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Hughey CC, Bracy DP, Rome FI, Goelzer M, Donahue EP, Viollet B, Foretz M, Wasserman DH. Exercise training adaptations in liver glycogen and glycerolipids require hepatic AMP-activated protein kinase in mice. Am J Physiol Endocrinol Metab 2024; 326:E14-E28. [PMID: 37938177 DOI: 10.1152/ajpendo.00289.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 11/06/2023] [Accepted: 11/06/2023] [Indexed: 11/09/2023]
Abstract
Regular exercise elicits adaptations in glucose and lipid metabolism that allow the body to meet energy demands of subsequent exercise bouts more effectively and mitigate metabolic diseases including fatty liver. Energy discharged during the acute exercise bouts that comprise exercise training may be a catalyst for liver adaptations. During acute exercise, liver glycogenolysis and gluconeogenesis are accelerated to supply glucose to working muscle. Lower liver energy state imposed by gluconeogenesis and related pathways activates AMP-activated protein kinase (AMPK), which conserves ATP partly by promoting lipid oxidation. This study tested the hypothesis that AMPK is necessary for liver glucose and lipid adaptations to training. Liver-specific AMPKα1α2 knockout (AMPKα1α2fl/fl+AlbCre) mice and littermate controls (AMPKα1α2fl/fl) completed sedentary and exercise training protocols. Liver nutrient fluxes were quantified at rest or during acute exercise following training. Liver metabolites and molecular regulators of metabolism were assessed. Training increased liver glycogen in AMPKα1α2fl/fl mice, but not in AMPKα1α2fl/fl+AlbCre mice. The inability to increase glycogen led to lower glycogenolysis, glucose production, and circulating glucose during acute exercise in trained AMPKα1α2fl/fl+AlbCre mice. Deletion of AMPKα1α2 attenuated training-induced declines in liver diacylglycerides. In particular, training lowered the concentration of unsaturated and elongated fatty acids comprising diacylglycerides in AMPKα1α2fl/fl mice, but not in AMPKα1α2fl/fl+AlbCre mice. Training increased liver triacylglycerides and the desaturation and elongation of fatty acids in triacylglycerides of AMPKα1α2fl/fl+AlbCre mice. These lipid responses were independent of differences in tricarboxylic acid cycle fluxes. In conclusion, AMPK is required for liver training adaptations that are critical to glucose and lipid metabolism.NEW & NOTEWORTHY This study shows that the energy sensor and transducer, AMP-activated protein kinase (AMPK), is necessary for an exercise training-induced: 1) increase in liver glycogen that is necessary for accelerated glycogenolysis during exercise, 2) decrease in liver glycerolipids independent of tricarboxylic acid (TCA) cycle flux, and 3) decline in the desaturation and elongation of fatty acids comprising liver diacylglycerides. The mechanisms defined in these studies have implications for use of regular exercise or AMPK-activators in patients with fatty liver.
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Affiliation(s)
- Curtis C Hughey
- Division of Molecular Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, United States
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, United States
| | - Deanna P Bracy
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, United States
- Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, Tennessee, United States
| | - Ferrol I Rome
- Division of Molecular Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, United States
| | - Mickael Goelzer
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, United States
| | - E Patrick Donahue
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, United States
| | - Benoit Viollet
- Université Paris Cité, CNRS, Inserm, Institut Cochin, Paris, France
| | - Marc Foretz
- Université Paris Cité, CNRS, Inserm, Institut Cochin, Paris, France
| | - David H Wasserman
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, United States
- Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, Tennessee, United States
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Guo Q, Yen CN, Scheffler TL, Richert BT, Schinckel AP, Grant AL, Gerrard DE. Ractopamine does not rescue Halothane and Rendement Napole metabolism postmortem. Meat Sci 2023; 198:109075. [PMID: 36641987 DOI: 10.1016/j.meatsci.2022.109075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 11/28/2022] [Accepted: 12/11/2022] [Indexed: 12/15/2022]
Abstract
The objective of this study was to determine if ractopamine (RAC) impacts postmortem muscle metabolism and subsequent pork quality in Halothane (HAL) and Rendement Napole (RN) mutant pigs. All RAC fed pigs had increased (P < 0.04) L* values. HAL and RN mutants muscle had lower (P < 0.01) pH values but RAC feeding had no effect. RN mutants had higher and lower (P < 0.05) muscle pH and temperatures, respectfully at 15 min and RN mutant pigs had greater (P < 0.0001) glycogen initially but lactate levels similar to wild type (WT) pigs at 24 h. RAC lowered (P < 0.05) glycogen in RN mutants but not in HAL mutated or WT pig muscle. These data show RAC feeding changes postmortem energy metabolism but does not change pH and pork quality hallmark of two major pig gene mutations and supports our contention that ultimate meat quality traits and their biochemical drivers may be more complex than originally reasoned.
