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Song H, Wang B, Zhao G, Lu S, Zhang D, Kong J, Li J, Zhang X, Lyu Y, Liu L. Discovery and biochemical characterization of two hexokinases from Crassostrea gigas. Protein Expr Purif 2024; 215:106408. [PMID: 38008389 DOI: 10.1016/j.pep.2023.106408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 11/20/2023] [Accepted: 11/21/2023] [Indexed: 11/28/2023]
Abstract
Hexokinases (HKs) play a vital role in glucose metabolism, which controls the first committed step catalyzing the production of glucose-6-phosphate from glucose. Two HKs (CGIHK1 and CGIHK2) from the Pacific oyster Crassostrea giga were cloned and characterized. CGIHK1 and CGIHK2 were recombinantly expressed in Escherichia coli and successfully purified by the Ni-NTA column. The optimum pH of the two enzymes was pH 8.0 and 8.5, respectively. The optimum temperature of the two enzymes was 42 °C and 50 °C, respectively. Both enzymes showed a clear requirement for divalent magnesium and were strongly inhibited by SDS. CGIHK1 exhibited highly strict substrate specificity to glucose, while CGIHK2 could also catalyze other 11 monosaccharide substrates. This is the first report on the in vitro biosynthesis of glucose-6-phosphate by the hexokinases from Crassostrea gigas. The facile expression and purification procedures combined with different substrate specificities make CGIHK1 and CGIHK2 candidates for the biosynthesis of glucose-6-phosphate and other sugar-phosphates.
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Affiliation(s)
- Huibo Song
- College of Agricultural and Biological Engineering (College of Tree Peony), Heze University, Heze, 274015, China; Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Bo Wang
- College of Agricultural and Biological Engineering (College of Tree Peony), Heze University, Heze, 274015, China
| | - Guihong Zhao
- College of Agricultural and Biological Engineering (College of Tree Peony), Heze University, Heze, 274015, China.
| | - Shihai Lu
- Shandong Bigtree Dreyfus Special Meals Food Co., Ltd, Heze, 274000, China
| | - Dahu Zhang
- Shandong Bigtree Dreyfus Special Meals Food Co., Ltd, Heze, 274000, China
| | - Jianbiao Kong
- Heze Product Inspection and Testing Research Institute, Heze, 274000, China
| | - Jianxin Li
- Heze Institute for Food and Drug Control. Heze, 274000, China
| | - Xiaoyang Zhang
- School of Marine and Bioengineering, Yancheng Institute of Technology, Yancheng, 224051, China
| | - Yongmei Lyu
- School of Marine and Bioengineering, Yancheng Institute of Technology, Yancheng, 224051, China
| | - Li Liu
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China.
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2
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Krishnamurthy KA, Rutten MGS, Hoogerland JA, van Dijk TH, Bos T, Koehorst M, de Vries MP, Kloosterhuis NJ, Havinga H, Schomakers BV, van Weeghel M, Wolters JC, Bakker BM, Oosterveer MH. Hepatic ChREBP orchestrates intrahepatic carbohydrate metabolism to limit hepatic glucose 6-phosphate and glycogen accumulation in a mouse model for acute Glycogen Storage Disease type Ib. Mol Metab 2024; 79:101838. [PMID: 37995884 PMCID: PMC10716006 DOI: 10.1016/j.molmet.2023.101838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 11/13/2023] [Indexed: 11/25/2023] Open
Abstract
OBJECTIVE Carbohydrate Response Element Binding Protein (ChREBP) is a glucose 6-phosphate (G6P)-sensitive transcription factor that acts as a metabolic switch to maintain intracellular glucose and phosphate homeostasis. Hepatic ChREBP is well-known for its regulatory role in glycolysis, the pentose phosphate pathway, and de novo lipogenesis. The physiological role of ChREBP in hepatic glycogen metabolism and blood glucose regulation has not been assessed in detail, and ChREBP's contribution to carbohydrate flux adaptations in hepatic Glycogen Storage Disease type 1 (GSD I) requires further investigation. METHODS The current study aimed to investigate the role of ChREBP as a regulator of glycogen metabolism in response to hepatic G6P accumulation, using a model for acute hepatic GSD type Ib. The immediate biochemical and regulatory responses to hepatic G6P accumulation were evaluated upon G6P transporter inhibition by the chlorogenic acid S4048 in mice that were either treated with a short hairpin RNA (shRNA) directed against ChREBP (shChREBP) or a scrambled shRNA (shSCR). Complementary stable isotope experiments were performed to quantify hepatic carbohydrate fluxes in vivo. RESULTS ShChREBP treatment normalized the S4048-mediated induction of hepatic ChREBP target genes to levels observed in vehicle- and shSCR-treated controls. In parallel, hepatic shChREBP treatment in S4048-infused mice resulted in a more pronounced accumulation of hepatic glycogen and further reduction of blood glucose levels compared to shSCR treatment. Hepatic ChREBP knockdown modestly increased glucokinase (GCK) flux in S4048-treated mice while it enhanced UDP-glucose turnover as well as glycogen synthase and phosphorylase fluxes. Hepatic GCK mRNA and protein levels were induced by shChREBP treatment in both vehicle- and S4048-treated mice, while glycogen synthase 2 (GYS2) and glycogen phosphorylase (PYGL) mRNA and protein levels were reduced. Finally, knockdown of hepatic ChREBP expression reduced starch domain binding protein 1 (STBD1) mRNA and protein levels while it inhibited acid alpha-glucosidase (GAA) activity, suggesting reduced capacity for lysosomal glycogen breakdown. CONCLUSIONS Our data show that ChREBP activation controls hepatic glycogen and blood glucose levels in acute hepatic GSD Ib through concomitant regulation of glucose phosphorylation, glycogenesis, and glycogenolysis. ChREBP-mediated control of GCK enzyme levels aligns with corresponding adaptations in GCK flux. In contrast, ChREBP activation in response to acute hepatic GSD Ib exerts opposite effects on GYS2/PYGL enzyme levels and their corresponding fluxes, indicating that GYS2/PYGL expression levels are not limiting to their respective fluxes under these conditions.
