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Tran M, Gilling S, Wu J, Wang L, Shin DJ. miR-141/200c contributes to ethanol-mediated hepatic glycogen metabolism. Mol Metab 2024; 84:101942. [PMID: 38642890 PMCID: PMC11060962 DOI: 10.1016/j.molmet.2024.101942] [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: 04/04/2024] [Accepted: 04/15/2024] [Indexed: 04/22/2024] Open
Abstract
OBJECTIVE Hepatic glucose metabolism is profoundly perturbed by excessive alcohol intake. miR-141/200c expression is significantly induced by chronic ethanol feeding. This study aimed at identifying the role of miR-141/200c in glucose homeostasis during chronic ethanol exposure. METHODS WT and miR-141/200c KO mice were fed a control or an ethanol diet for 30 days, followed by a single binge of maltose dextrin or ethanol, respectively. Untargeted metabolomics analysis of hepatic primary metabolites was performed along with analyses for liver histology, gene expression, intracellular signaling pathways, and physiological relevance. Primary hepatocytes were used for mechanistic studies. RESULTS miR-141/200c deficiency rewires hepatic glucose metabolism during chronic ethanol feeding, increasing the abundance of glucose intermediates including G6P, an allosteric activator for GS. miR-141/200c deficiency replenished glycogen depletion during chronic ethanol feeding accompanied by reduced GS phosphorylation in parallel with increased expression of PP1 glycogen targeting subunits. Moreover, miR-141/200c deficiency prevented ethanol-mediated increases in AMPK and CaMKK2 activity. Ethanol treatment reduced glycogen content in WT-hepatocytes, which was reversed by dorsomorphin, a selective AMPK inhibitor, while KO-hepatocytes displayed higher glycogen content than WT-hepatocytes in response to ethanol treatment. Furthermore, treatment of hepatocytes with A23187, a calcium ionophore activating CaMKK2, lowered glycogen content in WT-hepatocytes. Notably, the suppressive effect of A23187 on glycogen deposition was reversed by dorsomorphin, demonstrating that the glycogen depletion by A23187 is mediated by AMPK. KO-hepatocytes exhibited higher glycogen content than WT-hepatocytes in response to A23187. Finally, miR-141/200c deficiency led to improved glucose tolerance and insulin sensitivity during chronic ethanol feeding. CONCLUSIONS miR-141/200c deficiency replenishes ethanol-mediated hepatic glycogen depletion through the regulation of GS activity and calcium signaling coupled with the AMPK pathway, improving glucose homeostasis and insulin sensitivity. These results underscore miR-141/200c as a potential therapeutic target for the management of alcohol intoxication.
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Affiliation(s)
- Melanie Tran
- Department of Physiology and Neurobiology, University of Connecticut, 75 N. Eagleville Rd, Storrs, CT 06269, USA
| | - Shaynian Gilling
- Department of Physiology and Neurobiology, University of Connecticut, 75 N. Eagleville Rd, Storrs, CT 06269, USA
| | - Jianguo Wu
- Department of Physiology and Neurobiology, University of Connecticut, 75 N. Eagleville Rd, Storrs, CT 06269, USA
| | - Li Wang
- Department of Internal Medicine, Section of Digestive Diseases, Yale University, 333 Cedar St, New Haven, CT 06510, USA
| | - Dong-Ju Shin
- Department of Physiology and Neurobiology, University of Connecticut, 75 N. Eagleville Rd, Storrs, CT 06269, USA.
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Chen J, Ji X, Gao J, Huang J, Ren J. gys1 regulates maternal glycogen reserve essential for embryonic development in zebrafish. Heliyon 2024; 10:e31149. [PMID: 38803914 PMCID: PMC11128933 DOI: 10.1016/j.heliyon.2024.e31149] [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: 08/10/2023] [Revised: 05/10/2024] [Accepted: 05/10/2024] [Indexed: 05/29/2024] Open
Abstract
The reserve of glycogen is essential for embryonic development. In oviparous fish, egg is an isolated system after egg laying with all the required energy deposits by their mothers. However, the key regulated factor mediates the storage of maternal glycogen reserve which support for embryogenesis in the offspring is largely unknown. Glycogen synthase (GYS) is a central enzyme for glycogen synthesis. In our previous study, we generated a gys1 knockout zebrafish line, showed an embryonic developmental defect in F3 generation. In this study, firstly we determined that the gys1 was maternal origin by backcrossing the F2 mutant with wildtype lines. PAS staining and glycogen content measurement showed that glycogen reserve was reduced both in ovaries and embryos in the mutant group compared to wildtypes. Free glucose measurement analysis showed a 50 % of reduction in gys1 mutant embryos compared to wildtype embryos at 24 hpf; showed an approximal 50 % of reduction in gys1 mutant adults compared to wildtypes. Microinjection of 2-NBDG in embryos and comparison of fluorescent signal demonstrated that glucose uptake ability was decreased in the mutant embryos, indicating an impaired glucose metabolism. Untargeted metabolomics analysis then was employed and revealed that key modified metabolites enriched into vitamin B pathway, carbohydrate and unsaturated fatty acid pathways. These results demonstrated that gys1 played a role on glycogen metabolism, involved into the maternal glycogen reserve which essentially contribute to embryonic development.
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Affiliation(s)
- Jie Chen
- International Research Center for Marine Biosciences, Ministry of Science and Technology and National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
- CCMAR/CIMAR Centro de Ciências do Mar do Algarve, Universidade do Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
| | - Xiao Ji
- International Research Center for Marine Biosciences, Ministry of Science and Technology and National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
| | - Jing Gao
- International Research Center for Marine Biosciences, Ministry of Science and Technology and National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
| | - Jiao Huang
- International Research Center for Marine Biosciences, Ministry of Science and Technology and National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
| | - Jianfeng Ren
- International Research Center for Marine Biosciences, Ministry of Science and Technology and National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
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3
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Żołnierkiewicz O, Rogacka D. Hyperglycemia - A culprit of podocyte pathology in the context of glycogen metabolism. Arch Biochem Biophys 2024; 753:109927. [PMID: 38350532 DOI: 10.1016/j.abb.2024.109927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 01/31/2024] [Accepted: 02/10/2024] [Indexed: 02/15/2024]
Abstract
Prolonged disruption in the balance of glucose can result in metabolic disorders. The kidneys play a significant role in regulating blood glucose levels. However, when exposed to chronic hyperglycemia, the kidneys' ability to handle glucose metabolism may be impaired, leading to an accumulation of glycogen. Earlier studies have shown that there can be a significant increase in glucose storage in the form of glycogen in the kidneys in diabetes. Podocytes play a crucial role in maintaining the integrity of filtration barrier. In diabetes, exposure to elevated glucose levels can lead to significant metabolic and structural changes in podocytes, contributing to kidney damage and the development of diabetic kidney disease. The accumulation of glycogen in podocytes is not a well-established phenomenon. However, a recent study has demonstrated the presence of glycogen granules in podocytes. This review delves into the intricate connections between hyperglycemia and glycogen metabolism within the context of the kidney, with special emphasis on podocytes. The aberrant storage of glycogen has the potential to detrimentally impact podocyte functionality and perturb their structural integrity. This review provides a comprehensive analysis of the alterations in cellular signaling pathways that may potentially lead to glycogen overproduction in podocytes.
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Affiliation(s)
- Olga Żołnierkiewicz
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Laboratory of Molecular and Cellular Nephrology, Wita Stwosza 63, 80-308, Gdansk, Poland
| | - Dorota Rogacka
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Laboratory of Molecular and Cellular Nephrology, Wita Stwosza 63, 80-308, Gdansk, Poland; University of Gdansk, Faculty of Chemistry, Department of Molecular Biotechnology, Wita Stwosza 63, 80-308, Gdansk, Poland.
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4
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Broadwin M, Harris DD, Sabe SA, Sengun E, Sylvestre AJ, Alexandrov BS, Selke FW, Usheva A. Impaired cardiac glycolysis and glycogen depletion are linked to poor myocardial outcomes in juvenile male swine with metabolic syndrome and ischemia. Physiol Rep 2023; 11:e15742. [PMID: 37537137 PMCID: PMC10400405 DOI: 10.14814/phy2.15742] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 05/18/2023] [Accepted: 05/19/2023] [Indexed: 08/05/2023] Open
Abstract
Obesity continues to rise in the juveniles and obese children are more likely to develop metabolic syndrome (MetS) and related cardiovascular disease. Unfortunately, effective prevention and long-term treatment options remain limited. We determined the juvenile cardiac response to MetS in a swine model. Juvenile male swine were fed either an obesogenic diet, to induce MetS, or a lean diet, as a control (LD). Myocardial ischemia was induced with surgically placed ameroid constrictor on the left circumflex artery. Physiological data were recorded and at 22 weeks of age the animals underwent a terminal harvest procedure and myocardial tissue was extracted for total metabolic and proteomic LC/MS-MS, RNA-seq analysis, and data underwent nonnegative matrix factorization for metabolic signatures. Significantly altered in MetS versus. LD were the glycolysis-related metabolites and enzymes. In MetS compared with LD Glycogen synthase 1 (GYS1)-glycogen phosphorylases (PYGM/PYGL) expression disbalance resulted in a loss of myocardial glycogen. Our findings are consistent with the concept that transcriptionally driven myocardial changes in glycogen and glucose metabolism-related enzymes lead to a deficiency of their metabolite products in MetS. This abnormal energy metabolism provides insight into the pathogenesis of the juvenile heart in MetS. This study reveals that MetS and ischemia diminishes ATP availability in the myocardium via altering the glucose-G6P-pyruvate axis at the level of metabolites and gene expression of related enzymes. The observed severe glycogen depletion in MetS coincides with disbalance in expression of GYS1 and both PYGM and PYGL. This altered energy substrate metabolism is a potential target of pharmacological agents for improving juvenile myocardial function in MetS and ischemia.