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Affiliation(s)
- Q Guo
- Department of Animal Sciences, Purdue University, W. Lafayette, IN 47907, United States of America
| | - C-N Yen
- School of Animal Sciences, Virginia Tech, Blacksburg, VA 24601, United States of America
| | - T L Scheffler
- Department of Animal Sciences, Purdue University, W. Lafayette, IN 47907, United States of America
| | - B T Richert
- Department of Animal Sciences, Purdue University, W. Lafayette, IN 47907, United States of America
| | - A P Schinckel
- Department of Animal Sciences, Purdue University, W. Lafayette, IN 47907, United States of America
| | - A L Grant
- School of Animal Sciences, Virginia Tech, Blacksburg, VA 24601, United States of America
| | - D E Gerrard
- School of Animal Sciences, Virginia Tech, Blacksburg, VA 24601, United States of America.
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Zurbrigg K, Bertolini F, Walugembe M, van Dreumel T, Alves D, Friendship R, O'Sullivan TL, Rothschild MF. A genome-wide analysis of cardiac lesions of pigs that die during transport: Is heart failure of in-transit-loss pigs associated with a heritable cardiomyopathy? CANADIAN JOURNAL OF VETERINARY RESEARCH = REVUE CANADIENNE DE RECHERCHE VETERINAIRE 2021; 85:119-126. [PMID: 33883819 PMCID: PMC7995549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 09/25/2020] [Indexed: 06/12/2023]
Abstract
While heart failure is a primary cause of death for many in-transit-loss (ITL) pigs, the underlying cause of these deaths is not known. Cardiomyopathies are considered a common cause of heart failure in humans and often have a genetic component. The objective of this study was to determine if genes associated with cardiomyopathies could be identified in ITL pigs. Samples from the hearts of pigs that died during transport to an abattoir in Ontario, Canada were collected and genotyped along with samples from pigs that did not die during transport (ILT hearts: n = 149; non-ITL/control hearts: n = 387). Genome-wide analyses were carried out on each of the determined phenotypes (gross cardiac lesions) using a medium density single nucleotide polymorphism (SNP) chip and 500 kb windows/regions for analysis, with 250 kb regions of overlap. The distribution derived by a multidimensional scaling (MDS) analysis of all phenotypes demonstrated a lack of complete separation between phenotypes of affected and unaffected animals, which made diagnosis difficult. Although genetic differences were small, a few genes associated with dilated cardiomyopathy (DCM) and arrhythmogenic right ventricular cardiomyopathy (ARVM) were identified. In addition, multiple genes associated with cardiac arrhythmias and ventricular hypertrophy were identified that can possibly result in heart failure. The results of this preliminary study did not provide convincing evidence that a single, heritable cardiomyopathy is the cause of heart failure in ITL pigs.