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Affiliation(s)
- K A Krishnamurthy
- Laboratory of Pediatrics, University of Groningen, University Medical Center Groningen, The Netherlands
| | - M G S Rutten
- Laboratory of Pediatrics, University of Groningen, University Medical Center Groningen, The Netherlands
| | - J A Hoogerland
- Laboratory of Pediatrics, University of Groningen, University Medical Center Groningen, The Netherlands
| | - T H van Dijk
- Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, The Netherlands
| | - T Bos
- Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, The Netherlands
| | - M Koehorst
- Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, The Netherlands
| | - M P de Vries
- Laboratory of Pediatrics, University of Groningen, University Medical Center Groningen, The Netherlands; Interfaculty Mass Spectrometry Center, University of Groningen, University Medical Center Groningen, The Netherlands
| | - N J Kloosterhuis
- Laboratory of Pediatrics, University of Groningen, University Medical Center Groningen, The Netherlands
| | - H Havinga
- Laboratory of Pediatrics, University of Groningen, University Medical Center Groningen, The Netherlands
| | - B V Schomakers
- Laboratory Genetic Metabolic Diseases, UMC Amsterdam, The Netherlands; Core Facility Metabolomics, UMC Amsterdam, The Netherlands
| | - M van Weeghel
- Laboratory Genetic Metabolic Diseases, UMC Amsterdam, The Netherlands; Core Facility Metabolomics, UMC Amsterdam, The Netherlands
| | - J C Wolters
- Laboratory of Pediatrics, University of Groningen, University Medical Center Groningen, The Netherlands; Interfaculty Mass Spectrometry Center, University of Groningen, University Medical Center Groningen, The Netherlands
| | - B M Bakker
- Laboratory of Pediatrics, University of Groningen, University Medical Center Groningen, The Netherlands
| | - M H Oosterveer
- Laboratory of Pediatrics, University of Groningen, University Medical Center Groningen, The Netherlands; Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, The Netherlands.
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Hawes EM, Boortz KA, Oeser JK, O’Rourke ML, O’Brien RM. G6PC1 and G6PC2 influence G6P flux but not HSD11B1 activity. J Mol Endocrinol 2023; 71:e230070. [PMID: 37855366 PMCID: PMC10616506 DOI: 10.1530/jme-23-0070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 09/19/2023] [Indexed: 09/21/2023]
Abstract
In the endoplasmic reticulum (ER) lumen, glucose-6-phosphatase catalytic subunit 1 and 2 (G6PC1; G6PC2) hydrolyze glucose-6-phosphate (G6P) to glucose and inorganic phosphate whereas hexose-6-phosphate dehydrogenase (H6PD) hydrolyzes G6P to 6-phosphogluconate (6PG) in a reaction that generates NADPH. 11β-hydroxysteroid dehydrogenase type 1 (HSD11B1) utilizes this NADPH to convert inactive cortisone to cortisol. HSD11B1 inhibitors improve insulin sensitivity whereas G6PC inhibitors are predicted to lower fasting blood glucose (FBG). This study investigated whether G6PC1 and G6PC2 influence G6P flux through H6PD and vice versa. Using a novel transcriptional assay that utilizes separate fusion genes to quantitate glucocorticoid and glucose signaling, we show that overexpression of H6PD and HSD11B1 in the islet-derived 832/13 cell line activated glucocorticoid-stimulated fusion gene expression. Overexpression of HSD11B1 blunted glucose-stimulated fusion gene expression independently of altered G6P flux. While overexpression of G6PC1 and G6PC2 blunted glucose-stimulated fusion gene expression, it had minimal effect on glucocorticoid-stimulated fusion gene expression. In the liver-derived HepG2 cell line, overexpression of H6PD and HSD11B1 activated glucocorticoid-stimulated fusion gene expression but overexpression of G6PC1 and G6PC2 had no effect. In rodents, HSD11B1 converts 11-dehydrocorticosterone (11-DHC) to corticosterone. Studies in wild-type and G6pc2 knockout mice treated with 11-DHC for 5 weeks reveal metabolic changes unaffected by the absence of G6PC2. These data suggest that HSD11B1 activity is not significantly affected by the presence or absence of G6PC1 or G6PC2. As such, G6PC1 and G6PC2 inhibitors are predicted to have beneficial effects by reducing FBG without causing a deleterious increase in glucocorticoid signaling.
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Affiliation(s)
- Emily M. Hawes
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Kayla A. Boortz
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - James K. Oeser
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Margaret L. O’Rourke
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Richard M. O’Brien
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232
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Silkenath B, Kläge D, Altwein H, Schmidhäuser N, Mayer G, Hartig JS, Wittmann V. Phosphonate and Thiasugar Analogues of Glucosamine-6-phosphate: Activation of the glmS Riboswitch and Antibiotic Activity. ACS Chem Biol 2023; 18:2324-2334. [PMID: 37793187 PMCID: PMC10594590 DOI: 10.1021/acschembio.3c00452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 09/19/2023] [Indexed: 10/06/2023]
Abstract
The glmS riboswitch is a motif found in 5'-untranslated regions of bacterial mRNA that controls the synthesis of glucosamine-6-phosphate (GlcN6P), an essential building block for the bacterial cell wall, by a feedback mechanism. Activation of the glmS riboswitch by GlcN6P mimics interferes with the ability of bacteria to synthesize its cell wall. Accordingly, GlcN6P mimics acting as glmS activators are promising candidates for future antibiotic drugs that may overcome emerging bacterial resistance against established antibiotics. We describe the synthesis of a series of phosphonate mimics of GlcN6P as well as the thiasugar analogue of GlcN6P. The phosphonate mimics differ in their pKa value to answer the question of whether derivatives with a pKa matching that of GlcN6P would be efficient glmS activators. We found that all derivatives activate the riboswitch, however, less efficiently than GlcN6P. This observation can be explained by the missing hydrogen bonds in the case of phosphonates and is valuable information for the design of future GlcN6P mimics. The thiasugar analogue of GlcN6P on the other hand turned out to be a glmS riboswitch activator with the same activity as the natural metabolite GlcN6P. The nonphosphorylated thiasugar displayed antimicrobial activity against certain bacilli. Therefore, the compound is a promising lead structure for the development of future antibiotics with a potentially novel mode of action.
