital/Sahlgrenska, University of Gothenburg, Gothenburg, Sweden
| | - Erik Elebring
- Department of Gastrosurgical Research and Education, Institute of Clinical Sciences, Sahlgrenska Academy, Sahlgrenska University Hospital/Sahlgrenska, University of Gothenburg, Gothenburg, Sweden
| | - Bauke Haisma
- Metabolic Research Laboratories, University of Cambridge, Cambridge, UK
| | - Anna Casselbrant
- Department of Gastrosurgical Research and Education, Institute of Clinical Sciences, Sahlgrenska Academy, Sahlgrenska University Hospital/Sahlgrenska, University of Gothenburg, Gothenburg, Sweden
| | - Pierre Larraufie
- Metabolic Research Laboratories, University of Cambridge, Cambridge, UK
| | - Emma Spak
- Department of Gastrosurgical Research and Education, Institute of Clinical Sciences, Sahlgrenska Academy, Sahlgrenska University Hospital/Sahlgrenska, University of Gothenburg, Gothenburg, Sweden
| | - Frank Reimann
- Metabolic Research Laboratories, University of Cambridge, Cambridge, UK
| | - Carel W le Roux
- Diabetes Complications Research Centre, Conway Institute, University College of Dublin, Dublin, Ireland
| | - Neil G Docherty
- Diabetes Complications Research Centre, Conway Institute, University College of Dublin, Dublin, Ireland
| | - Fiona M Gribble
- Metabolic Research Laboratories, University of Cambridge, Cambridge, UK
| | - Lars Fändriks
- Department of Gastrosurgical Research and Education, Institute of Clinical Sciences, Sahlgrenska Academy, Sahlgrenska University Hospital/Sahlgrenska, University of Gothenburg, Gothenburg, Sweden
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7
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Karwi QG, Biswas D, Pulinilkunnil T, Lopaschuk GD. Myocardial Ketones Metabolism in Heart Failure. J Card Fail 2020; 26:998-1005. [PMID: 32442517 DOI: 10.1016/j.cardfail.2020.04.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 03/18/2020] [Accepted: 04/09/2020] [Indexed: 02/06/2023]
Abstract
Ketone bodies can become a major source of adenosine triphosphate production during stress to maintain bioenergetic homeostasis in the brain, heart, and skeletal muscles. In the normal heart, ketone bodies contribute from 10% to 15% of the cardiac adenosine triphosphate production, although their contribution during pathologic stress is still not well-characterized and currently represents an exciting area of cardiovascular research. This review focuses on the mechanisms that regulate circulating ketone levels under physiologic and pathologic conditions and how this impacts cardiac ketone metabolism. We also review the current understanding of the role of augmented ketone metabolism as an adaptive response in different types and stages of heart failure. This analysis includes the emerging experimental and clinical evidence of the potential favorable effects of boosting ketone metabolism in the failing heart and the possible mechanisms of action through which these interventions may mediate their cardioprotective effects. We also critically appraise the emerging data from animal and human studies which characterize the role of ketones in mediating the cardioprotection established by the new class of antidiabetic drugs, namely sodium-glucose co-transporter inhibitors.
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Affiliation(s)
- Qutuba G Karwi
- Cardiovascular Research Centre, University of Alberta, Edmonton, Alberta, Canada; Department of Pharmacology, College of Medicine, University of Diyala, Diyala, Iraq.
| | - Dipsikha Biswas
- Department of Biochemistry and Molecular Biology, Dalhousie Medicine New Brunswick, Dalhousie University, Saint John, New Brunswick, Canada.
| | - Thomas Pulinilkunnil
- Department of Biochemistry and Molecular Biology, Dalhousie Medicine New Brunswick, Dalhousie University, Saint John, New Brunswick, Canada
| | - Gary D Lopaschuk
- Cardiovascular Research Centre, University of Alberta, Edmonton, Alberta, Canada
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Xiao C, Stahel P, Nahmias A, Lewis GF. Emerging Role of Lymphatics in the Regulation of Intestinal Lipid Mobilization. Front Physiol 2020; 10:1604. [PMID: 32063861 PMCID: PMC7000543 DOI: 10.3389/fphys.2019.01604] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 12/20/2019] [Indexed: 12/21/2022] Open
Abstract
Intestinal handling of dietary triglycerides has important implications for health and disease. Following digestion in the intestinal lumen, absorption, and re-esterification of fatty acids and monoacylglycerols in intestinal enterocytes, triglycerides are packaged into lipoprotein particles (chylomicrons) for secretion or into cytoplasmic lipid droplets for transient or more prolonged storage. Despite the recognition of prolonged retention of triglycerides in the post-absorptive phase and subsequent release from the intestine in chylomicron particles, the underlying regulatory mechanisms remain poorly understood. Chylomicron secretion involves multiple steps, including intracellular assembly and post-assembly transport through cellular organelles, the lamina propria, and the mesenteric lymphatics before being released into the circulation. Contrary to the long-held view that the intestinal lymphatic vasculature acts mainly as a passive conduit, it is increasingly recognized to play an active and regulatory role in the rate of chylomicron release into the circulation. Here, we review the latest advances in understanding the role of lymphatics in intestinal lipid handling and chylomicron secretion. We highlight emerging evidence that oral glucose and the gut hormone glucagon-like peptide-2 mobilize retained enteral lipid by differing mechanisms to promote the secretion of chylomicrons via glucose possibly by mobilizing cytoplasmic lipid droplets and via glucagon-like peptide-2 possibly by targeting post-enterocyte secretory mechanisms. We discuss other potential regulatory factors that are the focus of ongoing and future research. Regulation of lymphatic pumping and function is emerging as an area of great interest in our understanding of the integrated absorption of dietary fat and chylomicron secretion and potential implications for whole-body metabolic health.
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Affiliation(s)
- Changting Xiao
- Department of Medicine and Department of Physiology, Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, Canada
| | - Priska Stahel
- Department of Medicine and Department of Physiology, Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, Canada
| | - Avital Nahmias
- Department of Medicine and Department of Physiology, Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, Canada
| | - Gary F Lewis
- Department of Medicine and Department of Physiology, Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, Canada
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HMGCS2 Mediates Ketone Production and Regulates the Proliferation and Metastasis of Hepatocellular Carcinoma. Cancers (Basel) 2019; 11:cancers11121876. [PMID: 31779269 PMCID: PMC6966636 DOI: 10.3390/cancers11121876] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 11/22/2019] [Accepted: 11/22/2019] [Indexed: 12/24/2022] Open
Abstract
Hepatocellular carcinoma (HCC) is the most common primary malignant tumor worldwide; however, the traditional therapeutic approaches and survival rates are still limited. To improve current therapies, it is necessary to investigate the molecular mechanisms underlying liver cancer and to identify potential therapeutic targets. The aims of this study were to verify the mechanisms and therapeutic potential of the ketogenesis rate-limiting enzyme 3-Hydroxymethylglutaryl-CoA synthase 2 (HMGCS2) in HCC. Immunohistochemical staining of human liver disease tissue arrays showed that HMGCS2 is abundantly expressed in normal liver tissues but is downregulated in cirrhosis and HCC tissues. In HCC patients, lower HMGCS2 expression was correlated with higher pathological grades and clinical stages. In our investigation of the molecular mechanisms of HMGCS2 in HCC, we showed that knockdown of HMGCS2 decreased ketone production, which promoted cell proliferation, cell migration, and xenograft tumorigenesis by enhancing c-Myc/cyclinD1 and EMT signaling and by suppressing the caspase-dependent apoptosis pathway. Ketone body treatment reduced the proliferation- and migration-promoting effects of HMGCS2 knockdown in cells. In contrast, HMGCS2 overexpression increased the intracellular ketone level and inhibited cell proliferation, cell migration, and xenograft tumorigenesis. Finally, ketogenic diet administration significantly inhibited liver cancer cell growth in mice. Our studies highlight the potential therapeutic strategy of targeting HMGCS2-mediated ketogenesis in liver cancer.
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10
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Wan S, Xi M, Zhao HB, Hua W, Liu YL, Zhou YL, Zhuo YJ, Liu ZZ, Cai ZD, Wan YP, Zhong WD. HMGCS2 functions as a tumor suppressor and has a prognostic impact in prostate cancer. Pathol Res Pract 2019; 215:152464. [DOI: 10.1016/j.prp.2019.152464] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Revised: 05/09/2019] [Accepted: 05/21/2019] [Indexed: 12/28/2022]
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11
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Singh S, McDonough CW, Gong Y, Alghamdi WA, Arwood MJ, Bargal SA, Dumeny L, Li WY, Mehanna M, Stockard B, Yang G, de Oliveira FA, Fredette NC, Shahin MH, Bailey KR, Beitelshees AL, Boerwinkle E, Chapman AB, Gums JG, Turner ST, Cooper-DeHoff RM, Johnson JA. Genome Wide Association Study Identifies the HMGCS2 Locus to be Associated With Chlorthalidone Induced Glucose Increase in Hypertensive Patients. J Am Heart Assoc 2018. [PMID: 29523524 PMCID: PMC5907544 DOI: 10.1161/jaha.117.007339] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Background Thiazide and thiazide‐like diuretics are first‐line medications for treating uncomplicated hypertension. However, their use has been associated with adverse metabolic events, including hyperglycemia and incident diabetes mellitus, with incompletely understood mechanisms. Our goal was to identify genomic variants associated with thiazide‐like diuretic/chlorthalidone‐induced glucose change. Methods and Results Genome‐wide analysis of glucose change after treatment with chlorthalidone was performed by race among the white (n=175) and black (n=135) participants from the PEAR‐2 (Pharmacogenomic Evaluation of Antihypertensive Responses‐2). Single‐nucleotide polymorphisms with P<5×10−8 were further prioritized using in silico analysis based on their expression quantitative trait loci function. Among blacks, an intronic single‐nucleotide polymorphism (rs9943291) in the HMGCS2 was associated with increase in glucose levels following chlorthalidone treatment (ß=12.5; P=4.17×10−8). G‐allele carriers of HMGCS2 had higher glucose levels (glucose change=+16.29 mg/dL) post chlorthalidone treatment compared with noncarriers of G allele (glucose change=+2.80 mg/dL). This association was successfully replicated in an independent replication cohort of hydrochlorothiazide‐treated participants from the PEAR study (ß=5.54; P=0.023). A meta‐analysis of the 2 studies was performed by race in Meta‐Analysis Helper, where this single‐nucleotide polymorphism, rs9943291, was genome‐wide significant with a meta‐analysis P value of 3.71×10−8. HMGCS2, a part of the HMG‐CoA synthase family, is important for ketogenesis and cholesterol synthesis pathways that are essential in glucose homeostasis. Conclusions These results suggest that HMGCS2 is a promising candidate gene involved in chlorthalidone and Hydrochlorothiazide (HCTZ)‐induced glucose change. This may provide insights into the mechanisms involved in thiazide‐induced hyperglycemia that may ultimately facilitate personalized approaches to antihypertensive selection for hypertension treatment. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifiers: NCT00246519 and NCT01203852.