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Affiliation(s)
- Katherine Zurbrigg
- Department of Population Medicine, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1 (Zurbrigg, Friendship, O'Sullivan); Department of Animal Science, Iowa State University, Ames, Iowa 50011, USA (Bertolini, Walugembe, Rothschild); National Institute of Aquatic Resources, Technical University of Denmark, Lyngby, Denmark (Bertolini); Veterinary Pathology Consultant, Ontario (van Dreumel), Veterinary Epidemiology Consultant, Elora, Ontario (Alves)
| | - Francesca Bertolini
- Department of Population Medicine, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1 (Zurbrigg, Friendship, O'Sullivan); Department of Animal Science, Iowa State University, Ames, Iowa 50011, USA (Bertolini, Walugembe, Rothschild); National Institute of Aquatic Resources, Technical University of Denmark, Lyngby, Denmark (Bertolini); Veterinary Pathology Consultant, Ontario (van Dreumel), Veterinary Epidemiology Consultant, Elora, Ontario (Alves)
| | - Muhammed Walugembe
- Department of Population Medicine, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1 (Zurbrigg, Friendship, O'Sullivan); Department of Animal Science, Iowa State University, Ames, Iowa 50011, USA (Bertolini, Walugembe, Rothschild); National Institute of Aquatic Resources, Technical University of Denmark, Lyngby, Denmark (Bertolini); Veterinary Pathology Consultant, Ontario (van Dreumel), Veterinary Epidemiology Consultant, Elora, Ontario (Alves)
| | - Toni van Dreumel
- Department of Population Medicine, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1 (Zurbrigg, Friendship, O'Sullivan); Department of Animal Science, Iowa State University, Ames, Iowa 50011, USA (Bertolini, Walugembe, Rothschild); National Institute of Aquatic Resources, Technical University of Denmark, Lyngby, Denmark (Bertolini); Veterinary Pathology Consultant, Ontario (van Dreumel), Veterinary Epidemiology Consultant, Elora, Ontario (Alves)
| | - David Alves
- Department of Population Medicine, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1 (Zurbrigg, Friendship, O'Sullivan); Department of Animal Science, Iowa State University, Ames, Iowa 50011, USA (Bertolini, Walugembe, Rothschild); National Institute of Aquatic Resources, Technical University of Denmark, Lyngby, Denmark (Bertolini); Veterinary Pathology Consultant, Ontario (van Dreumel), Veterinary Epidemiology Consultant, Elora, Ontario (Alves)
| | - Robert Friendship
- Department of Population Medicine, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1 (Zurbrigg, Friendship, O'Sullivan); Department of Animal Science, Iowa State University, Ames, Iowa 50011, USA (Bertolini, Walugembe, Rothschild); National Institute of Aquatic Resources, Technical University of Denmark, Lyngby, Denmark (Bertolini); Veterinary Pathology Consultant, Ontario (van Dreumel), Veterinary Epidemiology Consultant, Elora, Ontario (Alves)
| | - Terri L O'Sullivan
- Department of Population Medicine, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1 (Zurbrigg, Friendship, O'Sullivan); Department of Animal Science, Iowa State University, Ames, Iowa 50011, USA (Bertolini, Walugembe, Rothschild); National Institute of Aquatic Resources, Technical University of Denmark, Lyngby, Denmark (Bertolini); Veterinary Pathology Consultant, Ontario (van Dreumel), Veterinary Epidemiology Consultant, Elora, Ontario (Alves)
| | - Max F Rothschild
- Department of Population Medicine, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1 (Zurbrigg, Friendship, O'Sullivan); Department of Animal Science, Iowa State University, Ames, Iowa 50011, USA (Bertolini, Walugembe, Rothschild); National Institute of Aquatic Resources, Technical University of Denmark, Lyngby, Denmark (Bertolini); Veterinary Pathology Consultant, Ontario (van Dreumel), Veterinary Epidemiology Consultant, Elora, Ontario (Alves)
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Inducible deletion of skeletal muscle AMPKα reveals that AMPK is required for nucleotide balance but dispensable for muscle glucose uptake and fat oxidation during exercise. Mol Metab 2020; 40:101028. [PMID: 32504885 PMCID: PMC7356270 DOI: 10.1016/j.molmet.2020.101028] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/25/2020] [Accepted: 05/26/2020] [Indexed: 02/05/2023] Open
Abstract