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Affiliation(s)
- Bjarne Silkenath
- Department
of Chemistry, University of Konstanz, 78457 Konstanz, Germany
| | - Dennis Kläge
- Department
of Chemistry, University of Konstanz, 78457 Konstanz, Germany
| | - Hanna Altwein
- Department
of Chemistry, University of Konstanz, 78457 Konstanz, Germany
| | - Nina Schmidhäuser
- Department
of Chemistry, University of Konstanz, 78457 Konstanz, Germany
| | - Günter Mayer
- LIMES
Institute, Center for Aptamer Research & Development, University of Bonn, 53121 Bonn, Germany
| | - Jörg S. Hartig
- Department
of Chemistry, University of Konstanz, 78457 Konstanz, Germany
| | - Valentin Wittmann
- Department
of Chemistry, University of Konstanz, 78457 Konstanz, Germany
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5
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Gámez-Arcas S, Muñoz FJ, Ricarte-Bermejo A, Sánchez-López ÁM, Baslam M, Baroja-Fernández E, Bahaji A, Almagro G, De Diego N, Doležal K, Novák O, Leal-López J, León Morcillo RJ, Castillo AG, Pozueta-Romero J. Glucose-6-P/phosphate translocator2 mediates the phosphoglucose-isomerase1-independent response to microbial volatiles. Plant Physiol 2022; 190:2137-2154. [PMID: 36111879 PMCID: PMC9706466 DOI: 10.1093/plphys/kiac433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 08/26/2022] [Indexed: 06/15/2023]
Abstract
In Arabidopsis (Arabidopsis thaliana), the plastidial isoform of phosphoglucose isomerase (PGI1) mediates photosynthesis, metabolism, and development, probably due to its involvement in the synthesis of isoprenoid-derived signals in vascular tissues. Microbial volatile compounds (VCs) with molecular masses of <45 Da promote photosynthesis, growth, and starch overaccumulation in leaves through PGI1-independent mechanisms. Exposure to these compounds in leaves enhances the levels of GLUCOSE-6-PHOSPHATE/PHOSPHATE TRANSLOCATOR2 (GPT2) transcripts. We hypothesized that the PGI1-independent response to microbial volatile emissions involves GPT2 action. To test this hypothesis, we characterized the responses of wild-type (WT), GPT2-null gpt2-1, PGI1-null pgi1-2, and pgi1-2gpt2-1 plants to small fungal VCs. In addition, we characterized the responses of pgi1-2gpt2-1 plants expressing GPT2 under the control of a vascular tissue- and root tip-specific promoter to small fungal VCs. Fungal VCs promoted increases in growth, starch content, and photosynthesis in WT and gpt2-1 plants. These changes were substantially weaker in VC-exposed pgi1-2gpt2-1 plants but reverted to WT levels with vascular and root tip-specific GPT2 expression. Proteomic analyses did not detect enhanced levels of GPT2 protein in VC-exposed leaves and showed that knocking out GPT2 reduced the expression of photosynthesis-related proteins in pgi1-2 plants. Histochemical analyses of GUS activity in plants expressing GPT2-GUS under the control of the GPT2 promoter showed that GPT2 is mainly expressed in root tips and vascular tissues around hydathodes. Overall, the data indicated that the PGI1-independent response to microbial VCs involves resetting of the photosynthesis-related proteome in leaves through long-distance GPT2 action.
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Affiliation(s)
- Samuel Gámez-Arcas
- Instituto de Agrobiotecnología (IdAB), CSIC-Gobierno de Navarra, Iruñako etorbidea 123, 31192 Mutiloabeti, Nafarroa, Spain
| | | | - Adriana Ricarte-Bermejo
- Instituto de Agrobiotecnología (IdAB), CSIC-Gobierno de Navarra, Iruñako etorbidea 123, 31192 Mutiloabeti, Nafarroa, Spain
| | - Ángela María Sánchez-López
- Instituto de Agrobiotecnología (IdAB), CSIC-Gobierno de Navarra, Iruñako etorbidea 123, 31192 Mutiloabeti, Nafarroa, Spain
| | - Marouane Baslam
- Instituto de Agrobiotecnología (IdAB), CSIC-Gobierno de Navarra, Iruñako etorbidea 123, 31192 Mutiloabeti, Nafarroa, Spain
- Laboratory of Biochemistry, Faculty of Agriculture, Niigata University, Niigata 950-2181, Japan
| | - Edurne Baroja-Fernández
- Instituto de Agrobiotecnología (IdAB), CSIC-Gobierno de Navarra, Iruñako etorbidea 123, 31192 Mutiloabeti, Nafarroa, Spain
| | - Abdellatif Bahaji
- Instituto de Agrobiotecnología (IdAB), CSIC-Gobierno de Navarra, Iruñako etorbidea 123, 31192 Mutiloabeti, Nafarroa, Spain
| | - Goizeder Almagro
- Instituto de Agrobiotecnología (IdAB), CSIC-Gobierno de Navarra, Iruñako etorbidea 123, 31192 Mutiloabeti, Nafarroa, Spain
| | - Nuria De Diego
- Centre of Region Haná for Biotechnological and Agricultural Research, Czech Advanced Technology and Research Institute, Olomouc, Czech Republic
| | - Karel Doležal
- Department of Chemical Biology, Faculty of Science, Palacký University, Olomouc CZ-78371, Czech Republic
- Laboratory of Growth Regulators, Faculty of Science of Palacký University and Institute of Experimental Botany of the Czech Academy of Sciences, Olomouc CZ-78371, Czech Republic
| | - Ondřej Novák
- Laboratory of Growth Regulators, Faculty of Science of Palacký University and Institute of Experimental Botany of the Czech Academy of Sciences, Olomouc CZ-78371, Czech Republic
| | - Jesús Leal-López
- Institute for Mediterranean and Subtropical Horticulture “La Mayora” (IHSM), CSIC-UMA, 29010 Málaga, Spain
| | - Rafael Jorge León Morcillo
- Institute for Mediterranean and Subtropical Horticulture “La Mayora” (IHSM), CSIC-UMA, 29010 Málaga, Spain
| | - Araceli G Castillo
- Institute for Mediterranean and Subtropical Horticulture “La Mayora” (IHSM), CSIC-UMA, 29010 Málaga, Spain
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Kopczewski T, Kuźniak E, Ciereszko I, Kornaś A. Alterations in Primary Carbon Metabolism in Cucumber Infected with Pseudomonas syringae pv lachrymans: Local and Systemic Responses. Int J Mol Sci 2022; 23:ijms232012418. [PMID: 36293272 PMCID: PMC9603868 DOI: 10.3390/ijms232012418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 10/07/2022] [Accepted: 10/11/2022] [Indexed: 11/23/2022] Open
Abstract
The reconfiguration of the primary metabolism is essential in plant–pathogen interactions. We compared the local metabolic responses of cucumber leaves inoculated with Pseudomonas syringae pv lachrymans (Psl) with those in non-inoculated systemic leaves, by examining the changes in the nicotinamide adenine dinucleotides pools, the concentration of soluble carbohydrates and activities/gene expression of carbohydrate metabolism-related enzymes, the expression of photosynthesis-related genes, and the tricarboxylic acid cycle-linked metabolite contents and enzyme activities. In the infected leaves, Psl induced a metabolic signature with an altered [NAD(P)H]/[NAD(P)+] ratio; decreased glucose and sucrose contents, along with a changed invertase gene expression; and increased glucose turnover and accumulation of raffinose, trehalose, and myo-inositol. The accumulation of oxaloacetic and malic acids, enhanced activities, and gene expression of fumarase and l-malate dehydrogenase, as well as the increased respiration rate in the infected leaves, indicated that Psl induced the tricarboxylic acid cycle. The changes in gene expression of ribulose-l,5-bis-phosphate carboxylase/oxygenase large unit, phosphoenolpyruvate carboxylase and chloroplast glyceraldehyde-3-phosphate dehydrogenase were compatible with a net photosynthesis decline described earlier. Psl triggered metabolic changes common to the infected and non-infected leaves, the dynamics of which differed quantitatively (e.g., malic acid content and metabolism, glucose-6-phosphate accumulation, and glucose-6-phosphate dehydrogenase activity) and those specifically related to the local or systemic response (e.g., changes in the sugar content and turnover). Therefore, metabolic changes in the systemic leaves may be part of the global effects of local infection on the whole-plant metabolism and also represent a specific acclimation response contributing to balancing growth and defense.