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Affiliation(s)
- Sonal Singh
- Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, University of Florida, Gainesville, FL
| | - Caitrin W McDonough
- Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, University of Florida, Gainesville, FL
| | - Yan Gong
- Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, University of Florida, Gainesville, FL
| | - Wael A Alghamdi
- Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, University of Florida, Gainesville, FL
| | - Meghan J Arwood
- Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, University of Florida, Gainesville, FL
| | - Salma A Bargal
- Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, University of Florida, Gainesville, FL
| | - Leanne Dumeny
- Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, University of Florida, Gainesville, FL
| | - Wen-Yi Li
- Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, University of Florida, Gainesville, FL
| | - Mai Mehanna
- Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, University of Florida, Gainesville, FL
| | - Bradley Stockard
- Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, University of Florida, Gainesville, FL
| | - Guang Yang
- Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, University of Florida, Gainesville, FL
| | - Felipe A de Oliveira
- Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, University of Florida, Gainesville, FL
| | - Natalie C Fredette
- Department of Pathology, Center of Regenerative Medicine, University of Florida, Gainesville, FL
| | - Mohamed H Shahin
- Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, University of Florida, Gainesville, FL
| | - Kent R Bailey
- Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic, Rochester, MN
| | | | - Eric Boerwinkle
- Human Genetics and Institute of Molecular Medicine, University of Texas Health Science Center, Houston, TX
| | | | - John G Gums
- Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, University of Florida, Gainesville, FL
| | - Stephen T Turner
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN
| | - Rhonda M Cooper-DeHoff
- Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, University of Florida, Gainesville, FL .,Division of Cardiovascular Medicine, Department of Medicine, University of Florida, Gainesville, FL
| | - Julie A Johnson
- Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, University of Florida, Gainesville, FL.,Division of Cardiovascular Medicine, Department of Medicine, University of Florida, Gainesville, FL
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12
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miR-107-mediated decrease of HMGCS2 indicates poor outcomes and promotes cell migration in hepatocellular carcinoma. Int J Biochem Cell Biol 2017; 91:53-59. [PMID: 28867541 DOI: 10.1016/j.biocel.2017.08.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 08/23/2017] [Accepted: 08/24/2017] [Indexed: 01/02/2023]
Abstract
Mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase (HMGCS2) has been implicated in human cancers, but its role and clinical significance in hepatocellular carcinoma (HCC) remain unknown. Here, we show that HMGCS2 is downregulated and exhibits antimetastatic potential in HCC. Low expression of HMGCS2 was associated with poor tumor differentiation, vascular invasion and worse overall and disease-free survivals in two independent cohorts consisting of 743 cases. In vitro data demonstrated HMGCS2 overexpression suppressed, whereas HMGCS2 silence promoted HCC cell migration via Epithelial-Mesenchymal Transition (EMT) process and the activation of ERK/c-Jun signaling pathway. Inhibition of ERK phosphorylation by PD098059 markedly attenuated the malignant phenotypes mediated by HMGCS2 siRNA. Furthermore, miR-107 was identified as an upstream regulator of HMGCS2 via directly targeting the 3'-UTR of HMGCS2 mRNA. Collectively, our findings suggest HMGCS2 serve as a promising prognostic biomarker and exert anti-tumor activity towards HCC, and therefore provide a potential target for HCC clinical intervention.
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Abstract
Various mechanisms in the mammalian body provide resilience against food deprivation and dietary stress. The ketone body β-hydroxybutyrate (BHB) is synthesized in the liver from fatty acids and represents an essential carrier of energy from the liver to peripheral tissues when the supply of glucose is too low for the body's energetic needs, such as during periods of prolonged exercise, starvation, or absence of dietary carbohydrates. In addition to its activity as an energetic metabolite, BHB is increasingly understood to have cellular signaling functions. These signaling functions of BHB broadly link the outside environment to epigenetic gene regulation and cellular function, and their actions may be relevant to a variety of human diseases as well as human aging.
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Affiliation(s)
- John C Newman
- Buck Institute for Research on Aging, Novato, California 94945; ,
- Gladstone Institutes, San Francisco, California 94158
- Division of Geriatrics, University of California, San Francisco, California 94143
| | - Eric Verdin
- Buck Institute for Research on Aging, Novato, California 94945; ,
- Gladstone Institutes, San Francisco, California 94158
- Division of Geriatrics, University of California, San Francisco, California 94143
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14
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Lima GC, Vieira VCC, Cazarin CBB, Ribeiro RDR, Junior SB, de Albuquerque CL, Vidal RO, Netto CC, Yamada ÁT, Augusto F, Maróstica Junior MR. Fructooligosaccharide intake promotes epigenetic changes in the intestinal mucosa in growing and ageing rats. Eur J Nutr 2017; 57:1499-1510. [PMID: 28324207 DOI: 10.1007/s00394-017-1435-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 03/06/2017] [Indexed: 01/16/2023]
Abstract
PURPOSE The aim of this study was to investigate the relationship between fructooligosaccharide (FOS) intake at different life stages of Wistar rats and its stimulatory effects on intestinal parameters. METHODS Recently weaned and ageing female rats were divided into growing and ageing treatments, which were fed diets that partially replaced sucrose with FOS for 12 weeks. RESULTS Dietary FOS intake induced a significant increase in the numbers of Bifidobacterium and Lactobacillus in growing rats. FOS intake was associated with increased butyric acid levels and a reduced pH of the caecal contents at both ages. Differential gene expression patterns were observed by microarray analysis of growing and ageing animals fed the FOS diet. A total of 133 genes showed detectable changes in expression in the growing rats, while there were only 19 gene expression changes in ageing rats fed with FOS. CONCLUSION These results suggest that dietary FOS intake may be beneficial for some parameters of intestinal health in growing rats.
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Affiliation(s)
| | | | | | | | | | | | - Ramon Oliveira Vidal
- Sainte-Justine University Hospital Center, Université de Montreal, Montreal, Canada
| | - Claudia Cardoso Netto
- Department of Biochemistry, Biological Sciences and Health Center, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - Fabio Augusto
- Institute of Chemistry, University of Campinas, Campinas, São Paulo, Brazil
| | - Mário Roberto Maróstica Junior
- School of Food Engineering, University of Campinas, Campinas, São Paulo, Brazil. .,Laboratório de Nutrição e Metabolismo-Departamento de Alimentos e Nutrição, Faculdade de Engenharia de Alimentos, Universidade Estadual de Campinas, R. Monteiro Lobato 80, Campinas, SP, 13083-862, Brazil.
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15
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Abstract
Ketone body metabolism is a central node in physiological homeostasis. In this review, we discuss how ketones serve discrete fine-tuning metabolic roles that optimize organ and organism performance in varying nutrient states and protect from inflammation and injury in multiple organ systems. Traditionally viewed as metabolic substrates enlisted only in carbohydrate restriction, observations underscore the importance of ketone bodies as vital metabolic and signaling mediators when carbohydrates are abundant. Complementing a repertoire of known therapeutic options for diseases of the nervous system, prospective roles for ketone bodies in cancer have arisen, as have intriguing protective roles in heart and liver, opening therapeutic options in obesity-related and cardiovascular disease. Controversies in ketone metabolism and signaling are discussed to reconcile classical dogma with contemporary observations.
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Affiliation(s)
- Patrycja Puchalska
- Center for Metabolic Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute, Orlando, FL 32827, USA
| | - Peter A Crawford
- Center for Metabolic Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute, Orlando, FL 32827, USA.