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Affiliation(s)
- Mark Broadwin
- Division of Cardiothoracic Surgery, Department of SurgeryWarren Alpert Medical School of Brown UniversityProvidenceRhode IslandUSA
| | - Dwight D. Harris
- Division of Cardiothoracic Surgery, Department of SurgeryWarren Alpert Medical School of Brown UniversityProvidenceRhode IslandUSA
| | - Sharif A. Sabe
- Division of Cardiothoracic Surgery, Department of SurgeryWarren Alpert Medical School of Brown UniversityProvidenceRhode IslandUSA
| | - Elif Sengun
- Division of Cardiology, Department of MedicineWarren Alpert Medical School of Brown UniversityProvidenceRhode IslandUSA
| | - Amber J. Sylvestre
- Division of Cardiothoracic Surgery, Department of SurgeryWarren Alpert Medical School of Brown UniversityProvidenceRhode IslandUSA
| | | | - Frank W. Selke
- Division of Cardiothoracic Surgery, Department of SurgeryWarren Alpert Medical School of Brown UniversityProvidenceRhode IslandUSA
| | - Anny Usheva
- Division of Cardiothoracic Surgery, Department of SurgeryWarren Alpert Medical School of Brown UniversityProvidenceRhode IslandUSA
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5
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Gümüş E, Özen H. Glycogen storage diseases: An update. World J Gastroenterol 2023; 29:3932-3963. [PMID: 37476587 PMCID: PMC10354582 DOI: 10.3748/wjg.v29.i25.3932] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 02/15/2023] [Accepted: 04/30/2023] [Indexed: 06/28/2023] Open
Abstract
Glycogen storage diseases (GSDs), also referred to as glycogenoses, are inherited metabolic disorders of glycogen metabolism caused by deficiency of enzymes or transporters involved in the synthesis or degradation of glycogen leading to aberrant storage and/or utilization. The overall estimated GSD incidence is 1 case per 20000-43000 live births. There are over 20 types of GSD including the subtypes. This heterogeneous group of rare diseases represents inborn errors of carbohydrate metabolism and are classified based on the deficient enzyme and affected tissues. GSDs primarily affect liver or muscle or both as glycogen is particularly abundant in these tissues. However, besides liver and skeletal muscle, depending on the affected enzyme and its expression in various tissues, multiorgan involvement including heart, kidney and/or brain may be seen. Although GSDs share similar clinical features to some extent, there is a wide spectrum of clinical phenotypes. Currently, the goal of treatment is to maintain glucose homeostasis by dietary management and the use of uncooked cornstarch. In addition to nutritional interventions, pharmacological treatment, physical and supportive therapies, enzyme replacement therapy (ERT) and organ transplantation are other treatment approaches for both disease manifestations and long-term complications. The lack of a specific therapy for GSDs has prompted efforts to develop new treatment strategies like gene therapy. Since early diagnosis and aggressive treatment are related to better prognosis, physicians should be aware of these conditions and include GSDs in the differential diagnosis of patients with relevant manifestations including fasting hypoglycemia, hepatomegaly, hypertransaminasemia, hyperlipidemia, exercise intolerance, muscle cramps/pain, rhabdomyolysis, and muscle weakness. Here, we aim to provide a comprehensive review of GSDs. This review provides general characteristics of all types of GSDs with a focus on those with liver involvement.
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Affiliation(s)
- Ersin Gümüş
- Department of Pediatric Gastroenterology, Hepatology and Nutrition, Hacettepe University Faculty of Medicine, Ihsan Dogramaci Children’s Hospital, Ankara 06230, Turkey
| | - Hasan Özen
- Department of Pediatric Gastroenterology, Hepatology and Nutrition, Hacettepe University Faculty of Medicine, Ihsan Dogramaci Children’s Hospital, Ankara 06230, Turkey
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6
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Dayan J, Melkman-Zehavi T, Reicher N, Braun U, Inhuber V, Mabjeesh SJ, Halevy O, Uni Z. Supply and demand of creatine and glycogen in broiler chicken embryos. Front Physiol 2023; 14:1079638. [PMID: 36760526 PMCID: PMC9902709 DOI: 10.3389/fphys.2023.1079638] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 01/11/2023] [Indexed: 01/25/2023] Open
Abstract
Optimal embryonic development and growth of meat-type chickens (broilers) rely on incubation conditions (oxygen, heat, and humidity), on nutrients and on energy resources within the egg. Throughout incubation and according to the embryo's energy balance, the main energy storage molecules (creatine and glycogen) are continuously utilized and synthesized, mainly in the embryonic liver, breast muscle, and the extraembryonic yolk sac (YS) tissue. During the last phase of incubation, as the embryo nears hatching, dynamic changes in energy metabolism occur. These changes may affect embryonic survival, hatchlings' uniformity, quality and post hatch performance of broilers, hence, being of great importance to poultry production. Here, we followed the dynamics of creatine and glycogen from embryonic day (E) 11 until hatch and up to chick placement at the farm. We showed that creatine is stored mainly in the breast muscle while glycogen is stored mainly in the YS tissue. Analysis of creatine synthesis genes revealed their expression in the liver, kidney, YS tissue and in the breast muscle, suggesting a full synthesis capacity in these tissues. Expression analysis of genes involved in gluconeogenesis, glycogenesis, and glycogenolysis, revealed that glycogen metabolism is most active in the liver. Nevertheless, due to the relatively large size of the breast muscle and YS tissue, their contribution to glycogen metabolism in embryos is valuable. Towards hatch, post E19, creatine levels in all tissues increased while glycogen levels dramatically decreased and reached low levels at hatch and at chick placement. This proves the utmost importance of creatine in energy supply to late-term embryos and hatchlings.
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Affiliation(s)
- Jonathan Dayan
- Department of Animal Science, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Tal Melkman-Zehavi
- Department of Animal Science, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Naama Reicher
- Department of Animal Science, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | | | | | - Sameer J. Mabjeesh
- Department of Animal Science, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Orna Halevy
- Department of Animal Science, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Zehava Uni
- Department of Animal Science, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel,*Correspondence: Zehava Uni,
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7
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Mechanism of glycogen synthase inactivation and interaction with glycogenin. Nat Commun 2022; 13:3372. [PMID: 35690592 PMCID: PMC9188544 DOI: 10.1038/s41467-022-31109-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 06/02/2022] [Indexed: 11/08/2022] Open
Abstract
Glycogen is the major glucose reserve in eukaryotes, and defects in glycogen metabolism and structure lead to disease. Glycogenesis involves interaction of glycogenin (GN) with glycogen synthase (GS), where GS is activated by glucose-6-phosphate (G6P) and inactivated by phosphorylation. We describe the 2.6 Å resolution cryo-EM structure of phosphorylated human GS revealing an autoinhibited GS tetramer flanked by two GN dimers. Phosphorylated N- and C-termini from two GS protomers converge near the G6P-binding pocket and buttress against GS regulatory helices. This keeps GS in an inactive conformation mediated by phospho-Ser641 interactions with a composite “arginine cradle”. Structure-guided mutagenesis perturbing interactions with phosphorylated tails led to increased basal/unstimulated GS activity. We propose that multivalent phosphorylation supports GS autoinhibition through interactions from a dynamic “spike” region, allowing a tuneable rheostat for regulating GS activity. This work therefore provides insights into glycogen synthesis regulation and facilitates studies of glycogen-related diseases. Glycogen is a major energy reserve in eukaryotes and is synthesised in part by glycogenin (GN) and glycogen synthase (GS). Here, authors describe the structural basis of GS regulation, specifically the mechanism of inactivation by phosphorylation.
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8
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Abbaszade Z, Bagca BG, Avci CB. Molecular biological investigation of temozolomide and KC7F2 combination in U87MG glioma cell line. Gene 2021; 776:145445. [PMID: 33484758 DOI: 10.1016/j.gene.2021.145445] [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: 05/15/2020] [Revised: 12/25/2020] [Accepted: 01/13/2021] [Indexed: 11/25/2022]
Abstract
Glioblastom Multiforme (GBM) is the most invasive and malignant member of the IV grade of the subclass Astrocytoma according to the last assessment of the 2016 WHO report. Due to the resistance to treatment and weak response, as well as the topographical structure of the blood brain barrier, the treatment is also difficult due to the severe clinical manifestation, and new treatment methods and new therapeutic agents are needed. Temozolomide (TMZ) is widely used in the treatment of glioblastoma and is considered as the primary treatment modality. TMZ, a member of the class of cognitive agents, is currently considered the most effective drug because it can easily pass through the blood brain barrier. Glucose metabolism is a complex energy producing machine that, a glucose molecule produces 38 molecules of ATP after full glycolytic catabolism. According to Otto Warburg's numerous studies cancer cells perform the first glycolytic step without entering the mitochondrial step. These cells produce lactic acid and make the micro-media more acidic even in aerobic conditions. This phenomenon is attributed to the Warburg hypothesis and either as aerobic glycolysis. Although glycolysis enzymes are the primary actors of this phenotypic expression, some genetic and epigenetic factors are no exception. We experimentally used KC7F2 active ingredient to target cancer metabolism. In our study, we evaluated cancer metabolism in combination with the effect of TMZ chemotherapeutic agent, examining the effect of two different agents separately and in combination to observe the effects of cancer cell proliferation, survival, apoptosis and expression of metabolism genes on expression. We observed that the combined effect of reduced the effective dose of the TMZ alkylating agent and that the effect was increased and the effect of the combined teraphy is assessed from a metabolic point of view and that it suppresses aerobic glycolysis.
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Affiliation(s)
- Zaka Abbaszade
- Kazımdirik, Ege Ünv. Hst. No:9, 35100 Bornova/Izmir, Turkey.
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9
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Ali A, Swanepoel CM, Winger QA, Rozance PJ, Anthony RV. Chorionic somatomammotropin RNA interference alters fetal liver glucose utilization. J Endocrinol 2020; 247:251-262. [PMID: 33108344 PMCID: PMC7643541 DOI: 10.1530/joe-20-0375] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 09/22/2020] [Indexed: 12/20/2022]
Abstract
Chorionic somatomammotropin (CSH) is a placenta-specific hormone associated with fetal growth, and fetal and maternal metabolism in both humans and sheep. We hypothesized that CSH deficiency could impact sheep fetal liver glucose utilization. To generate CSH-deficient pregnancies, day 9 hatched blastocysts were infected with lentiviral particles expressing CSH-specific shRNA (RNAi) or scramble control shRNA (SC) and transferred to synchronized recipients. CSH RNAi generated two distinct phenotypes at 135 days of gestational age (dGA); pregnancies with IUGR (RNAi-IUGR) or with normal fetal weight (RNAi-NW). Fetal body, fetal liver and placental weights were reduced (P < 0.05) only in RNAi-IUGR pregnancies compared to SC. Umbilical artery plasma insulin and insulin-like growth factor 1 (IGF1) concentrations were decreased, whereas insulin receptor beta (INSR) concentration in fetal liver was increased (P < 0.05) in both RNAi phenotypes. The mRNA concentrations of IGF1, IGF2, IGF binding protein 2 (IGFBP2) and IGFBP3 were decreased (P < 0.05) in fetal livers from both RNAi phenotypes. Fetal liver glycogen concentration and glycogen synthase 1 (GYS1) concentration were increased (P < 0.05), whereas fetal liver phosphorylated-GYS (inactive GYS) concentration was reduced (P < 0.05) in both RNAi phenotypes. Lactate dehydrogenase B (LDHB) concentration was increased (P < 0.05) and IGF2 concentration was decreased (P < 0.05) in RNAi-IUGR fetal livers only. Our findings suggest that fetal liver glucose utilization is impacted by CSH RNAi, independent of IUGR, and is likely tied to enhanced fetal liver insulin sensitivity in both RNAi phenotypes. Determining the physiological ramifications of both phenotypes, may help to differentiate direct effect of CSH deficiency or its indirect effect through IUGR.