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Affiliation(s)
- Tomasz Kopczewski
- Department of Plant Physiology and Biochemistry, Faculty of Biology and Environmental Protection, University of Lodz, 90-237 Lodz, Poland
| | - Elżbieta Kuźniak
- Department of Plant Physiology and Biochemistry, Faculty of Biology and Environmental Protection, University of Lodz, 90-237 Lodz, Poland
- Correspondence:
| | - Iwona Ciereszko
- Department of Plant Biology and Ecology, Faculty of Biology, University of Bialystok, 15-245 Bialystok, Poland
| | - Andrzej Kornaś
- Institute of Biology, Pedagogical University of Krakow, 30-084 Kraków, Poland
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7
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Leng L, Yuan Z, Pan R, Su X, Wang H, Xue J, Zhuang K, Gao J, Chen Z, Lin H, Xie W, Li H, Chen Z, Ren K, Zhang X, Wang W, Jin ZB, Wu S, Wang X, Yuan Z, Xu H, Chow HM, Zhang J. Microglial hexokinase 2 deficiency increases ATP generation through lipid metabolism leading to β-amyloid clearance. Nat Metab 2022; 4:1287-1305. [PMID: 36203054 DOI: 10.1038/s42255-022-00643-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 08/18/2022] [Indexed: 01/20/2023]
Abstract
Microglial cells consume adenosine triphosphate (ATP) during phagocytosis to clear neurotoxic β-amyloid in Alzheimer's disease (AD). However, the contribution of energy metabolism to microglial function in AD remains unclear. Here, we demonstrate that hexokinase 2 (HK2) is elevated in microglia from an AD mouse model (5xFAD) and AD patients. Genetic deletion or pharmacological inhibition of HK2 significantly promotes microglial phagocytosis, lowers the amyloid plaque burden and attenuates cognitive impairment in male AD mice. Notably, the ATP level is dramatically increased in HK2-deficient or inactive microglia, which can be attributed to a marked upregulation in lipoprotein lipase (LPL) expression and subsequent increase in lipid metabolism. We further show that two downstream metabolites of HK2, glucose-6-phosphate and fructose-6-phosphate, can reverse HK2-deficiency-induced upregulation of LPL, thus supporting ATP production and microglial phagocytosis. Our findings uncover a crucial role for HK2 in phagocytosis through regulation of microglial energy metabolism, suggesting a potential therapeutic strategy for AD by targeting HK2.
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Affiliation(s)
- Lige Leng
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China.
| | - Ziqi Yuan
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Ruiyuan Pan
- The Brain Science Center, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Xiao Su
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Han Wang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Jin Xue
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Kai Zhuang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Ju Gao
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Zhenlei Chen
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Hui Lin
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Wenting Xie
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Huifang Li
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Zhenyi Chen
- Department of Anesthesiology, First Affiliated Hospital of Xiamen University, Xiamen, Fujian, China
| | - Keke Ren
- Department of Neurobiology, School of Basic Medicine, Fourth Military Medcial University, Xi'an, Shaanxi, China
| | - Xiao Zhang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China
| | - Wenting Wang
- Department of Neurobiology, School of Basic Medicine, Fourth Military Medcial University, Xi'an, Shaanxi, China
| | - Zi-Bing Jin
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China
| | - Shengxi Wu
- Department of Neurobiology, School of Basic Medicine, Fourth Military Medcial University, Xi'an, Shaanxi, China
| | - Xinglong Wang
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Zengqiang Yuan
- The Brain Science Center, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Huaxi Xu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Hei-Man Chow
- School of Life Sciences, The Chinese University of Hong Kong, Sha Tin, Hong Kong
| | - Jie Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China.
- Department of Anesthesiology, First Affiliated Hospital of Xiamen University, Xiamen, Fujian, China.
- Institute of Neuroscience, Fujian Medical University, Fuzhou, China.
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8
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Xia N, Guo X, Guo Q, Gupta N, Ji N, Shen B, Xiao L, Feng Y. Metabolic flexibilities and vulnerabilities in the pentose phosphate pathway of the zoonotic pathogen Toxoplasma gondii. PLoS Pathog 2022; 18:e1010864. [PMID: 36121870 PMCID: PMC9521846 DOI: 10.1371/journal.ppat.1010864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 09/29/2022] [Accepted: 09/08/2022] [Indexed: 11/18/2022] Open
Abstract
Metabolic pathways underpin the growth and virulence of intracellular parasites and are therefore promising antiparasitic targets. The pentose phosphate pathway (PPP) is vital in most organisms, providing a reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) and ribose sugar for nucleotide synthesis; however, it has not yet been studied in Toxoplasma gondii, a widespread intracellular pathogen and a model protozoan organism. Herein, we show that T. gondii has a functional PPP distributed in the cytoplasm and nucleus of its acutely-infectious tachyzoite stage. We produced eight parasite mutants disrupting seven enzymes of the PPP in T. gondii. Our data show that of the seven PPP proteins, the two glucose-6-phosphate dehydrogenases (TgG6PDH1, TgG6PDH2), one of the two 6-phosphogluconate dehydrogenases (Tg6PGDH1), ribulose-5-phosphate epimerase (TgRuPE) and transaldolase (TgTAL) are dispensable in vitro as well as in vivo, disclosing substantial metabolic plasticity in T. gondii. Among these, TgG6PDH2 plays a vital role in defense against oxidative stress by the pathogen. Further, we show that Tg6PGDH2 and ribulose-5-phosphate isomerase (TgRPI) are critical for tachyzoite growth. The depletion of TgRPI impairs the flux of glucose in central carbon pathways, and causes decreased expression of ribosomal, microneme and rhoptry proteins. In summary, our results demonstrate the physiological need of the PPP in T. gondii while unraveling metabolic flexibility and antiparasitic targets. Metabolic pathways are intimately associated with the survival and replication of parasitic Toxoplasma gondii and thus represent potential targets for antiparasitic strategies. Herein, we focused on the pentose phosphate pathway (PPP) in T. gondii and examined its roles in supporting the growth of this ubiquitous pathogen. We found that TgG6PDH1 and TgG6PDH2 were needed to defend oxidative stress but not for pentose synthesis. We revealed that inactivation of the Tg6PGDH2 and TgRPI severely impaired the asexual reproduction of tachyzoites. We also highlighted the remarkable metabolic plasticity in tachyzoites that enables them to acquire some of the PPP intermediates from multiple routes. This study provides significant insights into the carbon metabolism properties of Toxoplasma parasites, opening avenues for targeting this pathway to develop therapeutic interventions against toxoplasmosis.