Objective Evidence for AMP-activated protein kinase (AMPK)-mediated regulation of skeletal muscle metabolism during exercise is mainly based on transgenic mouse models with chronic (lifelong) disruption of AMPK function. Findings based on such models are potentially biased by secondary effects related to a chronic lack of AMPK function. To study the direct effect(s) of AMPK on muscle metabolism during exercise, we generated a new mouse model with inducible muscle-specific deletion of AMPKα catalytic subunits in adult mice. Methods Tamoxifen-inducible and muscle-specific AMPKα1/α2 double KO mice (AMPKα imdKO) were generated by using the Cre/loxP system, with the Cre under the control of the human skeletal muscle actin (HSA) promoter. Results During treadmill running at the same relative exercise intensity, AMPKα imdKO mice showed greater depletion of muscle ATP, which was associated with accumulation of the deamination product IMP. Muscle-specific deletion of AMPKα in adult mice promptly reduced maximal running speed and muscle glycogen content and was associated with reduced expression of UGP2, a key component of the glycogen synthesis pathway. Muscle mitochondrial respiration, whole-body substrate utilization, and muscle glucose uptake and fatty acid (FA) oxidation during muscle contractile activity remained unaffected by muscle-specific deletion of AMPKα subunits in adult mice. Conclusions Inducible deletion of AMPKα subunits in adult mice reveals that AMPK is required for maintaining muscle ATP levels and nucleotide balance during exercise but is dispensable for regulating muscle glucose uptake, FA oxidation, and substrate utilization during exercise. Inducible deletion of AMPKα in adult mice disturbs nucleotide balance during exercise. Inducible deletion of AMPKα in adult mice lowers muscle glycogen content and reduces exercise capacity. Muscle mitochondrial respiration, and glucose uptake and FA oxidation during muscle contractions remain unaffected by AMPKα deletion.
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Poleti MD, Moncau CT, Silva-Vignato B, Rosa AF, Lobo AR, Cataldi TR, Negrão JA, Silva SL, Eler JP, de Carvalho Balieiro JC. Label-free quantitative proteomic analysis reveals muscle contraction and metabolism proteins linked to ultimate pH in bovine skeletal muscle. Meat Sci 2018; 145:209-219. [DOI: 10.1016/j.meatsci.2018.06.041] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 06/28/2018] [Accepted: 06/28/2018] [Indexed: 12/23/2022]
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Huang H, Scheffler TL, Gerrard DE, Larsen MR, Lametsch R. Quantitative Proteomics and Phosphoproteomics Analysis Revealed Different Regulatory Mechanisms of Halothane and Rendement Napole Genes in Porcine Muscle Metabolism. J Proteome Res 2018; 17:2834-2849. [PMID: 29916714 DOI: 10.1021/acs.jproteome.8b00294] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Pigs with the Halothane (HAL) or Rendement Napole (RN) gene mutations demonstrate abnormal muscle energy metabolism patterns and produce meat with poor quality, classified as pale, soft, and exudative (PSE) meat, but it is not well understood how HAL and RN mutations regulate glucose and energy metabolism in porcine muscle. To investigate the potential signaling pathways and phosphorylation events related to these mutations, muscle samples were collected from four genotypes of pigs, wild type, RN, HAL, and RN-HAL double mutations, and subjected to quantitative proteomic and phosphoproteomic analysis using the TiO2 enrichment strategy. The study led to the identification of 932 proteins from the nonmodified peptide fractions and 1885 phosphoproteins with 9619 phosphorylation sites from the enriched fractions. Among them, 128 proteins at total protein level and 323 phosphosites from 91 phosphoproteins were significantly regulated in mutant genotypes. The quantitative analysis revealed that the RN mutation mainly affected the protein expression abundance in muscle. Specifically, high expression was observed for proteins related to mitochondrial respiratory chain and energy metabolism, thereby enhancing the muscle oxidative capacity. The high content of UDP-glucose pyrophosphorylase 2 (UGP2) in RN mutant animals may contribute to high glycogen storage. However, the HAL mutation mainly contributes to the up-regulation of phosphorylation in proteins related to calcium signaling, muscle contraction, glycogen, glucose, and energy metabolism, and cellular stress. The increased phosphorylation of Ca2+/calmodulin-dependent protein kinase II (CAMK2) in HAL mutation may act as a key regulator in these processes of muscle. Our findings indicate the different regulatory mechanisms of RN and HAL mutations in relation to porcine muscle energy metabolism and meat quality.