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16
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Stenblom EL, Egecioglu E, Montelius C, Ramachandran D, Bonn B, Weström B, Mansouri A, Langhans W, Erlanson-Albertsson C. Dietary thylakoids reduce visceral fat mass and increase expression of genes involved in intestinal fatty acid oxidation in high-fat fed rats. Am J Physiol Regul Integr Comp Physiol 2016; 311:R618-27. [PMID: 27488889 DOI: 10.1152/ajpregu.00212.2016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 07/29/2016] [Indexed: 11/22/2022]
Abstract
Thylakoids reduce body weight gain and body fat accumulation in rodents. This study investigated whether an enhanced oxidation of dietary fat-derived fatty acids in the intestine contributes to the thylakoid effects. Male Sprague-Dawley rats were fed a high-fat diet with (n = 8) or without thylakoids (n = 8) for 2 wk. Body weight, food intake, and body fat were measured, and intestinal mucosa was collected and analyzed. Quantitative real-time PCR was used to measure gene expression levels of key enzymes involved in fatty acid transport, fatty acid oxidation, and ketogenesis. Another set of thylakoid-treated (n = 10) and control rats (n = 10) went through indirect calorimetry. In the first experiment, thylakoid-treated rats (n = 8) accumulated 25% less visceral fat than controls. Furthermore, fatty acid translocase (Fat/Cd36), carnitine palmitoyltransferase 1a (Cpt1a), and mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase 2 (Hmgcs2) genes were upregulated in the jejunum of the thylakoid-treated group. In the second experiment, thylakoid-treated rats (n = 10) gained 17.5% less weight compared with controls and their respiratory quotient was lower, 0.86 compared with 0.91. Thylakoid-intake resulted in decreased food intake and did not cause steatorrhea. These results suggest that thylakoids stimulated intestinal fatty acid oxidation and ketogenesis, resulting in an increased ability of the intestine to handle dietary fat. The increased fatty acid oxidation and the resulting reduction in food intake may contribute to the reduced fat accumulation in thylakoid-treated animals.
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Affiliation(s)
- Eva-Lena Stenblom
- Department of Experimental Medical Science, Appetite Regulation Unit, Faculty of Medicine, Lund University, Lund, Sweden
| | - Emil Egecioglu
- Department of Experimental Medical Science, Appetite Regulation Unit, Faculty of Medicine, Lund University, Lund, Sweden
| | - Caroline Montelius
- Department of Experimental Medical Science, Appetite Regulation Unit, Faculty of Medicine, Lund University, Lund, Sweden
| | | | - Britta Bonn
- AstraZeneca, R&D Gothenburg, Mölndal, Sweden; and
| | - Björn Weström
- Department of Biology, Lund University, Lund, Sweden
| | - Abdelhak Mansouri
- Physiology and Behavior Laboratory, ETH Zürich, Schwerzenbach, Switzerland
| | - Wolfgang Langhans
- Physiology and Behavior Laboratory, ETH Zürich, Schwerzenbach, Switzerland
| | - Charlotte Erlanson-Albertsson
- Department of Experimental Medical Science, Appetite Regulation Unit, Faculty of Medicine, Lund University, Lund, Sweden;
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Mansouri A, Langhans W. Enterocyte-afferent nerve interactions in dietary fat sensing. Diabetes Obes Metab 2014; 16 Suppl 1:61-7. [PMID: 25200298 DOI: 10.1111/dom.12339] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 05/07/2014] [Indexed: 12/15/2022]
Abstract
The central nervous system (CNS) constantly monitors nutrient availability in the body and, in particular, in the gastrointestinal (GI) tract to regulate nutrient and energy homeostasis. Extrinsic parasympathetic and sympathetic nerves are crucial for CNS nutrient sensing in the GI tract. These extrinsic afferent nerves detect the nature and amount of nutrients present in the GI tract and relay the information to the brain, which controls energy intake and expenditure accordingly. Dietary fat and fatty acids are sensed through various direct and indirect mechanisms. These sensing processes involve the binding of fatty acids to specific G protein-coupled receptors expressed either on the afferent nerve fibres or on the surface of enteroendocrine cells that release gut peptides, which themselves can modulate afferent nerve activity through their cognate receptors or have endocrine effects directly on the brain. Further dietary fat sensing mechanisms that are related to enterocyte fat handling and metabolism involve the release of several possible chemical mediators such as fatty acid ethanolamides or apolipoprotein A-IV. We here present evidence for yet another mechanism that may be based on ketone bodies resulting from enterocyte oxidation of dietary fat-derived fatty acids. The presently available evidence suggests that sympathetic rather than vagal afferents are involved, but further experiments are necessary to critically examine this concept.
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Affiliation(s)
- A Mansouri
- Physiology and Behaviour Laboratory, ETH Zurich, Schwerzenbach, Switzerland
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18
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Newman JC, Verdin E. Ketone bodies as signaling metabolites. Trends Endocrinol Metab 2014; 25:42-52. [PMID: 24140022 PMCID: PMC4176946 DOI: 10.1016/j.tem.2013.09.002] [Citation(s) in RCA: 640] [Impact Index Per Article: 64.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 09/14/2013] [Accepted: 09/17/2013] [Indexed: 12/13/2022]
Abstract
Traditionally, the ketone body β-hydroxybutyrate (βOHB) has been looked upon as a carrier of energy from liver to peripheral tissues during fasting or exercise. However, βOHB also signals via extracellular receptors and acts as an endogenous inhibitor of histone deacetylases (HDACs). These recent findings support a model in which βOHB functions to link the environment, in this case the diet, and gene expression via chromatin modifications. We review the regulation and functions of ketone bodies, the relationship between ketone bodies and calorie restriction, and the implications of HDAC inhibition by the ketone body βOHB in the modulation of metabolism and in diseases of aging.
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Affiliation(s)
- John C Newman
- Gladstone Institutes and University of California San Francisco, 1650 Owens Street, San Francisco, CA 94158, USA
| | - Eric Verdin
- Gladstone Institutes and University of California San Francisco, 1650 Owens Street, San Francisco, CA 94158, USA.
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Karimian Azari E, Leitner C, Jaggi T, Langhans W, Mansouri A. Possible role of intestinal fatty acid oxidation in the eating-inhibitory effect of the PPAR-α agonist Wy-14643 in high-fat diet fed rats. PLoS One 2013; 8:e74869. [PMID: 24069361 PMCID: PMC3775792 DOI: 10.1371/journal.pone.0074869] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 08/09/2013] [Indexed: 12/21/2022] Open
Abstract
PPAR-α plays a key role in lipid metabolism; it enhances fatty acid oxidation (FAO) and ketogenesis. Pharmacological PPAR-α activation improves insulin sensitivity and reduces food intake, but its mechanisms of action remain unknown. We here report that intraperitoneal (IP) administration of the PPAR-α agonist Wy-14643 (40 mg/kg BW) reduced food intake in adult male rats fed a high-fat diet (HFD, 49% of the energy) mainly through an increase in the latency to eat after injection, and without inducing a conditioned taste avoidance. Also, IP administered Wy-14643 caused an acute (the first 60 min) decrease in the respiratory quotient (RQ) and an increase in hepatic portal vein β-hydroxybutyrate level (at 35 min) without affecting plasma non-esterified fatty acids. Given the known stimulatory effect of PPAR-α on FAO and ketogenesis, we measured the protein expression level of carnitine palmitoyltransferase-1 (CPT 1A) and mitochondrial 3-hydroxy-3-methylglutaryl-coenzyme A synthase (HMG-CoAS2), two key enzymes for FAO and ketogenesis, respectively, in liver, duodenum and jejunum. Wy-14643 induced a significant increase in the expression of CPT 1A in the jejunum and duodenum and of HMG-CoAS2 in the jejunum, but neither CPT 1A nor HMG-CoAS2 expression was increased in the liver. The induction of CPT 1A and HMG-CoAS2 expression was associated with a decrease in the lipid droplet content selectively in the jejunum. Our findings indicate that Wy-14643 stimulates FAO and ketogenesis in the intestine, in particular in the jejunum, rather than in the liver, thus supporting the hypothesis that PPAR-α activation inhibits eating by stimulating intestinal FAO.
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Affiliation(s)
| | - Claudia Leitner
- Physiology and Behavior Laboratory, ETH Zurich, Schwerzenbach, Switzerland
| | - Thomas Jaggi
- Physiology and Behavior Laboratory, ETH Zurich, Schwerzenbach, Switzerland
| | - Wolfgang Langhans
- Physiology and Behavior Laboratory, ETH Zurich, Schwerzenbach, Switzerland
| | - Abdelhak Mansouri
- Physiology and Behavior Laboratory, ETH Zurich, Schwerzenbach, Switzerland
- * E-mail:
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20
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Schober G, Arnold M, Birtles S, Buckett LK, Pacheco-López G, Turnbull AV, Langhans W, Mansouri A. Diacylglycerol acyltransferase-1 inhibition enhances intestinal fatty acid oxidation and reduces energy intake in rats. J Lipid Res 2013; 54:1369-84. [PMID: 23449193 DOI: 10.1194/jlr.m035154] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Acyl CoA:diacylglycerol acyltransferase-1 (DGAT-1) catalyzes the final step in triacylglycerol (TAG) synthesis and is highly expressed in the small intestine. Because DGAT-1 knockout mice are resistant to diet-induced obesity, we investigated the acute effects of intragastric (IG) infusion of a small molecule diacylglycerol acyltransferase-1 inhibitor (DGAT-1i) on eating, circulating fat metabolites, indirect calorimetry, and hepatic and intestinal expression of key fat catabolism enzymes in male rats adapted to an 8 h feeding-16 h deprivation schedule. Also, the DGAT-1i effect on fatty acid oxidation (FAO) was investigated in enterocyte cell culture models. IG DGAT-1i infusions reduced energy intake compared with vehicle in high-fat diet (HFD)-fed rats, but scarcely in chow-fed rats. IG DGAT-1i also blunted the postprandial increase in serum TAG and increased β-hydroxybutyrate levels only in HFD-fed rats, in which it lowered the respiratory quotient and increased intestinal, but not hepatic, protein levels of Complex III of the mitochondrial respiratory chain and of mitochondrial hydroxymethylglutaryl-CoA synthase. Finally, the DGAT-1i enhanced FAO in CaCo2 (EC50 = 0.3494) and HuTu80 (EC50 = 0.00762) cells. Thus, pharmacological DGAT-1 inhibition leads to an increase in intestinal FAO and ketogenesis when dietary fat is available. This may contribute to the observed eating-inhibitory effect.