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Affiliation(s)
- Ningbo Xia
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Xuefang Guo
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Qinghong Guo
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Nishith Gupta
- Department of Biological Sciences, Birla Institute of Technology and Science, Pilani (Hyderabad Campus), Hyderabad, India
- Department of Molecular Parasitology, Faculty of Life Sciences, Humboldt University, Berlin, Germany
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Nuo Ji
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Bang Shen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- * E-mail: (BS); (LX); (YF)
| | - Lihua Xiao
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- * E-mail: (BS); (LX); (YF)
| | - Yaoyu Feng
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- * E-mail: (BS); (LX); (YF)
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9
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Nasr Esfahani M, Kusano M, Abdelrahman M, Nguyen KH, Watanabe Y, Mochida K, Burritt DJ, Tran LSP. Differential metabolic rearrangements in the roots and leaves of Cicer arietinum caused by single or double nitrate and/or phosphate deficiencies. Plant J 2022; 111:1643-1659. [PMID: 35862290 DOI: 10.1111/tpj.15913] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 07/11/2022] [Accepted: 07/14/2022] [Indexed: 06/15/2023]
Abstract
Nitrate (NO3 - ) and phosphate (Pi) deficiencies are the major constraints for chickpea productivity, significantly impacting global food security. However, excessive fertilization is expensive and can also lead to environmental pollution. Therefore, there is an urgent need to develop chickpea cultivars that are able to grow on soils deficient in both NO3 - and Pi. This study focused on the identification of key NO3 - and/or Pi starvation-responsive metabolic pathways in the leaves and roots of chickpea grown under single and double nutrient deficiencies of NO3 - and Pi, in comparison with nutrient-sufficient conditions. A global metabolite analysis revealed organ-specific differences in the metabolic adaptation to nutrient deficiencies. Moreover, we found stronger adaptive responses in the roots and leaves to any single than combined nutrient-deficient stresses. For example, chickpea enhanced the allocation of carbon among nitrogen-rich amino acids (AAs) and increased the production of organic acids in roots under NO3 - deficiency, whereas this adaptive response was not found under double nutrient deficiency. Nitrogen remobilization through the transport of AAs from leaves to roots was greater under NO3 - deficiency than double nutrient deficiency conditions. Glucose-6-phosphate and fructose-6-phosphate accumulated in the roots under single nutrient deficiencies, but not under double nutrient deficiency, and higher glycolytic pathway activities were observed in both roots and leaves under single nutrient deficiency than double nutrient deficiency. Hence, the simultaneous deficiency generated a unique profile of metabolic changes that could not be simply described as the result of the combined deficiencies of the two nutrients.
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Affiliation(s)
| | - Miyako Kusano
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, 305-8572, Japan
- RIKEN Center for Sustainable Resource Science, Tsurumi, Yokohama, 230-0045, Japan
- Tsukuba Plant Innovation Research Center, University of Tsukuba, Tsukuba, 305-8572, Japan
| | - Mostafa Abdelrahman
- Molecular Biotechnology Program, Faculty of Science, Galala University, Suze, new Galala, 43511, Egypt
- Botany Department, Faculty of Science, Aswan, 81528, Egypt
| | - Kien Huu Nguyen
- Agricultural Genetics Institute, Vietnam Academy of Agricultural Sciences, Hanoi, Vietnam
| | - Yasuko Watanabe
- Bioproductivity Informatics Research Team, RIKEN Center for Sustainable Resource Science, Yokohama, 230-0045, Japan
| | - Keiichi Mochida
- Bioproductivity Informatics Research Team, RIKEN Center for Sustainable Resource Science, Yokohama, 230-0045, Japan
- School of Information and Data Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki, 852-8521, Japan
- Kihara Institute for Biological Research, Yokohama City University, 641-12 Maioka-cho, Totsuka-ku, Yokohama, Kanagawa, 244-0813, Japan
- RIKEN Baton Zone Program, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
| | - David J Burritt
- Department of Botany, University of Otago, P.O. Box 56, Dunedin, New Zealand
| | - Lam-Son Phan Tran
- Bioproductivity Informatics Research Team, RIKEN Center for Sustainable Resource Science, Yokohama, 230-0045, Japan
- Institute of Research and Development, Duy Tan University, Da Nang, 550000, Vietnam
- Institute of Genomics for Crop Abiotic Stress Tolerance, Department of Plant and Soil Science, Texas Tech University, Lubbock, Texas, 79409, USA
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10
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McCorvie TJ, Loria PM, Tu M, Han S, Shrestha L, Froese DS, Ferreira IM, Berg AP, Yue WW. Molecular basis for the regulation of human glycogen synthase by phosphorylation and glucose-6-phosphate. Nat Struct Mol Biol 2022; 29:628-638. [PMID: 35835870 PMCID: PMC9287172 DOI: 10.1038/s41594-022-00799-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 05/02/2022] [Indexed: 11/17/2022]
Abstract
Glycogen synthase (GYS1) is the central enzyme in muscle glycogen biosynthesis. GYS1 activity is inhibited by phosphorylation of its amino (N) and carboxyl (C) termini, which is relieved by allosteric activation of glucose-6-phosphate (Glc6P). We present cryo-EM structures at 3.0-4.0 Å resolution of phosphorylated human GYS1, in complex with a minimal interacting region of glycogenin, in the inhibited, activated and catalytically competent states. Phosphorylations of specific terminal residues are sensed by different arginine clusters, locking the GYS1 tetramer in an inhibited state via intersubunit interactions. The Glc6P activator promotes conformational change by disrupting these interactions and increases the flexibility of GYS1, such that it is poised to adopt a catalytically competent state when the sugar donor UDP-glucose (UDP-glc) binds. We also identify an inhibited-like conformation that has not transitioned into the activated state, in which the locking interaction of phosphorylation with the arginine cluster impedes subsequent conformational changes due to Glc6P binding. Our results address longstanding questions regarding the mechanism of human GYS1 regulation.
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Affiliation(s)
- Thomas J McCorvie
- Centre for Medicines Discovery, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
- Biosciences Institute, The Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Paula M Loria
- Discovery Sciences, Worldwide Research and Development, Pfizer Inc., Groton, CT, USA
| | - Meihua Tu
- Medicine Design, Worldwide Research and Development, Pfizer Inc., Cambridge, MA, USA
| | - Seungil Han
- Discovery Sciences, Worldwide Research and Development, Pfizer Inc., Groton, CT, USA
| | - Leela Shrestha
- Centre for Medicines Discovery, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - D Sean Froese
- Centre for Medicines Discovery, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
- Division of Metabolism and Children's Research Center, University Children's Hospital Zürich, University of Zürich, Zürich, Switzerland
| | - Igor M Ferreira
- Centre for Medicines Discovery, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Allison P Berg
- Rare Disease Research Unit, Worldwide Research and Development, Pfizer Inc., Cambridge, MA, USA.
| | - Wyatt W Yue
- Centre for Medicines Discovery, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.