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Affiliation(s)
- Asghar Ali
- Colorado State University, Animal Reproduction and Biotechnology Lab, Fort Collins, CO, US
| | - Callie M. Swanepoel
- Colorado State University, Animal Reproduction and Biotechnology Lab, Fort Collins, CO, US
| | - Quinton A. Winger
- Colorado State University, Animal Reproduction and Biotechnology Lab, Fort Collins, CO, US
| | - Paul J. Rozance
- University of Colorado Anschutz Medical Campus, Perinatal Research Center, Aurora, CO, US
| | - Russell V. Anthony
- Colorado State University, Animal Reproduction and Biotechnology Lab, Fort Collins, CO, US
- Corresponding Author: 1683 Campus Delivery, 3107 Rampart Road, Colorado State University, Fort Collins, CO 80523-1683. Telephone: 970-491-2586; FAX: 970-491-3557;
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10
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Lin L, Zeng L, Liu A, Peng Y, Yuan D, Zhang S, Li Y, Chen J, Xiao W, Gong Z. l-Theanine regulates glucose, lipid, and protein metabolism via insulin and AMP-activated protein kinase signaling pathways. Food Funct 2020; 11:1798-1809. [PMID: 32057039 DOI: 10.1039/c9fo02451d] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
l-Theanine is an important component found in tea and has positive effects on nutrient absorption and transport. However, whether l-theanine can regulate glucose, lipid, and protein metabolism remains unknown. This study aims to investigate the effects of l-theanine on glucose, lipid, and protein metabolism in male Sprague-Dawley rats and characterize the underlying mechanisms. Compared to the control group, l-theanine increased the contents of hepatic and muscle glycogen, serum total protein (TP), and albumin (Alb), lowered the serum low-density lipoprotein cholesterol (LDL-C) level, decreased the activity of acetyl-CoA carboxylase (ACC), and enhanced carnitine palmitoyl transferase-1 (CPT-1) activity in the liver. Additionally, l-theanine upregulated the mRNA expression of phosphofructokinase (PFKL), CPT-1, insulin receptor (INSR), insulin receptor substrate (IRS), and liver kinase B1 (LKB1) and downregulated the mRNA expression of phosphoenolpyruvate carboxykinase 1 (PCK1), glucose-6-phosphatase catalytic subunit (G6PC), fatty acid synthase (FAS), and 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR). Moreover, l-theanine upregulated the expression of PFKL, glycogen synthase 2 (GYS2), ribosomal protein S6 (S6), INSR, IRS, and phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) proteins; downregulated the expression of FAS, sterol regulatory element binding protein-1c (SREBP-1c), and HMGCR proteins; enhanced the phosphorylation of the mammal target of rapamycin (mTOR), ribosomal protein S6 kinase (p70S6K), protein kinase B (AKT), and AMP-activated protein kinase (AMPK); and decreased the phosphorylation of glycogen synthase kinase 3β (GSK-3β) and ACC1. Furthermore, 100 mg kg-1l-theanine was more effective at eliciting these effects than 200 and 400 mg kg-1l-theanine. In conclusion, l-theanine can regulate glucose, lipid, and protein metabolism via insulin and AMPK and their downstream signaling pathways.
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Affiliation(s)
- Ling Lin
- Key Laboratory of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha, Hunan 410128, China.
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Tang B, Frasinyuk MS, Chikwana VM, Mahalingan KK, Morgan CA, Segvich DM, Bondarenko SP, Mrug GP, Wyrebek P, Watt DS, DePaoli-Roach AA, Roach PJ, Hurley TD. Discovery and Development of Small-Molecule Inhibitors of Glycogen Synthase. J Med Chem 2020; 63:3538-3551. [PMID: 32134266 DOI: 10.1021/acs.jmedchem.9b01851] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The overaccumulation of glycogen appears as a hallmark in various glycogen storage diseases (GSDs), including Pompe, Cori, Andersen, and Lafora disease. Accumulating evidence suggests that suppression of glycogen accumulation represents a potential therapeutic approach for treating these GSDs. Using a fluorescence polarization assay designed to screen for inhibitors of the key glycogen synthetic enzyme, glycogen synthase (GS), we identified a substituted imidazole, (rac)-2-methoxy-4-(1-(2-(1-methylpyrrolidin-2-yl)ethyl)-4-phenyl-1H-imidazol-5-yl)phenol (H23), as a first-in-class inhibitor for yeast GS 2 (yGsy2p). Data from X-ray crystallography at 2.85 Å, as well as kinetic data, revealed that H23 bound within the uridine diphosphate glucose binding pocket of yGsy2p. The high conservation of residues between human and yeast GS in direct contact with H23 informed the development of around 500 H23 analogs. These analogs produced a structure-activity relationship profile that led to the identification of a substituted pyrazole, 4-(4-(4-hydroxyphenyl)-3-(trifluoromethyl)-1H-pyrazol-5-yl)pyrogallol, with a 300-fold improved potency against human GS. These substituted pyrazoles possess a promising scaffold for drug development efforts targeting GS activity in GSDs associated with excess glycogen accumulation.
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Affiliation(s)
- Buyun Tang
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis 46202, Indiana, United States
| | - Mykhaylo S Frasinyuk
- V. P. Kukhar Institute of Bioorganic Chemistry and Petrochemistry, NAS of Ukraine, Kyiv 02094, Ukraine.,National University of Food Technologies, Kyiv 01601, Ukraine
| | - Vimbai M Chikwana
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis 46202, Indiana, United States
| | - Krishna K Mahalingan
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis 46202, Indiana, United States
| | - Cynthia A Morgan
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis 46202, Indiana, United States
| | - Dyann M Segvich
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis 46202, Indiana, United States
| | | | - Galyna P Mrug
- V. P. Kukhar Institute of Bioorganic Chemistry and Petrochemistry, NAS of Ukraine, Kyiv 02094, Ukraine.,National University of Food Technologies, Kyiv 01601, Ukraine
| | - Przemyslaw Wyrebek
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington 40506, Kentucky, United States.,Center for Pharmaceutical Research and Innovation, College of Pharmacy, University of Kentucky, Lexington 40536, Kentucky, United States
| | - David S Watt
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington 40506, Kentucky, United States.,Center for Pharmaceutical Research and Innovation, College of Pharmacy, University of Kentucky, Lexington 40536, Kentucky, United States.,Lucille Parker Markey Cancer Center, University of Kentucky, Lexington 40536, Kentucky, United States
| | - Anna A DePaoli-Roach
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis 46202, Indiana, United States
| | - Peter J Roach
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis 46202, Indiana, United States
| | - Thomas D Hurley
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis 46202, Indiana, United States
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12
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Karatug Kacar A. Indomethacin decreases insulin secretion by reducing KCa3.1 as a biomarker of pancreatic tumor and causes apoptotic cell death. J Biochem Mol Toxicol 2020; 34:e22488. [PMID: 32128977 DOI: 10.1002/jbt.22488] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 01/14/2020] [Accepted: 02/21/2020] [Indexed: 01/05/2023]
Abstract
Insulinomas originate from pancreatic β cells and it is the most widely known tumor. Indomethacin is a nonsteroidal anti-inflammatory drug, which is used for blocking the production of some natural substances that cause inflammation and decrease pain. In this study, I aimed to investigate the effects of indomethacin on rat insulinoma INS-1 cells. The relationship between cell death and insulin metabolism was determined with the administration of indomethacin. The cell viability by WST-1; the apoptosis and necrosis levels by ELISA kits; malondialdehyde levels by spectrophotometer; and beclin, intracellular insulin, insulin secretion, KCa3.1, insulin receptor (IR), glucose transporter type 2 (GLUT2), activating transcription factor 2 (ATF2), Elk1, c-Jun, Akt and phosphorylated ATF2, Elk1, c-Jun, Akt, intracellular betacellulin and betacellulin secretion levels by Western blot analysis investigated. The Ins1, Ins2, IR, GLUT2, ATF2, Elk1, c-Jun, Akt, and Betacellulin gene expression levels were determined by the real-time quantitative reverse transcription-polymerase chain reaction method. Apoptotic cell death was observed with the administration of indomethacin. The insulin secretion and Ins1, Ins2 gene expression levels decreased. The insulin receptor and GLUT2 levels increased, while KCa3.1 (KCNN4) levels decreased with the administration of indomethacin to insulinoma INS-1 cells. A decrease was observed in the total c-Jun, phosphorylated ATF2, Elk1, c-Jun, and Akt levels. Betacellulin secretion levels increased. In insulinoma INS-1 cells, apoptotic cell death occurred in the following manner: (i) indomethacin might decrease insulin secretion by reducing KCa3.1, (ii) might inactivate the JNK/ERK pathway with the inactivity of transcription factors.
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Affiliation(s)
- Ayse Karatug Kacar
- Department of Biology, Faculty of Science, Istanbul University, Istanbul, Turkey
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13
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Li C, Wei Q, Gu X, Chen Y, Chen X, Cao B, Ou R, Shang H. Decreased Glycogenolysis by miR-338-3p Promotes Regional Glycogen Accumulation Within the Spinal Cord of Amyotrophic Lateral Sclerosis Mice. Front Mol Neurosci 2019; 12:114. [PMID: 31133799 PMCID: PMC6514045 DOI: 10.3389/fnmol.2019.00114] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 04/18/2019] [Indexed: 02/05/2023] Open
Abstract
Metabolic dysfunction is a hallmark of age-related neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). But the crosstalk between metabolic alteration and disease progression in ALS is still largely unknown. Glycogen, a branched polymer of glucose residues, is universally recognized as the energy reserve of the central nervous system (CNS), where its aberrant accumulation instigates neurodegeneration. Glycogen was reported to be accumulated in both CNS and visceral organs of SOD1G93A mice, a well-known ALS model, and contributes to the pathological process of ALS. However, the accumulative patterns and mechanisms are not well elucidated. Here, we provide extensive evidence to demonstrate that glycogen accumulated in the lumbar spinal cord of ALS mice along with the disease progression, but not in the motor cortex. This regional accumulation of glycogen was caused by deteriorated glycogenolysis, which was triggered by decreased glycogen phosphorylase, brain form (PYGB). Moreover, miR-338-3p, an elevated miRNA in the spinal cord of SOD1G93A mice, directly targeted PYGB and was responsible for the decreased glycogenolysis and subsequent glycogen accumulation. Our work is helpful for better understanding of of of metabolic dysfunctions in ALS and provides novel targets for the therapeutic intervention in the future.