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Affiliation(s)
- Gudrun Schober
- Physiology and Behavior Laboratory, Institute of Food, Nutrition, and Health, Swiss Federal Institute of Technology, Zurich, Switzerland.
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Cotter DG, Schugar RC, Crawford PA. Ketone body metabolism and cardiovascular disease. Am J Physiol Heart Circ Physiol 2013; 304:H1060-76. [PMID: 23396451 DOI: 10.1152/ajpheart.00646.2012] [Citation(s) in RCA: 294] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Ketone bodies are metabolized through evolutionarily conserved pathways that support bioenergetic homeostasis, particularly in brain, heart, and skeletal muscle when carbohydrates are in short supply. The metabolism of ketone bodies interfaces with the tricarboxylic acid cycle, β-oxidation of fatty acids, de novo lipogenesis, sterol biosynthesis, glucose metabolism, the mitochondrial electron transport chain, hormonal signaling, intracellular signal transduction pathways, and the microbiome. Here we review the mechanisms through which ketone bodies are metabolized and how their signals are transmitted. We focus on the roles this metabolic pathway may play in cardiovascular disease states, the bioenergetic benefits of myocardial ketone body oxidation, and prospective interactions among ketone body metabolism, obesity, metabolic syndrome, and atherosclerosis. Ketone body metabolism is noninvasively quantifiable in humans and is responsive to nutritional interventions. Therefore, further investigation of this pathway in disease models and in humans may ultimately yield tailored diagnostic strategies and therapies for specific pathological states.
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Affiliation(s)
- David G Cotter
- Department of Medicine, Center for Cardiovascular Research, Washington University, Saint Louis, Missouri 63110, USA
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Cherbuy C, Guesnet P, Morel MT, Kohl C, Thomas M, Duée PH, Prip-Buus C. Oleate metabolism in pig enterocytes is characterized by an increased oxidation rate in the presence of a high esterification rate within two days after birth. J Nutr 2012; 142:221-6. [PMID: 22223579 DOI: 10.3945/jn.111.146068] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Oleate (OLE) is the principle fatty acid (FA) in mammalian colostrum, but its role in the energy supply in enterocytes after birth remains unknown. We investigated the metabolic fate of OLE in pig enterocytes at birth (d0) and after 2 d of suckling (d2). Cellular TG and phospholipids (PL) and FA composition were analyzed. Metabolic end-products of [1-¹⁴C]OLE were measured in enterocyte incubations. We characterized intestinal carnitine palmitoyltransferase 1 (CPT1), the key enzyme of mitochondrial FA oxidation. The TG content was 6.6-fold higher in enterocytes from pigs on d 2 than in those obtained on d 0, whereas the PL content did not differ. The level of OLE in TG and PL increased from 15 and 11% of total FA, respectively, in enterocytes from newborn piglets to 30 and 17%, respectively, in those from d2 pigs. The capacity for OLE utilization was 2.8-fold greater in d2 than in d0 pig enterocytes. The oxidation and esterification rates were enhanced in enterocytes from piglets on d 2 compared to those obtained on d 0, by 4- and 2.6-fold, respectively. The predominant OLE fate was the esterification pathway, representing >85% of OLE metabolized in both groups. The limited OLE oxidation observed at d 2 may result from the presence of a highly malonyl-CoA-sensitive CPT1A, because the half maximal inhibitory concentration for malonyl-CoA was 162 ± 25 nmol/L. This study highlighted the high esterification capacity for OLE in the newborn pig intestine, which may preserve this major colostrum FA for delivery to other tissues.
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Characterization of splice variants of the genes encoding human mitochondrial HMG-CoA lyase and HMG-CoA synthase, the main enzymes of the ketogenesis pathway. Mol Biol Rep 2011; 39:4777-85. [PMID: 21952825 DOI: 10.1007/s11033-011-1270-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 09/14/2011] [Indexed: 10/17/2022]
Abstract
The genes HMGCS2 and HMGCL encode the two main enzymes for ketone-body synthesis, mitochondrial HMG-CoA synthase and HMG-CoA lyase. Here, we identify and describe possible splice variants of these genes in human tissues. We detected an alternative transcript of HMGCS2 carrying a deletion of exon 4, and two alternative transcripts of HMGCL with deletions of exons 5 and 6, and exons 5, 6 and 7, respectively. All splice variants maintained the reading frame. However, Western blot studies and overexpression measurements in eukaryotic or prokaryotic cell models did not reveal HL or mHS protein variants. Both genes showed a similar distribution of the inactive variants in different tissues. Surprisingly, the highest percentages were found in tissues where almost no ketone bodies are synthesized: heart, skeletal muscle and brain. Our results suggest that alternative splicing might coordinately block the two main enzymes of ketogenesis in specific human tissues.
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Langhans W, Leitner C, Arnold M. Dietary fat sensing via fatty acid oxidation in enterocytes: possible role in the control of eating. Am J Physiol Regul Integr Comp Physiol 2011; 300:R554-65. [DOI: 10.1152/ajpregu.00610.2010] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Various mechanisms detect the presence of dietary triacylglycerols (TAG) in the digestive tract and link TAG ingestion to the regulation of energy homeostasis. We here propose a novel sensing mechanism with the potential to encode dietary TAG-derived energy by translating enterocyte fatty acid oxidation (FAO) into vagal afferent signals controlling eating. Peripheral FAO has long been implicated in the control of eating ( 141 ). The prevailing view was that mercaptoacetate (MA) and other FAO inhibitors stimulate eating by modulating vagal afferent signaling from the liver. This concept has been challenged because hepatic parenchymal vagal afferent innervation is scarce and because experimentally induced changes in hepatic FAO often fail to affect eating. Nevertheless, intraperitoneally administered MA acts in the abdomen to stimulate eating because this effect was blocked by subdiaphragmatic vagal deafferentation ( 21 ), a surgical technique that eliminates all vagal afferents from the upper gut. These and other data support a role of the small intestine rather than the liver as a FAO sensor that can influence eating. After intrajejunal infusions, MA also stimulated eating in rats through vagal afferent signaling, and after infusion into the superior mesenteric artery, MA increased the activity of celiac vagal afferent fibers originating in the proximal small intestine. Also, pharmacological interference with TAG synthesis targeting the small intestine induced a metabolic profile indicative of increased FAO and inhibited eating in rats on a high-fat diet but not on chow. Finally, cell culture studies indicate that enterocytes oxidize fatty acids, which can be modified pharmacologically. Thus enterocytes may sense dietary TAG-derived fatty acids via FAO and influence eating through changes in intestinal vagal afferent activity. Further studies are necessary to identify the link between enterocyte FAO and vagal afferents and to examine the specificity and potential physiological relevance of such a mechanism.
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Affiliation(s)
- Wolfgang Langhans
- Physiology and Behavior Laboratory, Institute of Food, Nutrition and Health, Swiss Federal Institute of Technology, Zurich, Schwerzenbach, Switzerland
| | - Claudia Leitner
- Physiology and Behavior Laboratory, Institute of Food, Nutrition and Health, Swiss Federal Institute of Technology, Zurich, Schwerzenbach, Switzerland
| | - Myrtha Arnold
- Physiology and Behavior Laboratory, Institute of Food, Nutrition and Health, Swiss Federal Institute of Technology, Zurich, Schwerzenbach, Switzerland
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25
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Zhang D, Yang H, Kong X, Wang K, Mao X, Yan X, Wang Y, Liu S, Zhang X, Li J, Chen L, Wu J, Wei M, Yang J, Guan Y. Proteomics analysis reveals diabetic kidney as a ketogenic organ in type 2 diabetes. Am J Physiol Endocrinol Metab 2011; 300:E287-95. [PMID: 20959534 DOI: 10.1152/ajpendo.00308.2010] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Diabetic nephropathy (DN) is the leading cause of end-stage renal disease. To date, the molecular mechanisms of DN remain largely unclear. The present study aimed to identify and characterize novel proteins involved in the development of DN by a proteomic approach. Proteomic analysis revealed that 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) synthase 2 (HMGCS2), the key enzyme in ketogenesis, was increased fourfold in the kidneys of type 2 diabetic db/db mice. Consistently, the activity of HMGCS2 in kidneys and 24-h urinary excretion of the ketone body β-hydroxybutyrate (β-HB) were significantly increased in db/db mice. Immunohistochemistry, immunofluorescence, and real-time PCR studies further demonstrated that HMGCS2 was highly expressed in renal glomeruli of db/db mice, with weak expression in the kidneys of control mice. Because filtered ketone bodies are mainly reabsorbed in the proximal tubules, we used RPTC cells, a rat proximal tubule cell line, to examine the effect of the increased level of ketone bodies. Treating cultured RPTC cells with 1 mM β-HB significantly induced transforming growth factor-β1 expression, with a marked increase in collagen I expression. β-HB treatment also resulted in a marked increase in vimentin protein expression and a significant reduction in E-cadherin protein levels, suggesting an enhanced epithelial-to-mesenchymal transition in RPTCs. Collectively, these findings demonstrate that diabetic kidneys exhibit excess ketogenic activity resulting from increased HMGCS2 expression. Enhanced ketone body production in the diabetic kidney may represent a novel mechanism involved in the pathogenesis of DN.