- Biosciences Institute, The Medical School, Newcastle University, Newcastle upon Tyne, UK.
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11
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Triboulet S, N’Gadjaga MD, Niragire B, Köstlbacher S, Horn M, Aimanianda V, Subtil A. CT295 Is Chlamydia trachomatis’ Phosphoglucomutase and a Type 3 Secretion Substrate. Front Cell Infect Microbiol 2022; 12:866729. [PMID: 35795184 PMCID: PMC9251005 DOI: 10.3389/fcimb.2022.866729] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 05/24/2022] [Indexed: 11/13/2022] Open
Abstract
The obligate intracellular bacteria Chlamydia trachomatis store glycogen in the lumen of the vacuoles in which they grow. Glycogen catabolism generates glucose-1-phosphate (Glc1P), while the bacteria can take up only glucose-6-phosphate (Glc6P). We tested whether the conversion of Glc1P into Glc6P could be catalyzed by a phosphoglucomutase (PGM) of host or bacterial origin. We found no evidence for the presence of the host PGM in the vacuole. Two C. trachomatis proteins, CT295 and CT815, are potential PGMs. By reconstituting the reaction using purified proteins, and by complementing PGM deficient fibroblasts, we demonstrated that only CT295 displayed robust PGM activity. Intriguingly, we showed that glycogen accumulation in the lumen of the vacuole of a subset of Chlamydia species (C. trachomatis, C. muridarum, C. suis) correlated with the presence, in CT295 orthologs, of a secretion signal recognized by the type three secretion (T3S) machinery of Shigella. C. caviae and C. pneumoniae do not accumulate glycogen, and their CT295 orthologs lack T3S signals. In conclusion, we established that the conversion of Glc1P into Glc6P was accomplished by a bacterial PGM, through the acquisition of a T3S signal in a “housekeeping” protein. Acquisition of this signal likely contributed to shaping glycogen metabolism within Chlamydiaceae.
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Affiliation(s)
- Sébastien Triboulet
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Unité de Biologie Cellulaire de l’Infection Microbienne, Paris, France
| | - Maimouna D. N’Gadjaga
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Unité de Biologie Cellulaire de l’Infection Microbienne, Paris, France
- Sorbonne Université, Collège Doctoral, Paris, France
| | - Béatrice Niragire
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Unité de Biologie Cellulaire de l’Infection Microbienne, Paris, France
| | - Stephan Köstlbacher
- Centre for Microbiology and Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Matthias Horn
- Centre for Microbiology and Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Vishukumar Aimanianda
- Institut Pasteur, Université Paris Cité, CNRS UMR2000, Unité de Mycologie Moléculaire, Paris, France
| | - Agathe Subtil
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Unité de Biologie Cellulaire de l’Infection Microbienne, Paris, France
- *Correspondence: Agathe Subtil,
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12
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Yang L, Qiu L, Fang Q, Wu S, Ye G. A venom protein of ectoparasitoid Pachycrepoideus vindemiae, PvG6PDH, contributes to parasitism by inhibiting host glucose-6-phosphate metabolism. Insect Sci 2022; 29:399-410. [PMID: 34724344 DOI: 10.1111/1744-7917.12935] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 04/21/2021] [Accepted: 05/05/2021] [Indexed: 05/26/2023]
Abstract
To achieve successful development, female parasitoids, while laying eggs, introduce various virulence factors, mainly venoms, into host insects to manipulate their physiology. Although numerous studies have been conducted to characterize the components of venoms that regulate host immune responses, few systematic investigations have been conducted on the roles of venom proteins in host metabolic regulation. In this investigation, we characterized a novel venom protein in Pachycrepoideus vindemiae called glucose-6-phosphate dehydrogenase (PvG6PDH) and showed it has a vital role in regulating host carbohydrate metabolism. PvG6PDH encodes 510 amino acids and features a signal peptide and two conserved "G6PDH" domains. Multiple sequence alignment showed it has high amino acid identity with G6PDH from other pteromalids, and quantitative polymerase chain reaction analysis and immunofluorescent staining demonstrated a significantly higher expression of PvG6PDH in the venom apparatus compared with the carcass. We report that PvG6PDH contributes to parasitism by inhibiting the glucose-6-phosphate (G6P) metabolism of host Drosophila melanogaster, as demonstrated by PvG6PDH injection and RNA interference analysis. Further tests revealed that the accumulation of host G6P was caused by the transcriptional inhibition of G6P-metabolism-related genes. These findings greatly contribute to our understanding of venom-mediated host metabolic regulation, further laying the foundation for the development of venom proteins as biological agents for pest control.
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Affiliation(s)
- Lei Yang
- Hainan University, Haikou, 570228, China
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Liming Qiu
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Qi Fang
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, 310058, China
| | | | - Gongyin Ye
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, 310058, China
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13
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Wu Z, Wang Z, Zhang K. Isolation and functional characterization of a glucose-6-phosphate/phosphate translocator (IbG6PPT1) from sweet potato (Ipomoea batatas (L.) Lam.). BMC Plant Biol 2021; 21:595. [PMID: 34915842 PMCID: PMC8675480 DOI: 10.1186/s12870-021-03372-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 11/29/2021] [Indexed: 05/05/2023]
Abstract
Sweet potato (Ipomoea batatas (L.) Lam.) is a good source of carbohydrates, an excellent raw material for starch-based industries, and a strong candidate for biofuel production due to its high starch content. However, the molecular basis of starch biosynthesis and accumulation in sweet potato is still insufficiently understood. Glucose-6-phosphate/phosphate translocators (GPTs) mediate the import of glucose-6-phosphate (Glc6P) into plastids for starch synthesis. Here, we report the isolation of a GPT-encoding gene, IbG6PPT1, from sweet potato and the identification of two additional IbG6PPT1 gene copies in the sweet potato genome. IbG6PPT1 encodes a chloroplast membrane-localized GPT belonging to the GPT1 group and highly expressed in storage root of sweet potato. Heterologous expression of IbG6PPT1 resulted in increased starch content in the leaves, root tips, and seeds and soluble sugar in seeds of Arabidopsis thaliana, but a reduction in soluble sugar in the leaves. These findings suggested that IbG6PPT1 might play a critical role in the distribution of carbon sources in source and sink and the accumulation of carbohydrates in storage tissues and would be a good candidate gene for controlling critical starch properties in sweet potato.