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Affiliation(s)
- Chunyu Li
- Department of Neurology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Qianqian Wei
- Department of Neurology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Xiaojing Gu
- Department of Neurology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Yongping Chen
- Department of Neurology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Xueping Chen
- Department of Neurology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Bei Cao
- Department of Neurology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Ruwei Ou
- Department of Neurology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Huifang Shang
- Department of Neurology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
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14
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Pederson BA. Structure and Regulation of Glycogen Synthase in the Brain. ADVANCES IN NEUROBIOLOGY 2019; 23:83-123. [PMID: 31667806 DOI: 10.1007/978-3-030-27480-1_3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Brain glycogen synthesis is a regulated, multi-step process that begins with glucose transport across the blood brain barrier and culminates with the actions of glycogen synthase and the glycogen branching enzyme to elongate glucose chains and introduce branch points in a growing glycogen molecule. This review focuses on the synthesis of glycogen in the brain, with an emphasis on glycogen synthase, but draws on salient studies in mammalian muscle and liver as well as baker's yeast, with the goal of providing a more comprehensive view of glycogen synthesis and highlighting potential areas for further study in the brain. In addition, deficiencies in the glycogen biosynthetic enzymes which lead to glycogen storage diseases in humans are discussed, highlighting effects on the brain and discussing findings in genetically modified animal models that recapitulate these diseases. Finally, implications of glycogen synthesis in neurodegenerative and other diseases that impact the brain are presented.
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15
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Ellingwood SS, Cheng A. Biochemical and clinical aspects of glycogen storage diseases. J Endocrinol 2018; 238:R131-R141. [PMID: 29875163 PMCID: PMC6050127 DOI: 10.1530/joe-18-0120] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 06/04/2018] [Indexed: 12/29/2022]
Abstract
The synthesis of glycogen represents a key pathway for the disposal of excess glucose while its degradation is crucial for providing energy during exercise and times of need. The importance of glycogen metabolism is also highlighted by human genetic disorders that are caused by mutations in the enzymes involved. In this review, we provide a basic summary on glycogen metabolism and some of the clinical aspects of the classical glycogen storage diseases. Disruptions in glycogen metabolism usually result in some level of dysfunction in the liver, muscle, heart, kidney and/or brain. Furthermore, the spectrum of symptoms observed is very broad, depending on the affected enzyme. Finally, we briefly discuss an aspect of glycogen metabolism related to the maintenance of its structure that seems to be gaining more recent attention. For example, in Lafora progressive myoclonus epilepsy, patients exhibit an accumulation of inclusion bodies in several tissues, containing glycogen with increased phosphorylation, longer chain lengths and irregular branch points. This abnormal structure is thought to make glycogen insoluble and resistant to degradation. Consequently, its accumulation becomes toxic to neurons, leading to cell death. Although the genes responsible have been identified, studies in the past two decades are only beginning to shed light into their molecular functions.
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Affiliation(s)
- Sara S Ellingwood
- Department of Biochemistry and Molecular GeneticsUniversity of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Alan Cheng
- Department of Biochemistry and Molecular GeneticsUniversity of Louisville School of Medicine, Louisville, Kentucky, USA
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16
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Shi M, Wang J, Xiao Y, Wang C, Qiu Q, Lao M, Yu Y, Li Z, Zhang H, Ye Y, Liang L, Yang X, Chen G, Xu H. Glycogen Metabolism and Rheumatoid Arthritis: The Role of Glycogen Synthase 1 in Regulation of Synovial Inflammation via Blocking AMP-Activated Protein Kinase Activation. Front Immunol 2018; 9:1714. [PMID: 30100905 PMCID: PMC6072843 DOI: 10.3389/fimmu.2018.01714] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 07/12/2018] [Indexed: 12/14/2022] Open
Abstract
Objective To investigate the role of glycogen metabolism in regulating rheumatoid fibroblast-like synoviocyte (FLS)-mediated synovial inflammation and its underlying mechanism. Methods FLSs were separated from synovial tissues (STs) obtained from rheumatoid arthritis (RA) patients. Glycogen content was determined by periodic acid Schiff staining. Protein expression was analyzed by Western blot or immunohistochemistry. Gene expression of cytokines and matrix metalloproteinases (MMPs) was evaluated by quantitative real-time PCR. FLS proliferation was detected by EdU incorporation. Migration and invasion were measured by Boyden chamber assay. Results Glycogen levels and glycogen synthase 1 (GYS1) expression were significantly increased in the ST and FLSs of RA patients. TNF-α or hypoxia induced GYS1 expression and glycogen synthesis in RA FLSs. GYS1 knockdown by shRNA decreased the expression of IL-1β, IL-6, CCL-2, MMP-1, and MMP-9 and proliferation and migration by increasing AMP-activated protein kinase (AMPK) activity in RA FLS. AMPK inhibitor or knockdown AMPK could reverse the inhibitory effect of GYS1 knockdown on the inflammatory response in RA FLSs; however, an AMPK agonist blocked RA FLS activity. We further determined that hypoxia-inducible factor-1α mediates TNF-α- or hypoxia-induced GYS1 expression and glycogen levels. Local joint depletion of GYS1 or intraperitoneal administration with an AMPK agonist ameliorated the severity of arthritis in rats with collagen-induced arthritis. Conclusion Our data demonstrate that GYS1-mediated glycogen accumulation contributes to FLS-mediated synovial inflammation in RA by blocking AMPK activation. In our knowledge, this is a first study linking glycogen metabolism to chronic inflammation. Inhibition of GYS1 might be a novel therapeutic strategy for chronic inflammatory arthritis, including RA.
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Affiliation(s)
- Maohua Shi
- Department of Rheumatology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China.,Department of Rheumatology, The First People's Hospital of Foshan, Foshan, Guangdong, China
| | - Jingnan Wang
- Department of Rheumatology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Youjun Xiao
- Department of Rheumatology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Cuicui Wang
- Department of Rheumatology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Qian Qiu
- Department of Rheumatology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Minxi Lao
- Department of Rheumatology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Yangtao Yu
- Department of Rheumatology, The First People's Hospital of Foshan, Foshan, Guangdong, China
| | - Zhifeng Li
- Department of Rheumatology, The First People's Hospital of Foshan, Foshan, Guangdong, China
| | - Hongwei Zhang
- Department of Rheumatology, The First People's Hospital of Foshan, Foshan, Guangdong, China
| | - Yujin Ye
- Department of Rheumatology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Liuqin Liang
- Department of Rheumatology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Xiuyan Yang
- Department of Rheumatology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Guoqiang Chen
- Department of Rheumatology, The First People's Hospital of Foshan, Foshan, Guangdong, China
| | - Hanshi Xu
- Department of Rheumatology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
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17
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Li R, Zhu LN, Ren LQ, Weng JY, Sun JS. Molecular cloning and characterization of glycogen synthase in Eriocheir sinensis. Comp Biochem Physiol B Biochem Mol Biol 2017; 214:47-56. [DOI: 10.1016/j.cbpb.2017.09.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 08/27/2017] [Accepted: 09/19/2017] [Indexed: 01/26/2023]
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18
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Difference in glycogen metabolism (glycogen synthesis and glycolysis) between normal and dysplastic/malignant oral epithelium. Arch Oral Biol 2017; 83:340-347. [PMID: 28892665 DOI: 10.1016/j.archoralbio.2017.08.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 08/23/2017] [Accepted: 08/27/2017] [Indexed: 11/23/2022]
Abstract
BACKGROUND The purpose of this study was to investigate a difference in glycogen metabolism (glycogen synthesis and glycolysis) between the iodine stained (normal non-keartinized) and the unstained (dysplasctic/malignant) oral epithelium. METHODS Twenty-one frozen tissue samples of iodine-stained and unstained mucosal tissue were obtained from 21 OSCC patients. Serial frozen sections were cut and examined with the hematoxylin-eosin and periodic acid-Schiff methods and immunohistochemical (IHC) staining for Ki67, P53, molecules associated with glycogenesis (i.e., glycogen synthase (GS) and phospho-glycogen synthase (PGS)), and molecules associated with glycogenolysis (i.e., glycogen phosphorylase isoenzyme BB (GPBB) examine the glycogen metabolism in OSCC. Additionally, in vitro study, the expression levels of GS and GPBB in the cultured cells were analyzed by immunofluorescent staining, Western blot analysis, and the real-time quantitative polymerase chain reaction (PCR). RESULTS There was no significant difference in GS and PGS immunoactivity between iodine stained and unstained area. On the other hand, significantly greater GPBB immunoreactivity was observed in the basal and parabasal layers of iodine-unstained epithelium, where higher positivity for p53 and Ki67 was also showed. Additionally, western blot analysis, immunofluorescent staining, and real-time quantitative PCR revealed that the oral squamous cancer cells exhibited greater expression of GPBB than normal epithelial cells. CONCLUSIONS The results of this study showed that GPBB expression, which resulted in up-regulation of glycogenolysis, is enhanced in oral dysplastic/malignant epithelium compared with non-keartinized normal epithelium, in spite of the fact that glycogenesis continues in both of them. Premalignant and malignant epithelial cells consume greater quantities of energy due to their increased proliferation, and hence, exhaust their glycogen stores, which resulting in negative stain reaction with iodine solution.
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19
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Nakano K, Takeshita S, Kawasaki N, Miyanaga W, Okamatsu Y, Dohi M, Nakagawa T. AJS1669, a novel small-molecule muscle glycogen synthase activator, improves glucose metabolism and reduces body fat mass in mice. Int J Mol Med 2017; 39:841-850. [PMID: 28290602 PMCID: PMC5360432 DOI: 10.3892/ijmm.2017.2909] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 02/16/2017] [Indexed: 12/24/2022] Open
Abstract
Impaired glycogen synthesis and turnover are common in insulin resistance and type 2 diabetes. As glycogen synthase (GS) is a key enzyme involved in the synthetic process, it presents a promising therapeutic target for the treatment of type 2 diabetes. In the present study, we identified a novel, potent and orally available GS activator AJS1669 {sodium 2-[[5-[[4-(4,5-difluoro-2-methylsulfanyl-phenyl) phenoxy] methyl]furan-2-carbonyl]-(2-furylmethyl)amino] acetate}. In vitro, we performed a glycogen synthase 1 (GYS1) activation assay for screening GS activators and identified that the activity of AJS1669 was further potentiated in the presence of glucose-6-phosphate (G6P). In vivo, we used ob/ob mice to evaluate the novel anti-diabetic effects of AJS1669 by measuring basal blood glucose levels, glucose tolerance and body fat mass index. Repeated administration of AJS1669 over 4 weeks reduced blood glucose and hemoglobin A1c (HbA1c) levels in ob/ob mice. AJS1669 also improved glucose tolerance in a dose-dependent manner, and decreased body fat mass. The mRNA levels of genes involved in mitochondrial fatty acid oxidation and mitochondrial biogenesis were elevated in skeletal muscle tissue following AJS1669 treatment. Hepatic tissue of treated mice also exhibited elevated expression of genes associated with fatty acid oxidation. In contrast to ob/ob mice, in C57Bl/6 mice AJS1669 administration did not alter body weight or reduce glucose levels. These results demonstrate that pharmacological agents that activate GYS1, the main GS subtype found in skeletal muscle, have potential for use as novel treatments for diabetes that improve glucose metabolism in skeletal muscle.