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Affiliation(s)
- Dongjuan Zhang
- Dept. of Physiology and Pathophysiology, Peking University Health Science Ctr., Haidian District, Beijing, China
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26
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Sun Y, Lee SMY, Wong YM, Lau CP, Shaw PC, Qin L, Leung PC, Fung KP. Dosing effects of an antiosteoporosis herbal formula--a preclinical investigation using a rat model. Phytother Res 2008; 22:267-73. [PMID: 17726734 DOI: 10.1002/ptr.2291] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Herba Epimedii, Fructus Ligustri Lucidi and Fructus Psoraleae are three frequently used Chinese herbs traditionally used for tonifying the 'kidney system'. They were selected for the present study to formulate an herbal preparation with a weight ratio of 5:4:1 based on their phytochemical, nature, documented treatment efficacy and toxicity. The dosing effects (1 g/day, 0.5 g/day and 0.175 g/day) of the antiosteoporosis function of the water extract of this formula were tested in ovariectomy- and calcium deficiency-induced osteoporotic rats. Eleven weeks of herbal treatment demonstrated a beneficial effect on the preservation of bone mineral density (BMD) at the femur neck in a dose-dependent manner with the preference for higher dosage. No significant increase in uterus weight was observed in the herbal formula treated rats. In addition, microarray data of kidney tissue revealed that this herbal formula was able to down-regulate the expression of phase II drug metabolizing enzymes, similar to the effects of estrogens.
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Affiliation(s)
- Ye Sun
- Institute of Chinese Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
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27
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Ogura Y, Mochizuki K, Goda T. Induction of histone acetylation on the CRBPII gene in perinatal rat small intestine. Biochim Biophys Acta Gen Subj 2007; 1770:1289-96. [PMID: 17692466 DOI: 10.1016/j.bbagen.2007.06.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2007] [Revised: 06/03/2007] [Accepted: 06/26/2007] [Indexed: 10/23/2022]
Abstract
The expression of genes associated with lipid and vitamin A metabolism is elevated when the small intestinal mucosa is maturing rapidly during the perinatal period. We have previously reported that cellular retinol-binding protein type II (CRBPII) mRNA levels rise abruptly in the rat small intestine during this period. In this study, we examined whether the acetylation of histones H3 and H4 is involved in the intestinal expression of CRBPII during the perinatal stage. The expression of cyclin D1 and cyclin B1 genes, which are markers of cell proliferation, decreased markedly during the perinatal period, whereas expression of CRBPII as well as villin, a marker of intestinal maturation, increased rapidly. Using a ChIP assay, we showed rapid induction of acetylation of the histones H3 and H4 which interacted with the promoter/enhancer region of the CRBPII gene at this time. The binding of CBP and p300, which have histone acetyltransferase activity, as well as binding of retinoid X receptor alpha (RXRalpha) increased on the CRBPII promoter/enhancer region during the perinatal period. These results suggest that CRBPII gene expression during the perinatal period is associated with abrupt acetylation of histones H3 and H4 followed by the binding of CBP/p300 and RXRalpha.
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Affiliation(s)
- Yuko Ogura
- Laboratory of Nutritional Physiology and COE Program in the 21st Century, University of Shizuoka School of Food and Nutritional Sciences, 52-1 Yada, Shizuoka 422-8526, Japan
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28
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Badman MK, Pissios P, Kennedy AR, Koukos G, Flier JS, Maratos-Flier E. Hepatic fibroblast growth factor 21 is regulated by PPARalpha and is a key mediator of hepatic lipid metabolism in ketotic states. Cell Metab 2007; 5:426-37. [PMID: 17550778 DOI: 10.1016/j.cmet.2007.05.002] [Citation(s) in RCA: 1193] [Impact Index Per Article: 70.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2007] [Revised: 04/06/2007] [Accepted: 05/03/2007] [Indexed: 02/06/2023]
Abstract
Mice fed a high-fat, low-carbohydrate ketogenic diet (KD) exhibit marked changes in hepatic metabolism and energy homeostasis. Here, we identify liver-derived fibroblast growth factor 21 (FGF21) as an endocrine regulator of the ketotic state. Hepatic expression and circulating levels of FGF21 are induced by both KD and fasting, are rapidly suppressed by refeeding, and are in large part downstream of PPARalpha. Importantly, adenoviral knockdown of hepatic FGF21 in KD-fed mice causes fatty liver, lipemia, and reduced serum ketones, due at least in part to altered expression of key genes governing lipid and ketone metabolism. Hence, induction of FGF21 in liver is required for the normal activation of hepatic lipid oxidation, triglyceride clearance, and ketogenesis induced by KD. These findings identify hepatic FGF21 as a critical regulator of lipid homeostasis and identify a physiological role for this hepatic hormone.
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Affiliation(s)
- Michael K Badman
- Division of Endocrinology, Department of Medicine, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215, USA
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29
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Camarero N, Mascaró C, Mayordomo C, Vilardell F, Haro D, Marrero PF. KetogenicHMGCS2Is a c-Myc Target Gene Expressed in Differentiated Cells of Human Colonic Epithelium and Down-Regulated in Colon Cancer. Mol Cancer Res 2006; 4:645-53. [PMID: 16940161 DOI: 10.1158/1541-7786.mcr-05-0267] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
HMGCS2, the gene that regulates ketone body production, is expressed in liver and several extrahepatic tissues, such as the colon. In CaCo-2 colonic epithelial cells, the expression of this gene increases with cell differentiation. Accordingly, immunohistochemistry with specific antibodies shows that HMGCS2 is expressed mainly in differentiated cells of human colonic epithelium. Here, we used a chromatin immunoprecipitation assay to study the molecular mechanism responsible for this expression pattern. The assay revealed that HMGCS2 is a direct target of c-Myc, which represses HMGCS2 transcriptional activity. c-Myc transrepression is mediated by blockade of the transactivating activity of Miz-1, which occurs mainly through a Sp1-binding site in the proximal promoter of the gene. Accordingly, the expression of human HMGCS2 is down-regulated in 90% of Myc-dependent colon and rectum tumors. HMGCS2 protein expression is down-regulated preferentially in moderately and poorly differentiated carcinomas. In addition, it is also down-regulated in 80% of small intestine Myc-independent tumors. Based on these findings, we propose that ketogenesis is an undesirable metabolic characteristic of the proliferating cell, which is down-regulated through c-Myc-mediated repression of the key metabolic gene HMGCS2.
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Affiliation(s)
- Nuria Camarero
- Department of Biochemistry and Molecular Biology, School of Pharmacy, University of Barcelona, E-08028 Barcelona, Spain
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30
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Ogura Y, Suruga K, Takase S, Goda T. Developmental changes of the expression of the genes regulated by retinoic acid in the small intestine of rats. Life Sci 2006; 77:2804-13. [PMID: 15964596 DOI: 10.1016/j.lfs.2005.05.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2004] [Accepted: 05/03/2005] [Indexed: 11/28/2022]
Abstract
Retinoic acid (RA) serves as a hormone-like nutrient and it plays pivotal roles in cellular differentiation and proliferation in various tissues including the small intestine. In this study, we aimed to explore a possible role of RA signaling in the developing rat small intestine of perinatal (embryonic and newborn) and suckling-weaning transition period, and we investigated the changes in the expression of several genes regulated by RA. Northern blot analysis showed that both retinal dehydrogenase 1 (RALDH1) and retinal dehydrogenase 2 (RALDH2) mRNA levels were higher in 19-day fetal (2 days before birth) small intestine and then declined after birth. Retinoid X receptor alpha (RXRalpha) mRNA and retinoic acid receptor alpha (RARalpha) mRNA levels in the small intestine showed high levels in perinatal period compared with suckling-weaning transition period. RA-target genes such as retinoic acid receptor beta (RARbeta) and cellular retinol-binding protein, type II (CRBPII) mRNA levels were significantly increased in the perinatal small intestine. Furthermore, mRNA levels of hepatocyte nuclear factor-4 (HNF-4), which is one of the possible RA-target gene and a transcription factor regulating CRBPII gene expression, was also increased in the perinatal small intestine. These results suggest that the possible perinatal RA production by RALDHs might regulate various RA-target genes including CRBPII and RARalpha through RXRalpha or HNF-4 in the small intestine.
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Affiliation(s)
- Yuko Ogura
- Laboratory of Nutritional Physiology and COE Program in the 21st Century, University of Shizuoka School of Food and Nutritional Sciences, 52-1 Yada, Shizuoka-shi 422-8526, Japan
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31
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Sirinupong N, Suwanmanee P, Doolittle RF, Suvachitanont W. Molecular cloning of a new cDNA and expression of 3-hydroxy-3-methylglutaryl-CoA synthase gene from Hevea brasiliensis. PLANTA 2005; 221:502-12. [PMID: 15744497 DOI: 10.1007/s00425-004-1463-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2004] [Accepted: 11/15/2004] [Indexed: 05/09/2023]
Abstract
3-Hydroxy-3-methylglutaryl-CoA synthase (HMGS), EC 4.1.3.5, is an essential enzyme in rubber biosynthesis in Hevea brasiliensis. We have isolated a new cDNA encoding HMGS in H. brasiliensis. The full-length hmgs2 consists of 1,916-bp and encodes a protein of 464 amino acids with a predicted molecular mass of 51.27 kDa and an isoelectric point of 6.02. In comparison, HMGS1 and HMGS2 show 92% and 94% nucleotide and amino acid sequence identities, respectively. Semiquantitative RT-PCR analysis indicates that the hmgs2 is more highly expressed in laticifer and petiole than in leaves. Sequence searching and alignment revealed that HMGS is a distant relative of the condensing enzyme; beta-ketoacyl acyl carrier protein synthase III (ACP synthase III), EC 2.3.1.41, identified three completely conserved residues; Cys(117), His(247), and Asn(326). The relationship was greatly strengthened by making a proper alignment of numerous sequences of both HMGS and ACP synthase III. The same Cys(117), His(247), and Asn(326) absolutely conserved in both groups play a catalytic role in ACP synthase III, while such a role of Cys and His has only been reported for HMGS. According to site-directed mutagenesis, the expressed wild-type enzyme shows comparable level with mutant proteins. The mutation of Cys(117) and Asn(326) affects the HMGS activity, indicating that Cys(117) and Asn(326) are important amino acids for the catalytic activity of HMGS. A phylogenetic tree constructed on the basis of proper multiple alignment indicates that HMGS1 and HMGS2 result from recent gene duplication. This is also the case for HMGS and ACP synthase III, which appear to have arisen from an ancient gene duplication event of an ancestral condensing enzyme. Therefore, a possible secondary structure of HMGS could be predicted based on the Protein Data Bank information of ACP synthase III.