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Affiliation(s)
- Zhengdan Wu
- College of Agronomy and Biotechnology, Southwest University, Beibei, Chongqing, 400715, P. R. China
| | - Zhiqian Wang
- College of Agronomy and Biotechnology, Southwest University, Beibei, Chongqing, 400715, P. R. China
| | - Kai Zhang
- College of Agronomy and Biotechnology, Southwest University, Beibei, Chongqing, 400715, P. R. China.
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14
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Zusi C, Rinaldi E, Bonetti S, Boselli ML, Trabetti E, Malerba G, Bonora E, Bonadonna RC, Trombetta M. Haplotypes of the genes (GCK and G6PC2) underlying the glucose/glucose-6-phosphate cycle are associated with pancreatic beta cell glucose sensitivity in patients with newly diagnosed type 2 diabetes from the VNDS study (VNDS 11). J Endocrinol Invest 2021; 44:2567-2574. [PMID: 34128214 DOI: 10.1007/s40618-020-01483-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 12/07/2020] [Indexed: 10/21/2022]
Abstract
BACKGROUND Elevated fasting plasma glucose has been associated with increased risk for development of type 2 diabetes (T2D). The balance between glucokinase (GCK) and glucose-6-phosphate catalytic subunit 2 (G6PC2) activity are involved in glucose homeostasis through glycolytic flux, and subsequent insulin secretion. AIM In this study, we evaluated the association between the genetic variability of G6PC2 and GCK genes and T2D-related quantitative traits. METHODS In 794 drug-naïve, GADA-negative, newly diagnosed T2D patients (VNDS; NTC01526720) we performed: genotyping of 6 independent tag-SNPs within GCK gene and 5 tag-SNPs within G6PC2 gene; euglycaemic insulin clamp to assess insulin sensitivity; OGTT to estimate beta-cell function (derivative and proportional control; DC, PC) by mathematical modeling. Genetic association analysis has been conducted using Plink software. RESULTS Two SNPs within GCK gene (rs882019 and rs1303722) were associated to DC in opposite way (both p < 0.004). Two G6PC2 variants (rs13387347 and rs560887) were associated to both parameters of insulin secretion (DC and PC) and to fasting C-peptide levels (all p < 0.038). Moreover, subjects carrying the A allele of rs560887 showed higher values of 2h-plasma glucose (2hPG) (p = 0.033). Haplotype analysis revealed that GCK (AACAAA) haplotype was associated to decreased fasting C-peptide levels, whereas, the most frequent haplotype of G6PC2 (GGAAG) was associated with higher fasting C-peptide levels (p = 0.001), higher PC (β = 6.87, p = 0.022) and the lower 2hPG (p = 0.012). CONCLUSION Our findings confirmed the role of GCK and G6PC2 in regulating the pulsatility in insulin secretion thereby influencing insulin-signaling and leading to a gradual modulation in glucose levels in Italian patients with newly diagnosed T2D.
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Affiliation(s)
- C Zusi
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University and Hospital Trust of Verona, Piazzale Stefani 1, 37126, Verona, Italy
| | - E Rinaldi
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University and Hospital Trust of Verona, Piazzale Stefani 1, 37126, Verona, Italy
| | - S Bonetti
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University and Hospital Trust of Verona, Piazzale Stefani 1, 37126, Verona, Italy
| | - M L Boselli
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University and Hospital Trust of Verona, Piazzale Stefani 1, 37126, Verona, Italy
| | - E Trabetti
- Department of Neuroscience, Biomedicine and Movement Sciences, Section of Biology and Genetics, University of Verona, Verona, Italy
| | - G Malerba
- Department of Neuroscience, Biomedicine and Movement Sciences, Section of Biology and Genetics, University of Verona, Verona, Italy
| | - E Bonora
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University and Hospital Trust of Verona, Piazzale Stefani 1, 37126, Verona, Italy
| | - R C Bonadonna
- Department of Medicine and Surgery, University of Parma, Parma, Italy
- Division of Endocrinology and Metabolic Diseases, Azienda Ospedaliero-Universitaria di Parma, Parma, Italy
| | - M Trombetta
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University and Hospital Trust of Verona, Piazzale Stefani 1, 37126, Verona, Italy.
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15
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Ghosh P, Barman A, Das Gupta SK. Induced expression of the zwf gene in the presence of glucose contributes to lowering of glucose 6-phosphate level and consequently reduction of growth rate of Mycobacterium smegmatis. Microbiology (Reading) 2021; 167. [PMID: 34236958 DOI: 10.1099/mic.0.001067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In Mycobacterium smegmatis (renamed Mycolicibacterium smegmatis), glucose 6-phosphate (G6P) level is exceptionally high as compared to other bacteria, E. coli for example. Earlier investigations have indicated that G6P protects M. smegmatis (Msm) against oxidative stress-inducing agents. G6P is a glycolytic intermediate formed either directly through the phosphorylation of glucose or indirectly via the gluconeogenic pathway. Its consumption is catalysed by several enzymes, one of which being the NADPH dependent G6P dehydrogenase (G6PDH) encoded by zwf (msmeg_0314). While investigating the extent to which the carbon sources glucose and glycerol influence Msm growth, we observed that intracellular concentration of G6P was lower in the former's presence than the latter. We could correlate this difference with that in the growth rate, which was higher in glycerol than glucose. We also found that lowering of G6P content in glucose-grown cells was triggered by the induced expression of zwf and the resultant increase in G6PDH activity. When we silenced zwf using CRISPR-Cas9 technology, we observed a significant rise in the growth rate of Msm. Therefore, we have found that depletion of G6P in glucose-grown cells due to increased G6PDH activity is at least one reason why the growth rate of Msm in glucose is less than glycerol. However, we could not establish a similar link-up between slow growth in glucose and lowering of G6P level in the case of Mycobacterium tuberculosis (Mtb). Mycobacteria, therefore, may have evolved diverse mechanisms to ensure that they use glycerol preferentially over glucose for their growth.