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Affiliation(s)
- Kazuhiro Nakano
- Innovation Promotion Department, Research Institute, EA Pharma Co., Ltd., Kawasaki, Kanagawa 210-868, Japan
| | - Sen Takeshita
- Innovation Promotion Department, Research Institute, EA Pharma Co., Ltd., Kawasaki, Kanagawa 210-868, Japan
| | - Noriko Kawasaki
- Nutrition and Health Science Group Frontier Research Laboratories, Institute for Innovation, Ajinomoto Co., Inc., Kawasaki, Kanagawa 210-8681, Japan
| | - Wataru Miyanaga
- Business Development Department, EA Pharma Co., Ltd., Chuo-ku, Tokyo 104-0042, Japan
| | - Yoriko Okamatsu
- Novel Projects Research Group, Institute for Innovation, Ajinomoto Co., Inc., Kawasaki, Kanagawa 210-8681, Japan
| | - Mizuki Dohi
- Innovation Promotion Department, Research Institute, EA Pharma Co., Ltd., Kawasaki, Kanagawa 210-868, Japan
| | - Tadakiyo Nakagawa
- Intellectual Property Department, EA Pharma Co., Ltd., Chuo-ku, Tokyo 104-0042, Japan
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20
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Zhang L, Wang H, Chen J, Shen Q, Wang S, Xu H, Tang B. Glycogen Phosphorylase and Glycogen Synthase: Gene Cloning and Expression Analysis Reveal Their Role in Trehalose Metabolism in the Brown Planthopper, Nilaparvata lugens Stål (Hemiptera: Delphacidae). JOURNAL OF INSECT SCIENCE (ONLINE) 2017; 17:3075279. [PMID: 28365765 PMCID: PMC5469382 DOI: 10.1093/jisesa/iex015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Indexed: 06/07/2023]
Abstract
RNA interference has been used to study insects' gene function and regulation. Glycogen synthase (GS) and glycogen phosphorylase (GP) are two key enzymes in carbohydrates' conversion in insects. Glycogen content and GP and GS gene expression in several tissues and developmental stages of the Brown planthopper Nilaparvata lugens Stål (Hemiptera: Delphacidae) were analyzed in the present study, using quantitative reverse-transcription polymerase chain reaction to determine their response to double-stranded trehalases (dsTREs), trehalose-6-phosphate synthases (dsTPSs), and validamycin injection. The highest expression of both genes was detected in the wing bud, followed by leg and head tissues, and different expression patterns were shown across the developmental stages analyzed. Glycogen content significantly decreased 48 and 72 h after dsTPSs injection and 48 h after dsTREs injection. GP expression increased 48 h after dsTREs and dsTPSs injection and significantly decreased 72 h after dsTPSs, dsTRE1-1, and dsTRE1-2 injection. GS expression significantly decreased 48 h after dsTPS2 and dsTRE2 injection and 72 h after dsTRE1-1 and dsTRE1-2 injection. GP and GS expression and glycogen content significantly decreased 48 h after validamycin injection. The GP activity significantly decreased 48 h after validamycin injection, while GS activities of dsTPS1 and dsTRE2 injection groups were significantly higher than that of double-stranded GFP (dsGFP) 48 h after injection, respectively. Thus, glycogen is synthesized, released, and degraded across several insect tissues according to the need to maintain stable trehalose levels.
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Affiliation(s)
- Lu Zhang
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang 310036, China (; ; ; ; )
| | - Huijuan Wang
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang 310036, China (; ; ; ; )
| | - Jianyi Chen
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang 310036, China (; ; ; ; )
| | - Qida Shen
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang 310036, China (; ; ; ; )
| | - Shigui Wang
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang 310036, China (; ; ; ; )
| | - Hongxing Xu
- Institute of Plant Protection and Microbiology, Zhejiang Academy of Agriculture Sciences, Hangzhou 310021, China (xu )
| | - Bin Tang
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang 310036, China (; ; ; ; )
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21
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Mahalingan KK, Baskaran S, DePaoli-Roach AA, Roach PJ, Hurley TD. Redox Switch for the Inhibited State of Yeast Glycogen Synthase Mimics Regulation by Phosphorylation. Biochemistry 2016; 56:179-188. [PMID: 27935293 DOI: 10.1021/acs.biochem.6b00884] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Glycogen synthase (GS) is the rate limiting enzyme in the synthesis of glycogen. Eukaryotic GS is negatively regulated by covalent phosphorylation and allosterically activated by glucose-6-phosphate (G-6-P). To gain structural insights into the inhibited state of the enzyme, we solved the crystal structure of yGsy2-R589A/R592A to a resolution of 3.3 Å. The double mutant has an activity ratio similar to the phosphorylated enzyme and also retains the ability to be activated by G-6-P. When compared to the 2.88 Å structure of the wild-type G-6-P activated enzyme, the crystal structure of the low-activity mutant showed that the N-terminal domain of the inhibited state is tightly held against the dimer-related interface thereby hindering acceptor access to the catalytic cleft. On the basis of these two structural observations, we developed a reversible redox regulatory feature in yeast GS by substituting cysteine residues for two highly conserved arginine residues. When oxidized, the cysteine mutant enzyme exhibits activity levels similar to the phosphorylated enzyme but cannot be activated by G-6-P. Upon reduction, the cysteine mutant enzyme regains normal activity levels and regulatory response to G-6-P activation.
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Affiliation(s)
- Krishna K Mahalingan
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine , Indianapolis, Indiana 46202, United States
| | - Sulochanadevi Baskaran
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine , Indianapolis, Indiana 46202, United States
| | - Anna A DePaoli-Roach
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine , Indianapolis, Indiana 46202, United States
| | - Peter J Roach
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine , Indianapolis, Indiana 46202, United States
| | - Thomas D Hurley
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine , Indianapolis, Indiana 46202, United States
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22
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Varis J, Haverinen J, Vornanen M. Lowering Temperature is the Trigger for Glycogen Build-Up and Winter Fasting in Crucian Carp (Carassius carassius). Zoolog Sci 2016; 33:83-91. [PMID: 26853873 DOI: 10.2108/zs150072] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Seasonal changes in physiology of vertebrate animals are triggered by environmental cues including temperature, day-length and oxygen availability. Crucian carp (Carassius carassius) tolerate prolonged anoxia in winter by using several physiological adaptations that are seasonally activated. This study examines which environmental cues are required to trigger physiological adjustments for winter dormancy in crucian carp. To this end, crucian carp were exposed to changing environmental factors under laboratory conditions: effects of declining water temperature, shortening day-length and reduced oxygen availability, separately and in different combinations, were examined on glycogen content and enzyme activities involved in feeding (alkaline phosphatase, AP) and glycogen metabolism (glycogen synthase, GyS; glycogen phosphorylase, GP). Lowering temperature induced a fall in activity of AP and a rise in glycogen content and rate of glycogen synthesis. Relative mass of the liver, and glycogen concentration of liver, muscle and brain increased with lowering temperature. Similarly activity of GyS in muscle and expression of GyS transcripts in brain were up-regulated by lowering temperature. Shortened day-length and oxygen availability had practically no effects on measured variables. We conclude that lowering temperature is the main trigger in preparation for winter anoxia in crucian carp.
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Affiliation(s)
- Joonas Varis
- Department of Biology, University of Eastern Finland, Yliopistokatu 7, 80101 Joensuu, Natura-building, Finland
| | - Jaakko Haverinen
- Department of Biology, University of Eastern Finland, Yliopistokatu 7, 80101 Joensuu, Natura-building, Finland
| | - Matti Vornanen
- Department of Biology, University of Eastern Finland, Yliopistokatu 7, 80101 Joensuu, Natura-building, Finland
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23
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Bhanot H, Reddy MM, Nonami A, Weisberg EL, Bonal D, Kirschmeier PT, Salgia S, Podar K, Galinsky I, Chowdary TK, Neuberg D, Tonon G, Stone RM, Asara J, Griffin JD, Sattler M. Pathological glycogenesis through glycogen synthase 1 and suppression of excessive AMP kinase activity in myeloid leukemia cells. Leukemia 2015; 29:1555-1563. [PMID: 25703587 PMCID: PMC4497855 DOI: 10.1038/leu.2015.46] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 11/17/2014] [Accepted: 12/18/2014] [Indexed: 12/20/2022]
Abstract
The rapid proliferation of myeloid leukemia cells is highly dependent on increased glucose metabolism. Through an unbiased metabolomics analysis of leukemia cells, we found that the glycogenic precursor UDP-D-glucose is pervasively upregulated, despite low glycogen levels. Targeting the rate-limiting glycogen synthase 1 (GYS1) not only decreased glycolytic flux but also increased activation of the glycogen-responsive AMPK (AMP kinase), leading to significant growth suppression. Further, genetic and pharmacological hyper-activation of AMPK was sufficient to induce the changes observed with GYS1 targeting. Cancer genomics data also indicate that elevated levels of the glycogenic enzymes GYS1/2 or GBE1 (glycogen branching enzyme 1) are associated with poor survival in AML. These results suggest a novel mechanism whereby leukemic cells sustain aberrant proliferation by suppressing excess AMPK activity through elevated glycogenic flux and provide a therapeutic entry point for targeting leukemia cell metabolism.
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Affiliation(s)
- Haymanti Bhanot
- Department of Medical Oncology, Boston, MA, 02215, USA.,Department of Medicine, Harvard Medical School, Boston, MA 02215, USA
| | - Mamatha M Reddy
- Department of Medical Oncology, Boston, MA, 02215, USA.,Department of Medicine, Harvard Medical School, Boston, MA 02215, USA
| | - Atsushi Nonami
- Department of Medical Oncology, Boston, MA, 02215, USA.,Department of Medicine, Harvard Medical School, Boston, MA 02215, USA
| | - Ellen L Weisberg
- Department of Medical Oncology, Boston, MA, 02215, USA.,Department of Medicine, Harvard Medical School, Boston, MA 02215, USA
| | - Dennis Bonal
- Center for Biomedical Imaging in Oncology (CBIO), Lurie Family Imaging Center (LFIC), Boston, MA, 02215, USA
| | - Paul T Kirschmeier
- Center for Biomedical Imaging in Oncology (CBIO), Lurie Family Imaging Center (LFIC), Boston, MA, 02215, USA
| | | | - Klaus Podar
- National Center for Tumor Diseases (NCT), Heidelberg, Germany.,University of Heidelberg, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | | | - Tirumala K Chowdary
- School of Biological Sciences, National Institute of Science Education & Research, Bhubaneswar, India
| | - Donna Neuberg
- Department of Biostatistics and Computational Biology Dana-Farber Cancer Institute, Boston, MA, 02215, USA
| | | | - Richard M Stone
- Department of Medical Oncology, Boston, MA, 02215, USA.,Department of Medicine, Harvard Medical School, Boston, MA 02215, USA
| | - John Asara
- Department of Medicine, Harvard Medical School, Boston, MA 02215, USA.,Division of Signal Transduction/Mass Spectrometry Core, Beth Israel Deaconess Medical Center, Boston, MA02215, USA
| | - James D Griffin
- Department of Medical Oncology, Boston, MA, 02215, USA.,Department of Medicine, Harvard Medical School, Boston, MA 02215, USA
| | - Martin Sattler
- Department of Medical Oncology, Boston, MA, 02215, USA.,Department of Medicine, Harvard Medical School, Boston, MA 02215, USA
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Insights into Transcriptional Regulation of Hepatic Glucose Production. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 318:203-53. [DOI: 10.1016/bs.ircmb.2015.05.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Yu Y, Chai J. The function of miRNAs and their potential as therapeutic targets in burn-induced insulin resistance (review). Int J Mol Med 2014; 35:305-10. [PMID: 25484249 DOI: 10.3892/ijmm.2014.2023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2014] [Accepted: 12/03/2014] [Indexed: 11/06/2022] Open
Abstract
Burns are common accidental injuries. The main clinical manifestations of severe burn injury are insulin resistance and high metabolism. Insulin resistance results in hyperglycemia, which may lead to skeletal muscle wasting and suspended wound healing. It also elevates the risk of infection and sepsis. Studies have indicated that insulin receptor (IR) and insulin receptor substrate 1 (IRS1) are essential factors involved in the regulation of blood glucose levels. Moreover, the suppression of the IR/IRS1 signaling pathway results in insulin resistance. Recent studies have also indicated that miRNAs, which are small non-coding RNAs consisting of 20-23 nucleotides, target the 3'-untranslated region (3'-UTR) of IRS1 mRNA and attenuate protein translation. miRNAs also play an important role in the development of type II diabetes (T2D) and obesity-induced insulin resistance. In the present review, we discuss the involvement of miRNAs in burn-induced insulin resistance through the targeting of the IR/IRS1 signaling pathway. We also discuss the possibility of miRNAs a novel therapeutic target in insulin resistance in burn patients.