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Affiliation(s)
- Nualpun Sirinupong
- Biochemistry Department, Faculty of Science, Prince of Songkla University, Hat Yai, 90112, Thailand
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32
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Lavrentyev EN, He D, Cook GA. Expression of genes participating in regulation of fatty acid and glucose utilization and energy metabolism in developing rat hearts. Am J Physiol Heart Circ Physiol 2004; 287:H2035-42. [PMID: 15217797 DOI: 10.1152/ajpheart.00372.2004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The heart is a unique organ that can use several fuels for energy production. During development, the heart undergoes changes in fuel supply, and it must be able to respond to these changes. We have examined changes in the expression of several genes that regulate fuel transport and metabolism in rat hearts during early development. At birth, there was increased expression of fatty acid transporters and enzymes of fatty acid metabolism that allow fatty acids to become the major source of energy for cardiac muscle during the first 2 wk of life. At the same time, expression of genes that control glucose transport and oxidation was downregulated. After 2 wk, expression of genes for glucose uptake and oxidation was increased, and expression of genes for fatty acid uptake and utilization was decreased. Expression of carnitine palmitoyltransferase I (CPT I) isoforms during development was different from published data obtained from rabbit hearts. CPT Iα and Iβ isoforms were both highly expressed in hearts before birth, and both increased further at birth. Only after the second week did CPT Iα expression decrease appreciably below the level of CPT Iβ expression. These results represent another example of different expression patterns of CPT I isoforms among various mammalian species. In rats, changes in gene expression followed nutrient availability during development and may render cardiac fatty acid oxidation less sensitive to factors that influence malonyl-CoA content (e.g., fluctuations in glucose concentration) and thereby favor fatty acid oxidation as an energy source for cardiomyocytes in early development.
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Affiliation(s)
- Eduard N Lavrentyev
- Dept. of Pharmacology, College of Medicine, Univ. of Tennessee Health Science Center, 874 Union Ave., Memphis, TN 38163, USA
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Fukao T, Lopaschuk GD, Mitchell GA. Pathways and control of ketone body metabolism: on the fringe of lipid biochemistry. Prostaglandins Leukot Essent Fatty Acids 2004; 70:243-51. [PMID: 14769483 DOI: 10.1016/j.plefa.2003.11.001] [Citation(s) in RCA: 264] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Ketone bodies become major body fuels during fasting and consumption of a high-fat, low-carbohydrate (ketogenic) diet. Hyperketonemia is associated with potential health benefits. Ketone body synthesis (ketogenesis) is the last recognizable step of lipid energy metabolism, a pathway that links dietary lipids and adipose triglycerides to the Krebs cycle and respiratory chain and has three highly regulated control points: (1) adipocyte lipolysis, (2) mitochondrial fatty acids entry, controlled by the inhibition of carnitine palmityl transferase I by malonyl coenzyme A (CoA) and (3) mitochondrial 3-hydroxy-3-methylglutaryl CoA synthase, which catalyzes the irreversible first step of ketone body synthesis. Each step is suppressed by an elevated circulating insulin level or insulin/glucagon ratio. The utilization of ketone bodies (ketolysis) also determines circulating ketone body levels. Consideration of ketone body metabolism reveals the mechanisms underlying the extreme fragility of dietary ketosis to carbohydrate intake and highlights areas for further study.
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Affiliation(s)
- Toshiyuki Fukao
- Department of Pediatrics, Gifu University School of Medicine, Gifu 500, Japan
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Camarero N, Nadal A, Barrero MJ, Haro D, Marrero PF. Histone deacetylase inhibitors stimulate mitochondrial HMG-CoA synthase gene expression via a promoter proximal Sp1 site. Nucleic Acids Res 2003; 31:1693-703. [PMID: 12626711 PMCID: PMC152864 DOI: 10.1093/nar/gkg262] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The expression of mitochondrial HMG-CoA synthase in the colon has been correlated with the levels of butyrate present in this tissue. We report here that the effect of butyrate on mitochondrial HMG-CoA synthase gene expression is exerted in vivo at the transcriptional level, and that trichostatin A (TSA), a specific histone deacetylase inhibitor, also induces transcriptional activity and mRNA expression of the gene in human cell lines derived from colon carcinoma. Using chromatin immunoprecipitation assays, we show that histone deacetylase 1 (HDAC1) is associated with the endogenous mitochondrial HMG-CoA synthase promoter and that TSA induction correlates with hyperacetylation of H4 histone associated with the 5' flanking region of the gene. Overexpression of HDAC1 activity leads consistently to mitochondrial HMG-CoA synthase promoter hypoacetylation and reduces its transcriptional activity. The effect of butyrate and TSA maps to a single Sp1 site present in the proximal promoter of the gene, which is able to bind Sp1 and Sp3 proteins. Interestingly, the binding affinity of Sp1 and Sp3 proteins to the Sp1 site correlates with the TSA responsiveness of the promoter. Using a one-hybrid system (GAL4-Sp1 and GAL4-Sp3), we show that both proteins can mediate responsiveness to TSA in CaCo-2 cells employing distinct mechanisms.
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Affiliation(s)
- Nuria Camarero
- Department of Biochemistry and Molecular Biology, School of Pharmacy, University of Barcelona, Av. Diagonal 643, 08028 Barcelona, Spain
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Nadal A, Marrero PF, Haro D. Down-regulation of the mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase gene by insulin: the role of the forkhead transcription factor FKHRL1. Biochem J 2002; 366:289-97. [PMID: 12027802 PMCID: PMC1222772 DOI: 10.1042/bj20020598] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2002] [Revised: 05/23/2002] [Accepted: 05/23/2002] [Indexed: 01/07/2023]
Abstract
Normal physiological responses to carbohydrate shortages cause the liver to increase the production of ketone bodies from the acetyl-CoA generated from fatty acid oxidation. This allows the use of ketone bodies for energy, thereby preserving the limited glucose for use by the brain. This adaptative response is switched off by insulin rapidly inhibiting the expression of the mitochondrial 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) synthase (HMGCS2) gene, which is a key control site of ketogenesis. We decided to investigate the molecular mechanism of this inhibition. In the present study, we show that FKHRL1, a member of the forkhead in rhabdosarcoma (FKHR) subclass of the Fox family of transcription factors, stimulates transcription from transfected 3-hydroxy-3-methylglutaryl-CoA synthase promoter-luciferase reporter constructs, and that this stimulation is repressed by insulin. An FKHRL1-responsive sequence AAAAATA, located 211 bp upstream of the HMGCS2 gene transcription start site, was identified by deletion analysis. It binds FKHRL1 in vivo and in vitro and confers FKHRL1 responsiveness on homologous and heterologous promoters. If it is mutated, it partially blocks the effect of insulin in HepG2 cells, both in the absence and presence of overexpressed FKHRL1. These results suggest that FKHRL1 contributes to the regulation of HMGCS2 gene expression by insulin.
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Affiliation(s)
- Alícia Nadal
- Department of Biochemistry and Molecular Biology, School of Pharmacy, University of Barcelona, Avda. Diagonal, 643, E-08028 Barcelona, Spain
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36
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Abstract
The control of mitochondrial beta-oxidation, including the delivery of acyl moieties from the plasma membrane to the mitochondrion, is reviewed. Control of beta-oxidation flux appears to be largely at the level of entry of acyl groups to mitochondria, but is also dependent on substrate supply. CPTI has much of the control of hepatic beta-oxidation flux, and probably exerts high control in intact muscle because of the high concentration of malonyl-CoA in vivo. beta-Oxidation flux can also be controlled by the redox state of NAD/NADH and ETF/ETFH(2). Control by [acetyl-CoA]/[CoASH] may also be significant, but it is probably via export of acyl groups by carnitine acylcarnitine translocase and CPT II rather than via accumulation of 3-ketoacyl-CoA esters. The sharing of control between CPTI and other enzymes allows for flexible regulation of metabolism and the ability to rapidly adapt beta-oxidation flux to differing requirements in different tissues.
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Affiliation(s)
- Simon Eaton
- Surgery Unit, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK.