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Affiliation(s)
- Honggang Huang
- Department of Biochemistry and Molecular Biology , University of Southern Denmark , DK-5230 Odense M , Denmark.,Department of Food Science, Faculty of Science , University of Copenhagen , DK-1958 Frederiksberg , Denmark.,The Danish Diabetes Academy , 5000 Odense , Denmark.,Arla Foods Ingredients Group P/S , Soenderupvej 26 , 6920 Videbaek , Denmark
| | - Tracy L Scheffler
- Department of Animal Sciences , University of Florida , Gainesville , Florida 32608 , United States
| | - David E Gerrard
- Department of Animal and Poultry Sciences , Virginia Tech , Blacksburg , Virginia 24061 , United States
| | - Martin R Larsen
- Department of Biochemistry and Molecular Biology , University of Southern Denmark , DK-5230 Odense M , Denmark
| | - René Lametsch
- Department of Food Science, Faculty of Science , University of Copenhagen , DK-1958 Frederiksberg , Denmark
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7
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Chen C, Yan T, Liu L, Wang J, Jin Q. Identification of a Novel Serum Biomarker for Tuberculosis Infection in Chinese HIV Patients by iTRAQ-Based Quantitative Proteomics. Front Microbiol 2018. [PMID: 29535695 PMCID: PMC5834467 DOI: 10.3389/fmicb.2018.00330] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Tuberculosis (TB) is a major comorbidity in HIV patients as well as a serious co-epidemic. Traditional detection methods are not effective or sensitive for the detection of Mycobacterium tuberculosis at the early stage. TB has become a major cause of lethal on HIV patients. We employed isobaric tags for relative and absolute quantitation (iTRAQ) technology to identify the different host responses in HIV-noTB and HIV-TB patients’ sera. Given the diversity of HIV subtypes, which results in a variety of host responses in different human populations, we focused on the Chinese patients. Of the 25 proteins identified, 7 were increased and 18 were decreased in HIV-TB co-infected patients. These proteins were found to be involved in host immune response processes. We identified a candidate protein, endoglin (ENG), which showed an 4.9 times increase by iTRAQ and 11.5 times increase by ELISA. ENG demonstrated the diagnostic efficacy and presented a novel molecular biomarker for TB in HIV-infected Chinese patients. This study provides new insight into the challenges in the diagnosis and effective management of patients with HIV-TB.