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Affiliation(s)
- Yonghui Yu
- Department of Burn and Plastic Surgery, The First Affiliated Hospital of PLA General Hospital, Beijing 100048, P.R. China
| | - Jiake Chai
- Department of Burn and Plastic Surgery, The First Affiliated Hospital of PLA General Hospital, Beijing 100048, P.R. China
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Parallel Evolution of the Glycogen Synthase 1 (Muscle) Gene Gys1 Between Old World and New World Fruit Bats (Order: Chiroptera). Biochem Genet 2014; 52:443-58. [DOI: 10.1007/s10528-014-9659-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 06/06/2014] [Indexed: 01/09/2023]
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The Glycogen Synthase 2 Gene (Gys2) Displays Parallel Evolution Between Old World and New World Fruit Bats. J Mol Evol 2013; 78:66-74. [DOI: 10.1007/s00239-013-9600-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 11/12/2013] [Indexed: 01/02/2023]
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Villarroel-Espíndola F, Maldonado R, Mancilla H, vander Stelt K, Acuña AI, Covarrubias A, López C, Angulo C, Castro MA, Slebe JC, Durán J, García-Rocha M, Guinovart JJ, Concha II. Muscle glycogen synthase isoform is responsible for testicular glycogen synthesis: glycogen overproduction induces apoptosis in male germ cells. J Cell Biochem 2013; 114:1653-64. [PMID: 23386391 DOI: 10.1002/jcb.24507] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2012] [Accepted: 01/22/2013] [Indexed: 01/03/2023]
Abstract
Glycogen is the main source of glucose for many biological events. However, this molecule may have other functions, including those that have deleterious effects on cells. The rate-limiting enzyme in glycogen synthesis is glycogen synthase (GS). It is encoded by two genes, GYS1, expressed in muscle (muscle glycogen synthase, MGS) and other tissues, and GYS2, primarily expressed in liver (liver glycogen synthase, LGS). Expression of GS and its activity have been widely studied in many tissues. To date, it is not clear which GS isoform is responsible for glycogen synthesis and the role of glycogen in testis. Using RT-PCR, Western blot and immunofluorescence, we have detected expression of MGS but not LGS in mice testis during development. We have also evaluated GS activity and glycogen storage at different days after birth and we show that both GS activity and levels of glycogen are higher during the first days of development. Using RT-PCR, we have also shown that malin and laforin are expressed in testis, key enzymes for regulation of GS activity. These proteins form an active complex that regulates MGS by poly-ubiquitination in both Sertoli cell and male germ cell lines. In addition, PTG overexpression in male germ cell line triggered apoptosis by caspase3 activation, proposing a proapoptotic role of glycogen in testis. These findings suggest that GS activity and glycogen synthesis in testis could be regulated and a disruption of this process may be responsible for the apoptosis and degeneration of seminiferous tubules and possible cause of infertility.
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Qian Y, Bolin DR, Conde-Knape K, Gillespie P, Hayden S, Huang KS, Liu M, Olivier AR, Ren Y, Sergi J, Xiang Q, Yi L, Yun W, Zhang X. N-substituted sultam carboxylic acids as novel glycogen synthase activators. MEDCHEMCOMM 2013. [DOI: 10.1039/c3md00053b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
We discovered a novel class of N-substituted sultam carboxylic acids as potent glycogen synthase activators with cellular activity and oral bioavailability.
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Affiliation(s)
- Yimin Qian
- Discovery Chemistry
- Hoffmann-La Roche
- Nutley
- USA
| | | | | | | | | | | | - Mei Liu
- Pharmacokinetics and Drug Metabolism
- Hoffmann-La Roche
- Nutley
- USA
| | | | - Yonglin Ren
- Metabolic and Vascular Diseases
- Hoffmann-La Roche
- Nutley
- USA
| | - Joseph Sergi
- Metabolic and Vascular Diseases
- Hoffmann-La Roche
- Nutley
- USA
| | - Qing Xiang
- Discovery Technologies
- Hoffmann-La Roche
- Nutley
- USA
| | - Lin Yi
- Discovery Chemistry
- Hoffmann-La Roche
- Nutley
- USA
| | - Weiya Yun
- Discovery Chemistry
- Hoffmann-La Roche
- Nutley
- USA
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Tang B, Xu Q, Zou Q, Fang Q, Wang S, Ye G. Sequencing and characterization of glycogen synthase and glycogen phosphorylase genes from Spodoptera exigua and analysis of their function in starvation and excessive sugar intake. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2012; 80:42-62. [PMID: 22550018 DOI: 10.1002/arch.21027] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Glycogen and trehalose are important energy source and key regulation factors in the development of many organisms' pass through energy metabolism, including bacteria, fungi, and insects. To study glycogen metabolism pathway in Spodoptera exigua, first cDNAs for glycogen synthase (SpoexGS) and glycogen phosphorylase (SpoexGP) were cloned from S. exigua. SpoexGS cDNA contains an open reading frame of 2,010 nucleotides encoding a protein of 669 amino acids with a predicted molecular mass of 76.19 kDa and a pI of 5.84. SpoexGP contains an open reading frame of 2,946 nucleotides, which encodes a protein of 841 amino acids with a predicted molecular mass of approximately 96.63 kDa and a pI of 6.03. Second, Northern blotting revealed that SpoexGS and SpoexGP mRNAs were expressed in brain, fat body, mid-gut, Malpighian tubules, spermary, and tracheae of S. exigua. Expression patterns for SpoexGS and SpoexGP mRNAs were similar in fat body, but differed in whole body at different developmental stages. The last, under starvation conditions, SpoexGS and SpoexGP transcript expression rapidly decreased with increasing starvation time. When the starvation stress was removed, SpoexGS and SpoexGP mRNA levels were lower in the groups starved for 6 and 12 h than in the 24-h starvation and control groups. Treatment with excessive sugar intake led to higher levels of SpoexGS and SpoexGP transcripts after 12 h compared to the control group. These findings provide new data on the tissue distribution, expression patterns, and potential function of glycogen synthase and glycogen phosphorylase proteins.
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Affiliation(s)
- Bin Tang
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, Zhejiang, China
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Abstract
Glycogen is a branched polymer of glucose that acts as a store of energy in times of nutritional sufficiency for utilization in times of need. Its metabolism has been the subject of extensive investigation and much is known about its regulation by hormones such as insulin, glucagon and adrenaline (epinephrine). There has been debate over the relative importance of allosteric compared with covalent control of the key biosynthetic enzyme, glycogen synthase, as well as the relative importance of glucose entry into cells compared with glycogen synthase regulation in determining glycogen accumulation. Significant new developments in eukaryotic glycogen metabolism over the last decade or so include: (i) three-dimensional structures of the biosynthetic enzymes glycogenin and glycogen synthase, with associated implications for mechanism and control; (ii) analyses of several genetically engineered mice with altered glycogen metabolism that shed light on the mechanism of control; (iii) greater appreciation of the spatial aspects of glycogen metabolism, including more focus on the lysosomal degradation of glycogen; and (iv) glycogen phosphorylation and advances in the study of Lafora disease, which is emerging as a glycogen storage disease.
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Wang L, Xiong Y, Zuo B, Lei M, Ren Z, Xu D. Molecular and functional characterization of glycogen synthase in the porcine satellite cells under insulin treatment. Mol Cell Biochem 2011; 360:169-80. [PMID: 21931959 DOI: 10.1007/s11010-011-1054-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Accepted: 09/08/2011] [Indexed: 12/24/2022]
Abstract
Glycogen synthase (GS) catalyzes the key step of glycogen synthesis and plays an important role in glycogen metabolism in liver and muscle. In this study, we cloned the cDNA and promoter sequences of porcine glycogen synthesis genes (GYS1 and GYS2). Expression analysis revealed that porcine GYS1 was highly expressed in the skeletal muscle and heart. GYS2 was expressed specifically in liver and subcutaneous adipose tissue. The expression level of GYS1 was up-regulated from proliferation to differentiation in the porcine satellite cells, and insulin did not significantly affect the transcription of GYS1. Insulin stimulated 72-h-differentiated satellite cells as indicated by decrease in phosphorylation of GS, but did not affect GYS1 transcription and total GS protein level, suggesting that the effect of insulin is primarily mediated via posttranscriptional control rather than regulated at the transcriptional level. Four single-nucleotide polymorphisms (SNPs) were detected in the promoter and cDNA sequences of porcine GYS1. Association analyses revealed that the GYS1 Hin6I and MvaI polymorphisms both had significant associations (P < 0.05) with pH of M. longissimus dorsi (pHLD), M. biceps femoris (pHBF) and M. semipinalis capitis (pHSC) at 45 min postmortem. These results provide useful information for further investigation on the function of glycogen synthase in porcine skeletal muscle.