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Abstract
Targeted gene mutations have established distinct, yet overlapping, developmental roles for receptors of the insulin/IGF family. IGF-I receptor mediates IGF-I and IGF-II action on prenatal growth and IGF-I action on postnatal growth. Insulin receptor mediates prenatal growth in response to IGF-II and postnatal metabolism in response to insulin. In rodents, unlike humans, insulin does not participate in embryonic growth until late gestation. The ability of the insulin receptor to act as a bona fide IGF-II-dependent growth promoter is underscored by its rescue of double knockout Igf1r/Igf2r mice. Thus, IGF-II is a true bifunctional ligand that is able to stimulate both insulin and IGF-I receptor signaling, although with different potencies. In contrast, the IGF-II/cation-independent mannose-6-phosphate receptor regulates IGF-II clearance. The growth retardation of mice lacking IGF-I and/or insulin receptors is due to reduced cell number, resulting from decreased proliferation. Evidence from genetically engineered mice does not support the view that insulin and IGF receptors promote cellular differentiation in vivo or that they are required for early embryonic development. The phenotypes of insulin receptor gene mutations in humans and in mice indicate important differences between the developmental roles of insulin and its receptor in the two species.
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Affiliation(s)
- J Nakae
- Naomi Berrie Diabetes Center, Department of Medicine, College of Physicians & Surgeons of Columbia University, New York, New York 10032, USA
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Louet JF, Chatelain F, Decaux JF, Park EA, Kohl C, Pineau T, Girard J, Pegorier JP. Long-chain fatty acids regulate liver carnitine palmitoyltransferase I gene (L-CPT I) expression through a peroxisome-proliferator-activated receptor alpha (PPARalpha)-independent pathway. Biochem J 2001; 354:189-97. [PMID: 11171094 PMCID: PMC1221643 DOI: 10.1042/0264-6021:3540189] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Liver carnitine palmitoyltransferase I (L-CPT I) catalyses the transfer of long-chain fatty acid (LCFA) for translocation across the mitochondrial membrane. Expression of the L-CPT I gene is induced by LCFAs as well as by lipid-lowering compounds such as clofibrate. Previous studies have suggested that the peroxisome-proliferator-activated receptor alpha (PPARalpha) is a common mediator of the transcriptional effects of LCFA and clofibrate. We found that free LCFAs rather than acyl-CoA esters are the signal metabolites responsible for the stimulation of L-CPT I gene expression. Using primary culture of hepatocytes we found that LCFAs failed to stimulate L-CPT I gene expression both in wild-type and PPARalpha-null mice. These results suggest that the PPARalpha-knockout mouse does not represent a suitable model for the regulation of L-CPT I gene expression by LCFAs in the liver. Finally, we determined that clofibrate stimulates L-CPT I through a classical direct repeat 1 (DR1) motif in the promoter of the L-CPT I gene while LCFAs induce L-CPT I via elements in the first intron of the gene. Our results demonstrate that LCFAs can regulate gene expression through PPARalpha-independent pathways and suggest that the regulation of gene expression by dietary lipids is more complex than previously proposed.
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MESH Headings
- Animals
- Base Sequence
- Carnitine O-Palmitoyltransferase/genetics
- Cells, Cultured
- Clofibrate/pharmacology
- DNA Primers
- Enzyme Inhibitors/pharmacology
- Fatty Acids/physiology
- Female
- Gene Expression Regulation, Enzymologic/physiology
- Hepatocytes/drug effects
- Hepatocytes/metabolism
- Liver/enzymology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Promoter Regions, Genetic
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats
- Rats, Wistar
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/physiology
- Transcription Factors/genetics
- Transcription Factors/physiology
- Tumor Cells, Cultured
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Affiliation(s)
- J F Louet
- Endocrinologie Métabolisme et Développement, CNRS UPR 1524, 9, rue Jules Hetzel, 92190 Meudon, France
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39
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Barrero MJ, Alho CS, Ortiz JA, Hegardt FG, Haro D, Marrero PF. Low Activity of Mitochondrial HMG-CoA Synthase in Liver of Starved Piglets Is Due to Low Levels of Protein Despite High mRNA Levels. Arch Biochem Biophys 2001; 385:364-71. [PMID: 11368018 DOI: 10.1006/abbi.2000.2146] [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: 11/22/2022]
Abstract
The unusually low hepatic ketogenic capacity of piglets has been correlated with lack of expression of the mitochondrial HMG-CoA synthase gene. However, we have shown that starvation of 2-week-old piglets increased the mRNA levels of mitochondrial HMG-CoA synthase to a level similar to that observed in starved rats (S. H. Adams, C. S. Alho, G. Asins, F. G. Hegardt, and P. F. Marrero, 1997, Biochem. J. 324, 65-73). We now report that antibodies against pig mitochondrial HMG-CoA synthase detected the pig enzyme in mitochondria of 2-week-old starved piglets and that the pig mitochondrial HMG-CoA synthase cDNA encodes an active enzyme in the eukaryotic cell line Mev-1, with catalytic behavior similar to that of the rat enzyme when expressed in the same system. We also show that low activity of pig mitochondrial HMG-CoA synthase correlates with low expression of the pig enzyme. The discrepancy in mitochondrial HMG-CoA synthase gene expression between the high levels of mRNA and low levels of enzyme was not associated with differences in transcript maturation, which suggests that an attenuated translation of the pig mRNA is responsible for the diminished ketogenic capacity of pig mitochondria.
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Affiliation(s)
- M J Barrero
- Department of Biochemistry and Molecular Biology, School of Pharmacy, University of Barcelona, Spain
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40
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Abstract
During late gestation, although maternal adipose tissue lipolytic activity becomes enhanced, lipolytic products cross the placenta with difficulty. Under fasting conditions, free fatty acids (FFA) are used for ketogenesis by the mother, and ketone bodies are used as fuels and lipogenic substrates by the fetus. Maternal glycerol is preferentially used for glucose synthesis, saving other gluconeogenic substrates, like amino acids, for fetal growth. Placental transfer of triglycerides is null, but essential fatty acids derived from maternal diet, which are transported as triglycerides in lipoproteins, become available to the fetus owing to the presence of both lipoprotein receptors and lipase activities in the placenta. Diabetes in pregnancy promotes lipid transfer to the fetus by increasing the maternal-fetal gradient, which may contribute to an increase in body fat mass in newborns of diabetic women. Deposition of fat stores in the fetus is very low in the rat but high in humans, where body fat accretion occurs essentially during the last trimester of intra-uterine life. This is sustained by the intense placental transfer of glucose and by its use as a lipogenic substrate, as well as by the placental transfer of fatty acids and to their low oxidation activity. During the perinatal period an active ketonemia develops, which is maintained in the suckling newborn by several factors: (i) the high-fat and low-carbohydrate content in milk, (ii) the enhanced lipolytic activity occurring during the first few hours of life, and (iii) both the uptake of circulating triglycerides by the liver due to the induction of lipoprotein lipase (LPL) activity in this organ, and the presence of ketogenic activity in the intestinal mucose. Changes in LPL activity, lipogenesis and lipolysis contribute to the sequential steps of adipocyte hyperplasia and hypertrophia occurring during the extra-uterine white adipose tissue development in rat, and this may be used as a model to extrapolate the intra-uterine adipose tissue development in other species, including humans.
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Affiliation(s)
- E Herrera
- Facultad de Ciencias Experimentales y Técnicas, Universidad San Pablo-CEU, E-28668 Madrid, Spain.
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41
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Cullingford TE, Bhakoo KK, Peuchen S, Dolphin CT, Clark JB. Regulation of the ketogenic enzyme mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase in astrocytes and meningeal fibroblasts. Implications in normal brain development and seizure neuropathologies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2000; 466:241-51. [PMID: 10709651 DOI: 10.1007/0-306-46818-2_29] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Affiliation(s)
- T E Cullingford
- Department of Neurochemistry, Institute of Neurology, London, U.K
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42
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New KJ, Eaton S, Elliott KR, Quant PA. Is it time to reconsider the role of CPT I in control of hepatic ketogenesis? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2000; 466:227-32. [PMID: 10709649 DOI: 10.1007/0-306-46818-2_27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Affiliation(s)
- K J New
- Unit of Paediatric Surgery, Institute of Child Health, NHS Trust University College, London Medical School, U.K
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43
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Thumelin S, Kohl C, Girard J, Pégorier JP. Atypical expression of mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase in subcutaneous adipose tissue of male rats. J Lipid Res 1999. [DOI: 10.1016/s0022-2275(20)33511-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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44
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Hegardt FG. Mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase: a control enzyme in ketogenesis. Biochem J 1999; 338 ( Pt 3):569-82. [PMID: 10051425 PMCID: PMC1220089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Cytosolic and mitochondrial 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) synthases were first recognized as different chemical entities in 1975, when they were purified and characterized by Lane's group. Since then, the two enzymes have been studied extensively, one as a control site of the cholesterol biosynthetic pathway and the other as an important control site of ketogenesis. This review describes some key developments over the last 25 years that have led to our current understanding of the physiology of mitochondrial HMG-CoA synthase in the HMG-CoA pathway and in ketogenesis in the liver and small intestine of suckling animals. The enzyme is regulated by two systems: succinylation and desuccinylation in the short term, and transcriptional regulation in the long term. Both control mechanisms are influenced by nutritional and hormonal factors, which explains the incidence of ketogenesis in diabetes and starvation, during intense lipolysis, and in the foetal-neonatal and suckling-weaning transitions. The DNA-binding properties of the peroxisome-proliferator-activated receptor and other transcription factors on the nuclear-receptor-responsive element of the mitochondrial HMG-CoA synthase promoter have revealed how ketogenesis can be regulated by fatty acids. Finally, the expression of mitochondrial HMG-CoA synthase in the gonads and the correction of auxotrophy for mevalonate in cells deficient in cytosolic HMG-CoA synthase suggest that the mitochondrial enzyme may play a role in cholesterogenesis in gonadal and other tissues.
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Affiliation(s)
- F G Hegardt
- Department of Biochemistry and Molecular Biology, School of Pharmacy, University of Barcelona, Av/ Diagonal 643, 08028 Barcelona, Spain.