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Affiliation(s)
- Cong Chen
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Tao Yan
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Liguo Liu
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jianmin Wang
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Qi Jin
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
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Hughey CC, James FD, Bracy DP, Donahue EP, Young JD, Viollet B, Foretz M, Wasserman DH. Loss of hepatic AMP-activated protein kinase impedes the rate of glycogenolysis but not gluconeogenic fluxes in exercising mice. J Biol Chem 2017; 292:20125-20140. [PMID: 29038293 DOI: 10.1074/jbc.m117.811547] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 10/10/2017] [Indexed: 11/06/2022] Open
Abstract
Pathologies including diabetes and conditions such as exercise place an unusual demand on liver energy metabolism, and this demand induces a state of energy discharge. Hepatic AMP-activated protein kinase (AMPK) has been proposed to inhibit anabolic processes such as gluconeogenesis in response to cellular energy stress. However, both AMPK activation and glucose release from the liver are increased during exercise. Here, we sought to test the role of hepatic AMPK in the regulation of in vivo glucose-producing and citric acid cycle-related fluxes during an acute bout of muscular work. We used 2H/13C metabolic flux analysis to quantify intermediary metabolism fluxes in both sedentary and treadmill-running mice. Additionally, liver-specific AMPK α1 and α2 subunit KO and WT mice were utilized. Exercise caused an increase in endogenous glucose production, glycogenolysis, and gluconeogenesis from phosphoenolpyruvate. Citric acid cycle fluxes, pyruvate cycling, anaplerosis, and cataplerosis were also elevated during this exercise. Sedentary nutrient fluxes in the postabsorptive state were comparable for the WT and KO mice. However, the increment in the endogenous rate of glucose appearance during exercise was blunted in the KO mice because of a diminished glycogenolytic flux. This lower rate of glycogenolysis was associated with lower hepatic glycogen content before the onset of exercise and prompted a reduction in arterial glucose during exercise. These results indicate that liver AMPKα1α2 is required for maintaining glucose homeostasis during an acute bout of exercise.
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Affiliation(s)
- Curtis C Hughey
- Department of Molecular Physiology and Biophysics, Nashville, Tennessee 37232
| | - Freyja D James
- Department of Molecular Physiology and Biophysics, Nashville, Tennessee 37232; Mouse Metabolic Phenotyping Center, Nashville, Tennessee 37232
| | - Deanna P Bracy
- Department of Molecular Physiology and Biophysics, Nashville, Tennessee 37232; Mouse Metabolic Phenotyping Center, Nashville, Tennessee 37232
| | - E Patrick Donahue
- Department of Molecular Physiology and Biophysics, Nashville, Tennessee 37232
| | - Jamey D Young
- Department of Molecular Physiology and Biophysics, Nashville, Tennessee 37232; Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37232
| | - Benoit Viollet
- INSERM, U1016, Institut Cochin, 75014 Paris, France; CNRS, UMR 8104, 75014 Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75014 Paris, France
| | - Marc Foretz
- INSERM, U1016, Institut Cochin, 75014 Paris, France; CNRS, UMR 8104, 75014 Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75014 Paris, France
| | - David H Wasserman
- Department of Molecular Physiology and Biophysics, Nashville, Tennessee 37232; Mouse Metabolic Phenotyping Center, Nashville, Tennessee 37232.
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Silvestri S, Lepri E, Dall'Aglio C, Marchesi MC, Vitellozzi G. Nuclear Glycogen Inclusions in Canine Parietal Cells. Vet Pathol 2017; 54:520-526. [PMID: 28113038 DOI: 10.1177/0300985816688944] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Nuclear glycogen inclusions occur infrequently in pathologic conditions but also in normal human and animal tissues. Their function or significance is unclear. To the best of the authors' knowledge, no reports of nuclear glycogen inclusions in canine parietal cells exist. After initial observations of nuclear inclusions/pseudoinclusions during routine histopathology, the authors retrospectively examined samples of gastric mucosa from dogs presenting with gastrointestinal signs for the presence of intranuclear inclusions/pseudoinclusions and determined their composition using histologic and electron-microscopic methods. In 24 of 108 cases (22%), the authors observed various numbers of intranuclear inclusions/pseudoinclusions within scattered parietal cells. Nuclei were characterized by marked karyomegaly and chromatin margination around a central optically empty or slightly eosinophilic area. The intranuclear inclusions/pseudoinclusions stained positive with periodic acid-Schiff (PAS) and were diastase sensitive, consistent with glycogen. Several PAS-positive/diastase-sensitive sections were further examined by transmission electron microscopy, also using periodic acid-thiocarbohydrazide-silver proteinate (PA-TCH-SP) staining to identify polysaccharides. Ultrastructurally, the nuclear inclusions were composed of electron-dense particles that were not membrane bound, without evidence of nuclear membrane invaginations or cytoplasmic organelles in the nuclei, and positive staining with PA-TCH-SP, confirming a glycogen composition. No cytoplasmic glycogen deposits were observed, suggesting that the intranuclear glycogen inclusions were probably synthesized in loco. Nuclear glycogen inclusions were not associated with gastritis or colonization by Helicobacter-like organisms ( P > .05). Our findings suggest that nuclear glycogen inclusions in canine parietal cells could be an incidental finding. Nevertheless, since nuclear glycogen is present in several pathologic conditions, further investigations could be warranted to determine their true significance.