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Affiliation(s)
- Linjie Wang
- Key Laboratory of Swine Genetics and Breeding, Ministry of Agriculture, College of Animal Science, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
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34
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Kruszynska YT, Ciaraldi TP, Henry RR. Regulation of Glucose Metabolism in Skeletal Muscle. Compr Physiol 2011. [DOI: 10.1002/cphy.cp070218] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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35
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Molecular characterization of glycogen synthase 1 and its tissue expression profile with type II hexokinase and muscle-type phosphofructokinase in horses. Mol Biol Rep 2010; 38:461-9. [DOI: 10.1007/s11033-010-0129-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Accepted: 03/23/2010] [Indexed: 01/07/2023]
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Schoser B, Bruno C, Schneider HC, Shin YS, Podskarbi T, Goldfarb L, Müller-Felber W, Müller-Höcker J. Unclassified polysaccharidosis of the heart and skeletal muscle in siblings. Mol Genet Metab 2008; 95:52-8. [PMID: 18691923 PMCID: PMC2583439 DOI: 10.1016/j.ymgme.2008.07.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Accepted: 07/03/2008] [Indexed: 11/24/2022]
Abstract
We describe a 15-year-old boy and his 19-year-old sister with progressive dilated cardiomyopathy and mild non-progressive proximal lower limb myopathy, secondary to the accumulation of amylopectin-like fibrillar glycogen, (polyglucosan) bodies, in heart and skeletal muscle. Evidence of idiopathic amylopectinosis or polysaccharidosis was demonstrated in heart and skeletal muscle tissue by histology, electron microscopy, biochemical, and genetic analysis. In both siblings the heart muscle stored PAS-positive, proteinase-k resistant and partly diastase resistant granulo-filamentous material, simulating polyglucosan bodies. Glycogen branching enzyme activity, and phosphofructokinase enzyme activity, measured in skeletal muscle tissue and explanted heart tissue were all within the normal limits, however glycogen content was elevated. Furthermore, GBE1, PRKAG2, desmin, alphabeta-crystallin, ZASP, myotilin, and LAMP-2 gene sequencing revealed no mutation, excluding e.g. glycogen storage disease type 4 and desmin-related myofibrillar cardiomyopathies. In both patients the diagnosis of an idiopathic polysaccharidosis with progressive dilated cardiomyopathy was made, requiring heart transplantation at age 13 and 14, respectively. Both patients belong to an autosomal recessive group of biochemically and genetically unclassified severe vacuolar glycogen storage disease of the heart and skeletal muscle. Up to now unidentified glycogen synthesis or glycogen degradation pathways are supposed to contribute to this idiopathic glycogen storage disease.
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Affiliation(s)
- Benedikt Schoser
- Friedrich Baur Institute, Department of Neurology, Ludwig Maximilians University of Munich, Munich, Germany.
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Engl J, Laimer M, Niederwanger A, Kranebitter M, Starzinger M, Pedrini MT, Fleischhacker WW, Patsch JR, Ebenbichler CF. Olanzapine impairs glycogen synthesis and insulin signaling in L6 skeletal muscle cells. Mol Psychiatry 2005; 10:1089-96. [PMID: 16130009 DOI: 10.1038/sj.mp.4001729] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Second-generation antipsychotic agents (SGAs) are increasingly replacing first-generation antipsychotic agents due to their superior activity against the negative symptoms of schizophrenia, decreased extrapyramidal symptoms and better tolerability. However, some SGAs are associated with adverse metabolic effects as significant weight gain, lipid disorders and diabetes mellitus. The pathogenesis of SGA-induced disturbances of glucose homeostasis is unclear. In vivo studies suggest a direct influence of SGAs on peripheral insulin resistance. To this end, we analyzed whether olanzapine might alter glycogen synthesis and the insulin-signaling cascade in L6 myotubes. Glycogen content was diminished in a dose- and time-dependent manner. Within the insulin-signaling cascade IRS-1 tyrosine phosphorylation was induced several fold by insulin and was diminished by preincubation with olanzapine. IRS-1-associated PI3K activity was stimulated by insulin three-fold in L6 myotubes. Olanzapine inhibited insulin-stimulated IRS-1-associated PI3K activity in a dose-dependent manner. Protein mass of AKT, GSK-3 and GS was unaltered, whereas phosphorylation of AKT and GSK-3 was diminished, and pGS was increased. Finally, we compared olanzapine with amisulpride, an SGA clinically not associated with the induction of diabetes mellitus. Glycogen content was diminished in olanzapine-preincubated L6 cells, whereas this effect was not observed under the amisulpride conditions. We conclude that olanzapine impairs glycogen synthesis via inhibition of the classical insulin-signaling cascade and that this inhibitory effect may lead to the induction of insulin resistance in olanzapine-treated patients.
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Affiliation(s)
- J Engl
- Clinical Department of Internal Medicine, Clinical Division of General Internal Medicine, Innsbruck, Austria
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Zuo B, Xiong YZ, Deng CY, Su YH, Wang J, Lei MG, Li FE, Jiang SW, Zheng R. Polymorphism, linkage mapping and expression pattern of the porcine skeletal muscle glycogen synthase (GYS1) gene. Anim Genet 2005; 36:254-7. [PMID: 15932409 DOI: 10.1111/j.1365-2052.2005.01286.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The glycogen synthase gene (GYS1), which encodes the rate-limiting enzyme for glycogen synthesis of skeletal muscle, is a promising candidate gene for traits related to skeletal muscle in pigs. In this study, a G/A single nucleotide polymorphism in GYS1 intron 7 detected as a FokI PCR-restriction fragment length polymorphism (PCR-RFLP) showed allele frequency differences among five Chinese indigenous pig breeds and three western commercial pig breeds. Linkage analysis assigned the gene GYS1 to marker interval SW1302-SW1473 on SSC6 in a three-generation Meishan X Large White reference family. The results of association analysis and interval mapping suggested that the FokI PCR-RFLP polymorphism might be linked with the quantitative trait loci affecting carcass traits detected on SSC6 in the F2 intercross pedigree. The reverse transcriptase-polymerase chain reaction revealed that the porcine GYS1 gene was expressed in spleen, lung, liver, kidney, small intestine, skeletal muscle, heart and stomach, with the highest expression in skeletal muscle.
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Affiliation(s)
- B Zuo
- Key Laboratory of Swine Genetics and Breeding, Ministry of Agriculture, College of Animal Science and Veterinary Medicine, Huazhong Agriculture University, Wuhan 430070, China
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Ortmeyer HK, Adall Y, Marciani KR, Katsiaras A, Ryan AS, Bodkin NL, Hansen BC. Skeletal muscle glycogen synthase subcellular localization: effects of insulin and PPAR-α agonist (K-111) administration in rhesus monkeys. Am J Physiol Regul Integr Comp Physiol 2005; 288:R1509-17. [PMID: 15761185 DOI: 10.1152/ajpregu.00692.2004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Insulin covalently and allosterically regulates glycogen synthase (GS) and may also cause the translocation of GS from glycogen-poor to glycogen-rich locations. We examined the possible role of subcellular localization of GS and glycogen in insulin activation of GS in skeletal muscle of six obese monkeys and determined whether 1) insulin stimulation during a hyperinsulinemic euglycemic clamp and/or peroxisome proliferator-activated receptor (PPAR)-α agonist treatment (K-111, 3 mg·kg−1·day−1; Kowa) induced translocation of GS and 2) translocation of GS was associated with insulin activation of GS. GS and glycogen were present in all fractions obtained by differential centrifugation, except for the cytosolic fraction, under both basal and insulin-stimulated conditions. We found no evidence for translocation of GS by insulin. GS total (GST) activity was strongly associated with glycogen content ( r = 0.70, P < 0.001). Six weeks of treatment with K-111 increased GST activity in all fractions, except the cytosolic fraction, and mean GST activity, GS independent activity, and glycogen content were significantly higher in the insulin-stimulated samples compared with basal samples, effects not seen with vehicle. The increase in GST activity was strongly related to the increase in glycogen content during the hyperinsulinemic euglycemic clamp after K-111 administration ( r = 0.74, P < 0.001). Neither GS protein expression nor GS gene expression was affected by insulin or by K-111 treatment. We conclude that 1) in vivo insulin does not cause translocation of GS from a glycogen-poor to a glycogen-rich location in primate skeletal muscle and 2) the mechanism of action of K-111 to improve insulin sensitivity includes an increase in GST activity without an increase in GS gene or protein expression.
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Affiliation(s)
- Heidi K Ortmeyer
- Obesity and Diabetes Research Center, Deparment of Physiology, University of Maryland School of Medicine, 10 N. Greene St., Rm 4B-201, Baltimore, MD 21201, USA.
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Cid E, Cifuentes D, Baqué S, Ferrer JC, Guinovart JJ. Determinants of the nucleocytoplasmic shuttling of muscle glycogen synthase. FEBS J 2005; 272:3197-213. [PMID: 15955076 DOI: 10.1111/j.1742-4658.2005.04738.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Muscle glycogen synthase (MGS) presents a nuclear speckled pattern in primary cultured human muscle and in 3T3-L1 cells deprived of glucose and with depleted glycogen reserves. Nuclear accumulation of the enzyme correlates inversely with cellular glycogen content. Although the glucose-induced export of MGS from the nucleus to the cytoplasm is blocked by leptomycin B, and therefore mediated by CRM1, no nuclear export signal was identified in the sequence of the protein. Deletion analysis shows that the region comprising amino acids 555-633 of human MGS, which encompasses an Arg-rich cluster involved in the allosteric activation of the enzyme by Glc6P, is crucial for its nuclear concentration and aggregation. Mutation of these Arg residues, which desensitizes the enzyme towards Glc6P, interferes with its nuclear accumulation. In contrast, the known phosphorylation sites of MGS that regulate its activity are not involved in the control of its subcellular distribution. Nuclear human MGS co-localizes with the promyelocytic leukaemia oncoprotein and p80-coilin, a marker of Cajal bodies. The subnuclear distribution of MGS is altered by incubation with transcription inhibitors. These observations suggest that, in addition to its metabolic function, MGS may participate in nuclear processes.
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Affiliation(s)
- Emili Cid
- Departament de Bioquímica i Biologia Molecular, Universitat de Barcelona, Spain
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MacGregor EA. Possible structure and active site residues of starch, glycogen, and sucrose synthases. JOURNAL OF PROTEIN CHEMISTRY 2002; 21:297-306. [PMID: 12168700 DOI: 10.1023/a:1019701621256] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A group of enzymes that include muscle glycogen phosphorylase and sugar transferases involved in, for example, the glucosylation of DNA and the synthesis of peptidoglycan are known to possess the same basic three-dimensional fold. Here the possibility is examined that other monosaccharide transferases, those that catalyze synthesis of starch, glycogen, and the disaccharide sucrose, resemble the phosphorylase-type enzymes in structure. In particular, a clear relationship is shown, for the first time, between mammalian glycogen synthases and the phosphorylase structural group of proteins. Domain architecture and secondary structure are discussed, and the possible role of several conserved amino acids at the active site is explored.
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Affiliation(s)
- E Ann MacGregor
- Department of Chemistry, University of Manitoba, Winnipeg, Canada.