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45
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Ortiz JA, Mallolas J, Nicot C, Bofarull J, Rodríguez JC, Hegardt FG, Haro D, Marrero PF. Isolation of pig mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase gene promoter: characterization of a peroxisome proliferator-responsive element. Biochem J 1999; 337 ( Pt 2):329-35. [PMID: 9882632 PMCID: PMC1219969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Low expression of the mitochondrial 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) synthase gene during development correlates with an unusually low hepatic ketogenic capacity and lack of hyperketonaemia in piglets. Here we report the isolation and characterization of the 5' end of the pig mitochondrial HMG-CoA synthase gene. The 581 bp region proximal to the transcription start site permits transcription of a reporter gene, confirming the function of the promoter. The pig mitochondrial HMG-CoA synthase promoter is trans-activated by the peroxisomal proliferator-activated receptor (PPAR), and a functional response element for PPAR (PPRE) has been localized in the promoter region. Pig PPRE is constituted by an imperfect direct repeat (DR-1) and a downstream sequence, both of which are needed to confer PPAR-sensitivity to a thymidine kinase promoter and to form complexes with PPAR.retinoid X receptor heterodimers. A role of PPAR trans-activation in starvation-associated induction of gene expression is suggested.
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Affiliation(s)
- J A Ortiz
- Departamento de Bioqu approximately ímica y Biolog approximately ía Molecular, Facultad de Farmacia, Universidad de Barcelona, Avda. Diagonal 643, 08028 Barcelona, Spain
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46
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Lionetti L, Iossa S, Liverini G, Brand MD. Changes in the hepatic mitochondrial respiratory system in the transition from weaning to adulthood in rats. Arch Biochem Biophys 1998; 352:240-6. [PMID: 9587412 DOI: 10.1006/abbi.1998.0579] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the present study we investigated the changes in the hepatic mitochondrial respiratory system in the transition from weaning to adulthood in the rat. We conceptually divided the system into blocks of reactions that produced or consumed mitochondrial membrane potential and then measured the kinetic responses of these blocks of reactions to changes in this potential in isolated liver mitochondria from 25- and 60-day-old rats using succinate as substrate. Moreover, we considered the mitochondrial membrane potential producers to be divided into blocks of reactions that reduced or oxidized ubiquinone-2 (Q-2) and then measured the kinetic responses of these two blocks to changes in Q-2 redox state as well as the flux control coefficients and the cytochrome content. We found that adult rats exhibited significantly higher state 3 respiratory rates with increased kinetic response of the substrate oxidation pathway to the mitochondrial membrane potential, slightly decreased activity of the phosphorylating system, increased kinetic responses of both Q-2 reducers and oxidizers to Q-2 redox state, and increased cytochrome content. Our results indicate that important changes in the hepatic mitochondrial respiratory system occur in the transition from weaning to adulthood in rats.
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Affiliation(s)
- L Lionetti
- Department of General and Environmental Physiology, University of Naples, Italy
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47
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Cullingford TE, Dolphin CT, Bhakoo KK, Peuchen S, Canevari L, Clark JB. Molecular cloning of rat mitochondrial 3-hydroxy-3-methylglutaryl-CoA lyase and detection of the corresponding mRNA and of those encoding the remaining enzymes comprising the ketogenic 3-hydroxy-3-methylglutaryl-CoA cycle in central nervous system of suckling rat. Biochem J 1998; 329 ( Pt 2):373-81. [PMID: 9425122 PMCID: PMC1219054 DOI: 10.1042/bj3290373] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We have investigated, by RNase protection assays in rat brain regions and primary cortical astrocyte cultures, the presence of the mRNA species encoding the three mitochondrially located enzymes acetoacetyl-CoA thiolase, mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase (mt. HMG-CoA synthase) and HMG-CoA lyase (HMG-CoA lyase) that together constitute the ketogenic HMG-CoA cycle. As a prerequisite we obtained a full-length cDNA encoding rat HMG-CoA lyase by degenerate oligonucleotide-primed PCR coupled to a modification of PCR-rapid amplification of cDNA ends (PCR-RACE). We report here: (1) the nucleotide sequence of rat mt. HMG-CoA lyase, (2) detection of the mRNA species encoding all three HMG-CoA cycle enzymes in all regions of rat brain during suckling, (3) approximately twice the abundance of mt. HMG-CoA synthase mRNA in cerebellum than in cortex in 11-day-old suckling rat pups, (4) significantly lower abundances of mt. HMG-CoA synthase mRNA in brain regions derived from rats weaned to a high-carbohydrate/low-fat diet compared with the corresponding regions derived from the suckling rat, and (5) the presence of mt. HMG-CoA synthase mRNA in primary cultures of neonatal cortical astrocytes at an abundance similar to that found in liver of weaned animals. These results provide preliminary evidence that certain neural cell types possess ketogenic potential and might thus have a direct role in the provision of fatty acid-derived ketone bodies during the suckling period.
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Affiliation(s)
- T E Cullingford
- Department of Neurochemistry, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, U.K
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48
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Arias G, Asins G, Hegardt FG, Serra D. The effect of dexamethasone treatment on the expression of the regulatory genes of ketogenesis in intestine and liver of suckling rats. Mol Cell Biochem 1998; 178:325-33. [PMID: 9546617 DOI: 10.1023/a:1006875716407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The influence of the injection of dexamethasone on ketogenesis in 12 day old suckling rats was studied in intestine and liver by determining mRNA levels and enzyme activity of the two genes responsible for regulation of ketogenesis: carnitine palmitoyl transferase I (CPT I) and mitochondrial HMG-CoA synthase. Dexamethasone produced a 2 fold increase in mRNA and activity of CPT I in intestine, but led to a decrease in mit. HMG-CoA synthase. In liver the mRNA levels and activity of both CPT I and mit. HMG-CoA synthase decreased. Comparison of these values with the ketogenic rate of both tissues following dexamethasone treatment suggests that mit. HMG-CoA synthase could be the main gene responsible for the regulation of ketogenesis in suckling rats. The changes produced in serum ketone bodies by dexamethasone, with a profile that is more similar to the ketogenic rate in the liver than that in the intestine, indicate that liver contributes more to ketone body synthesis in suckling rats. Two day treatment with dexamethasone produced no change in mRNA or activity levels for CPT I in liver or intestine. While mRNA levels for mit. HMG-CoA synthase changed little, the enzyme activity is decreased in both tissues.
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Affiliation(s)
- G Arias
- Department of Biochemistry, School of Pharmacy, University of Barcelona, Spain
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49
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Boukaftane Y, Mitchell GA. Cloning and characterization of the human mitochondrial 3-hydroxy-3-methylglutaryl CoA synthase gene. Gene 1997; 195:121-6. [PMID: 9305755 DOI: 10.1016/s0378-1119(97)00067-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We report the characterization of lambda and P1 phage clones containing the entire human mitochondrial 3-hydroxy-3-methylglutaryl CoA synthase (mHS) gene. The human mHS locus (HMGCS2) on chromosome 1p12-13 spans 25 kb and contains 10 exons. Exon 1 contains most of the mitochondrial leader, consistent with a recent hypothesis of the evolution of the ketogenic pathway. By primer extension and cDNA amplification (RACE-PCR) we localized the transcription start point (tsp) to 60 bp upstream of the initiation codon. Nine blocks of conserved sequence were identified by comparing the 5' flanking regions of the mHS genes of human and rat. The 5' flanking region contains potential binding sites for TATA-binding protein, Sp1, nuclear factor 1 (NF1), CAAT-box binding protein (C/EBP), hepatocyte nuclear factors 1 and 5 (HNF1, HNF5) and activator proteins 1 and 2 (AP1, AP2).
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Affiliation(s)
- Y Boukaftane
- Service de génétique médicale, Hôpital Ste-Justine, Université de Montréal, Québec, Canada
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50
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Adams SH, Alho CS, Asins G, Hegardt FG, Marrero PF. Gene expression of mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase in a poorly ketogenic mammal: effect of starvation during the neonatal period of the piglet. Biochem J 1997; 324 ( Pt 1):65-73. [PMID: 9164842 PMCID: PMC1218402 DOI: 10.1042/bj3240065] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The low ketogenic capacity of pigs correlates with a low activity of mitochondrial 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) synthase. To identify the molecular mechanism controlling such activity, we isolated the pig cDNA encoding this enzyme and analysed changes in mRNA levels and mitochondrial specific activity induced during development and starvation. Pig mitochondrial synthase showed a tissue-specific expression pattern. As with rat and human, the gene is expressed in liver and large intestine; however, the pig differs in that mRNA was not detected in testis, kidney or small intestine. During development, pig mitochondrial HMG-CoA synthase gene expression showed interesting differences from that in the rat: (1) there was a 2-3 week lag in the postnatal induction; (2) the mRNA levels remained relatively abundant through the suckling-weaning transition and at maturity, in contrast with the fall observed in rats at similar stages of development; and (3) the gene expression was highly induced by fasting during the suckling, whereas no such change in mitochondrial HMG-CoA synthase mRNA levels has been observed in rat. The enzyme activity of mitochondrial HMG-CoA synthase increased 27-fold during starvation in piglets, but remained one order of magnitude lower than rats. These results indicate that post-transcriptional mechanism(s) and/or intrinsic differences in the encoded enzyme are responsible for the low activity of pig HMG-CoA synthase observed throughout development or after fasting.
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Affiliation(s)
- S H Adams
- Unit of Biochemistry, School of Pharmacy, University of Barcelona, Avda. Diagonal, 643, 08028 Barcelona, Spain
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