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Affiliation(s)
- S Silvestri
- 1 Department of Veterinary Medicine, University of Perugia, Perugia, Italy
| | - E Lepri
- 1 Department of Veterinary Medicine, University of Perugia, Perugia, Italy
| | - C Dall'Aglio
- 1 Department of Veterinary Medicine, University of Perugia, Perugia, Italy
| | - M C Marchesi
- 1 Department of Veterinary Medicine, University of Perugia, Perugia, Italy
| | - G Vitellozzi
- 1 Department of Veterinary Medicine, University of Perugia, Perugia, Italy
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Scheffler TL, Park S, Roach PJ, Gerrard DE. Gain of function AMP-activated protein kinase γ3 mutation (AMPKγ3R200Q) in pig muscle increases glycogen storage regardless of AMPK activation. Physiol Rep 2016; 4:4/11/e12802. [PMID: 27302990 PMCID: PMC4908487 DOI: 10.14814/phy2.12802] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 04/28/2016] [Indexed: 01/18/2023] Open
Abstract
Chronic activation of AMP‐activated protein kinase (AMPK) increases glycogen content in skeletal muscle. Previously, we demonstrated that a mutation in the ryanodine receptor (RyR1R615C) blunts AMPK phosphorylation in longissimus muscle of pigs with a gain of function mutation in the AMPKγ3 subunit (AMPKγ3R200Q); this may decrease the glycogen storage capacity of AMPKγ3R200Q + RyR1R615C muscle. Therefore, our aim in this study was to utilize our pig model to understand how AMPKγ3R200Q and AMPK activation contribute to glycogen storage and metabolism in muscle. We selected and bred pigs in order to generate offspring with naturally occurring AMPKγ3R200Q, RyR1R615C, and AMPKγ3R200Q + RyR1R615C mutations, and also retained wild‐type littermates (control). We assessed glycogen content and parameters of glycogen metabolism in longissimus muscle. Regardless of RyR1R615C, AMPKγ3R200Q increased the glycogen content by approximately 70%. Activity of glycogen synthase (GS) without the allosteric activator glucose 6‐phosphate (G6P) was decreased in AMPKγ3R200Q relative to all other genotypes, whereas both AMPKγ3R200Q and AMPKγ3R200Q + RyR1R615C muscle exhibited increased GS activity with G6P. Increased activity of GS with G6P was not associated with increased abundance of GS or hexokinase 2. However, AMPKγ3R200Q enhanced UDP‐glucose pyrophosphorylase 2 (UGP2) expression approximately threefold. Although UGP2 is not generally considered a rate‐limiting enzyme for glycogen synthesis, our model suggests that UGP2 plays an important role in increasing flux to glycogen synthase. Moreover, we have shown that the capacity for glycogen storage is more closely related to the AMPKγ3R200Q mutation than activity.
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Affiliation(s)
- Tracy L Scheffler
- Department of Animal and Poultry Sciences, Litton-Reaves Hall, Virginia Tech, Blacksburg, Virginia
| | - Sungkwon Park
- Department of Animal and Poultry Sciences, Litton-Reaves Hall, Virginia Tech, Blacksburg, Virginia
| | - Peter J Roach
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
| | - David E Gerrard
- Department of Animal and Poultry Sciences, Litton-Reaves Hall, Virginia Tech, Blacksburg, Virginia
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