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Abstract
Red algae (Rhodophyceae) are photosynthetic eukaryotes that accumulate starch granules outside of their plastids. The starch granules from red algae (floridean starch) show structural similarities with higher plant starch granules but lack amylose. Recent studies have indicated that the extra-plastidic starch synthesis in red algae proceeds via a UDP glucose-selective alpha-glucan synthase, in analogy with the cytosolic pathway of glycogen synthesis in other eukaryotes. On the other hand, plastidic starch synthesis in green cells occurs selectively via ADP glucose in analogy with the pathway of glycogen synthesis in prokaryotes from which plastids have evolved. Given the emerging consensus of a monophyletic origin of plastids, it would appear that the capacity for starch synthesis selectively evolved from the alpha-glucan synthesizing machinery of the host ancestor and its endosymbiont in red algae and green algae, respectively. This implies the evolution of fundamentally different functional relationships between the different subcellular compartments with regard to photosynthetic carbon metabolism in these organisms. It is suggested that the biochemical and molecular elucidation of floridean starch synthesis may offer new insights into the metabolic strategies of photosynthetic eukaryotes.
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Affiliation(s)
- R Viola
- Scottish Crop Research Institute, Unit of Plant Biochemistry, Invergowrie, Dundee DD2 5DA, UK.
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Cid E, Gomis RR, Geremia RA, Guinovart JJ, Ferrer JC. Identification of two essential glutamic acid residues in glycogen synthase. J Biol Chem 2000; 275:33614-21. [PMID: 10924520 DOI: 10.1074/jbc.m005358200] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The detailed catalytic mechanism by which glycosyltransferases catalyze the transfer of a glycosyl residue from a donor sugar to an acceptor is not known. Through the multiple alignment of all known eukaryotic glycogen synthases we have found an invariant 17-amino acid stretch enclosed within the most conserved region of the members of this family. This peptide includes an E-X(7)-E motif, which is highly conserved in four families of retaining glycosyltransferases. Site-directed mutagenesis was performed in human muscle glycogen synthase to analyze the roles of the two conserved Glu residues (Glu-510 and Glu-518) of the motif. Proteins were transiently expressed in COS-1 cells as fusions to green fluorescence protein. The E510A and E518A mutant proteins retained the ability to translocate from the nucleus to the cytosol in response to glucose and to bind to intracellular glycogen. Although the E518A variant had approximately 6% of the catalytic activity shown by the green fluorescence protein-human muscle glycogen synthase fusion protein, the E510A mutation inactivated the enzyme. These results led us to conclude that the E-X(7)-E motif is part of the active site of eukaryotic glycogen synthases and that both conserved Glu residues are involved in catalysis. We propose that Glu-510 may function as the nucleophile and Glu-518 as the general acid/base catalyst.
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Affiliation(s)
- E Cid
- Departament de Bioquimica i Biologia Molecular, Universitat de Barcelona, Barcelona E-08028, Spain
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Williamson BD, Favis R, Brickey DA, Rutherford CL. Isolation and characterization of glycogen synthase in Dictyostelium discoideum. DEVELOPMENTAL GENETICS 2000; 19:350-64. [PMID: 9023987 DOI: 10.1002/(sici)1520-6408(1996)19:4<350::aid-dvg8>3.0.co;2-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We have partially purified the protein and isolated the glcS gene for glycogen synthase in Dictyostelium. glcS mRNA is present throughout development and is the product of a single gene coding for 775 amino acids, with a predicted molecular mass of 87 kD. The sequence is highly similar to glycogen synthase from human muscle, yeast, and rat liver, diverging significantly only at the amino and carboxy termini. Phosphorylation and UDPG binding sites are conserved, with K(m) values for UDPG being comparable to those determined for other organisms, but in vitro phosphorylation failing to convert between the G6P-dependent (D) and -independent (I) forms. Enzyme activity is relatively constant throughout the life cycle: the I form of the enzyme isolates with the soluble fraction in amoebae, switches to the D form, becomes pellet-associated during early development, and finally reverts during late development to the I form, which again localizes to the soluble fraction. Deletion analysis of the promoter reveals a GC-rich element which, when deleted, abolishes expression of glcS.
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Affiliation(s)
- B D Williamson
- Department of Biology, virginia Polytechnic Institute and State University, Blacksburg 24061-0406, USA
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Girón MD, Salto R, Hortelano P, Periago JL, Vargas AM, Suárez MD. Increased diaphragm expression of GLUT4 in control and streptozotocin-diabetic rats by fish oil-supplemented diets. Lipids 1999; 34:801-7. [PMID: 10529090 DOI: 10.1007/s11745-999-0426-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Dietary fat intake influences plasma glucose concentration through modifying glucose uptake and utilization by adipose and skeletal muscle tissues. In this paper, we studied the effects of a low-fat diet on diaphragm GLUT4 expression and fatty acid composition in control and streptozotocin-induced diabetic rats. Control as well as diabetic rats were divided into three different dietary groups each. Either 5% olive oil, 5% sunflower oil, or 5% fish oil was the only fat supplied by the diet. Feeding these low-fat diets for 5 wk induced major changes in fatty acid composition, both in control and in diabetic rats. Arachidonic acid was higher in diabetic olive and sunflower oil-fed rats with respect to fish oil-fed, opposite to docosahexaenoic acid which was higher in diabetic fish oil-fed rats with respect to the other two groups. Animals receiving a fish oil diet had the lowest plasma glucose concentration. GLUT4 expression in diaphragm, as indicated by GLUT4 protein and mRNA, is modulated both by diabetes and by diet fatty acid composition. Diabetes induced a decrease in expression in all dietary groups. Plasma glucose levels correlated well with the increased amount of GLUT4 protein and mRNA found in fish oil-fed groups. Results are discussed in terms of the influence that arachidonic and n-3 polyunsaturated fatty acids may exert on the transcriptional and translational control of the GLUT4 gene.
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Affiliation(s)
- M D Girón
- Department of Biochemistry and Molecular Biology, School of Pharmacy, University of Granada, Spain.
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Park KS, Ciaraldi TP, Abrams-Carter L, Mudaliar S, Nikoulina SE, Henry RR. Troglitazone regulation of glucose metabolism in human skeletal muscle cultures from obese type II diabetic subjects. J Clin Endocrinol Metab 1998; 83:1636-43. [PMID: 9589670 DOI: 10.1210/jcem.83.5.4764] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
To determine the effects of troglitazone on abnormal skeletal muscle glucose metabolism, muscle cultures from type II diabetic patients were grown for 4-6 weeks and then fused for 4 days either without or with troglitazone (1-5 micrograms/mL; chronic studies) or had troglitazone added for 90 min (1-5 micrograms/mL) at completion of fusion (acute studies). Acute troglitazone treatment stimulated glucose uptake, but not glycogen synthase (GS) activity 2-fold (P < 0.05) in a dose-dependent fashion and to the same extent as the addition of maximal (33 nmol/L) insulin. Maximal chronic troglitazone (5 micrograms/mL for 4 days) increased both glucose uptake (from 9.0 +/- 1.5 to 40.9 +/- 8.1 pmol/mg protein.min; P < 0.05) and GS fractional velocity (from 5.4 +/- 0.7% to 20.6 +/- 6.3%; P < 0.05) by approximately 4-fold. At each concentration of chronic troglitazone, glucose uptake rates were similar in the absence and presence of maximal (33 nmol/L) insulin concentrations. In contrast, insulin-stimulated GS activity was greater (P < 0.05) when maximal chronic troglitazone and acute insulin were combined than when chronic troglitazone alone was used. After 4 days of troglitazone, GLUT1 messenger ribonucleic acid and protein increased about 2-fold (P < 0.05) without a change in GLUT4 or GS messenger ribonucleic acid and protein. We conclude that troglitazone has both acute and chronic effects to improve skeletal muscle glucose metabolism of obese type II diabetic subjects. These effects involve direct insulin mimetic stimulatory actions as well as indirect insulin-sensitizing properties.
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Affiliation(s)
- K S Park
- Department of Medicine, University of California-San Diego, La Jolla 92093, USA
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Rissanen J, Pihlajamäki J, Heikkinen S, Kekäläinen P, Mykkänen L, Kuusisto J, Kolle A, Laakso M. New variants in the glycogen synthase gene (Gln71His, Met416Val) in patients with NIDDM from eastern Finland. Diabetologia 1997; 40:1313-9. [PMID: 9389424 DOI: 10.1007/s001250050826] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Impaired glycogen synthesis after insulin stimulation accounts for most of the insulin resistance in patients with non-insulin-dependent diabetes mellitus (NIDDM). The glycogen synthase gene (GYS1), which encodes the rate-limiting enzyme for glycogen synthesis, is a promising candidate gene for NIDDM. Therefore, we screened all 16 exons of this gene by single-strand conformation polymorphism analysis in 40 patients with NIDDM (age 67 +/- 2 years, body mass index 28.2 +/- 0.6 kg/m2) from Taipalsaari, eastern Finland. The Gly464Ser variant (exon 11) and a silent polymorphism TTC342TTT (exon 7) have been reported previously. In addition, we found a new variant Gln71His (exon 2) and a new amino acid polymorphism Met416Val (exon 10). An additional sample of 65 patients with NIDDM and 82 normoglycaemic men (age 54 +/- 1 years, body mass index 26.3 +/- 1.4 kg/m2) were screened. The allele frequency of the TTC342TTT silent substitution was 0.29 in both NIDDM and normoglycaemic subjects. The Gln71His and Gly464Ser variants were found in 1 (1%) and 3 (3%) subjects, respectively, of the 105 NIDDM patients and in none of the 82 normoglycaemic men. The Met416Val polymorphism was found in 16 (15%) of the 105 NIDDM patients and in 14 (17%) of the 82 control subjects (all heterozygous). The Met416Val polymorphism was not associated with insulin resistance in two groups of normoglycaemic subjects. In conclusion, the new Gln71His and Met416Val substitutions and other variants of the glycogen synthase gene are unlikely to make a major contribution to insulin resistance and NIDDM in diabetic patients from eastern Finland.
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Affiliation(s)
- J Rissanen
- Department of Medicine, University of Kuopio, Finland
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50
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Ferrer JC, Baqué S, Guinovart JJ. Muscle glycogen synthase translocates from the cell nucleus to the cystosol in response to glucose. FEBS Lett 1997; 415:249-52. [PMID: 9357976 DOI: 10.1016/s0014-5793(97)01136-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We have studied the intracellular localization of muscular glycogen synthase by fusing the green fluorescent protein (GFP) of the jelly-fish Aequorea victoria to the N-terminus of human muscle glycogen synthase (HMGS), and expressing the chimeric protein in C2C12, COS-1 cells, and primary cultured rat hepatocytes. In contrast to what we have recently found for the hepatic glycogen synthase (Fernandez-Novell et al. (1997) Biochem. J. 321, 227-231), the GFP/HMGS fusion protein is localized to the nucleus of the cell in the absence of glucose, and in the presence of the sugar it is essentially found in the cytosol. Insulin is not required for the translocation of the enzyme.
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Affiliation(s)
- J C Ferrer
- Departament de Bioquímica i Biologia Molecular, Universitat de Barcelona, Martí i Franquès, Spain
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