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Affiliation(s)
- Poulami Ghosh
- Department of Microbiology, Bose Institute, P-1/12 C.I.T. Scheme VIIM, Kolkata-700054, India
| | - Anik Barman
- Department of Microbiology, Bose Institute, P-1/12 C.I.T. Scheme VIIM, Kolkata-700054, India
| | - Sujoy K Das Gupta
- Department of Microbiology, Bose Institute, P-1/12 C.I.T. Scheme VIIM, Kolkata-700054, India
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16
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Babu SN, Govindarajan S, Vijayalakshmi MA, Noor A. Role of zonulin and GLP-1/DPP-IV in alleviation of diabetes mellitus by peptide/polypeptide fraction of Aloe vera in streptozotocin- induced diabetic wistar rats. J Ethnopharmacol 2021; 272:113949. [PMID: 33610707 DOI: 10.1016/j.jep.2021.113949] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 02/09/2021] [Accepted: 02/14/2021] [Indexed: 06/12/2023]
Abstract
ETHNO-PHARMACOLOGICAL RELEVANCE The genus Aloe has a long history of usage in medicine. Aloe barbadensis Miller, commonly known as Aloe vera, is said to possess anti-diabetic, anti-inflammatory, anti-cancer, anti-microbial, immunomodulation, wound healing properties. AIM OF THE STUDY In diabetes mellitus, loss in intestinal permeability is observed with high levels of zonulin and low levels of glucagon-like peptide-1 (GLP-1) leading to hyperglycemia. The aim of the study was to understand the role of peptide/polypeptide fraction (PPF) of Aloe vera in the alleviation of diabetes through maintaining the intestinal permeability by regulating the zonulin and GLP-1 levels. MATERIALS AND METHODS The PPF of Aloe vera was obtained through trichloroacetic acid precipitation. The anti-diabetic potential of the PPF was tested through DPP-IV inhibition, glucose diffusion assay, and by using Rin-m5F cells. The anti-diabetic potential of the PPF was tested at a dose of 0.450 mg/kg bw in vivo using streptozotocin-induced diabetic Wistar rats. The effect of PPF on fasting plasma glucose, insulin, glucagon, Zonulin, GLP-1, DPP-IV, levels were studied in diabetic rats. The histopathological studies of the pancreas, small intestine, and liver were carried out for organ-specific effects. RESULTS PPF has the ability to reduce fasting plasma glucose levels with concomitant increase in insulin levels in streptozotocin-induced diabetic rats. It was also observed that increase in GLP-1 levels with a decrease in DPP-IV and zonulin levels thereby mitigating the loss of intestinal permeability. These findings correlate with the small intestine's histopathological observation where the excessive proliferation of epithelium in the small intestine of diabetic rats was reduced after PPF treatment. CONCLUSION These results suggest that the PPF of Aloe vera alleviates diabetes through islet cell rejuvenation via GLP-1/DPP-IV pathway and thereby suggesting the usage of PPF as an alternate medicine for diabetes mellitus with the possibility to reduce the intestinal permeability and zonulin levels.
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Affiliation(s)
- Spoorthy N Babu
- Centre for Bioseparation Technology, Vellore Institute of Technology, Vellore, 632014, India
| | - S Govindarajan
- Centre for Bioseparation Technology, Vellore Institute of Technology, Vellore, 632014, India
| | - M A Vijayalakshmi
- Centre for Bioseparation Technology, Vellore Institute of Technology, Vellore, 632014, India
| | - Ayesha Noor
- Centre for Bioseparation Technology, Vellore Institute of Technology, Vellore, 632014, India.
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Massey V, Parrish A, Argemi J, Moreno M, Mello A, García-Rocha M, Altamirano J, Odena G, Dubuquoy L, Louvet A, Martinez C, Adrover A, Affò S, Morales-Ibanez O, Sancho-Bru P, Millán C, Alvarado-Tapias E, Morales-Arraez D, Caballería J, Mann J, Cao S, Sun Z, Shah V, Cameron A, Mathurin P, Snider N, Villanueva C, Morgan TR, Guinovart J, Vadigepalli R, Bataller R. Integrated Multiomics Reveals Glucose Use Reprogramming and Identifies a Novel Hexokinase in Alcoholic Hepatitis. Gastroenterology 2021; 160:1725-1740.e2. [PMID: 33309778 PMCID: PMC8613537 DOI: 10.1053/j.gastro.2020.12.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 11/06/2020] [Accepted: 12/01/2020] [Indexed: 02/02/2023]
Abstract
BACKGROUND & AIMS We recently showed that alcoholic hepatitis (AH) is characterized by dedifferentiation of hepatocytes and loss of mature functions. Glucose metabolism is tightly regulated in healthy hepatocytes. We hypothesize that AH may lead to metabolic reprogramming of the liver, including dysregulation of glucose metabolism. METHODS We performed integrated metabolomic and transcriptomic analyses of liver tissue from patients with AH or alcoholic cirrhosis or normal liver tissue from hepatic resection. Focused analyses of chromatin immunoprecipitation coupled to DNA sequencing was performed. Functional in vitro studies were performed in primary rat and human hepatocytes and HepG2 cells. RESULTS Patients with AH exhibited specific changes in the levels of intermediates of glycolysis/gluconeogenesis, the tricarboxylic acid cycle, and monosaccharide and disaccharide metabolism. Integrated analysis of the transcriptome and metabolome showed the used of alternate energetic pathways, metabolite sinks and bottlenecks, and dysregulated glucose storage in patients with AH. Among genes involved in glucose metabolism, hexokinase domain containing 1 (HKDC1) was identified as the most up-regulated kinase in patients with AH. Histone active promoter and enhancer markers were increased in the HKDC1 genomic region. High HKDC1 levels were associated with the development of acute kidney injury and decreased survival. Increased HKDC1 activity contributed to the accumulation of glucose-6-P and glycogen in primary rat hepatocytes. CONCLUSIONS Altered metabolite levels and messenger RNA expression of metabolic enzymes suggest the existence of extensive reprogramming of glucose metabolism in AH. Increased HKDC1 expression may contribute to dysregulated glucose metabolism and represents a novel biomarker and therapeutic target for AH.
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Affiliation(s)
- Veronica Massey
- Division of Gastroenterology and Hepatology, Departments of Medicine and Nutrition, and Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, North Carolina
| | - Austin Parrish
- Daniel Baugh Institute, Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Josepmaria Argemi
- Department of Gastroenterology and Hepatology, Division of Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania; Liver Unit, Clinica Universidad de Navarra. Hepatology Program, Center for Applied Medical Research, IdisNA, Pamplona, Spain
| | - Montserrat Moreno
- Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
| | - Aline Mello
- Department of Gastroenterology and Hepatology, Division of Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Mar García-Rocha
- Institute for Research in Biomedicine, Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Jose Altamirano
- Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain; Liver Unit, Internal Medicine Department, Hospital Universitari Vall d'Hebrón, Vall d'Hebrón Institut de Recerca, Barcelona, Spain
| | - Gemma Odena
- Division of Gastroenterology and Hepatology, Departments of Medicine and Nutrition, and Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, North Carolina
| | - Laurent Dubuquoy
- Service des Maladies de l'appareil digestif, CHU Lille, Inserm LIRIC-UMR995, University of Lille, Lille, France
| | - Alexandre Louvet
- Service des Maladies de l'appareil digestif, CHU Lille, Inserm LIRIC-UMR995, University of Lille, Lille, France
| | - Carlos Martinez
- Institute for Research in Biomedicine, Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Anna Adrover
- Institute for Research in Biomedicine, Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Silvia Affò
- Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
| | | | - Pau Sancho-Bru
- Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
| | - Cristina Millán
- Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
| | - Edilmar Alvarado-Tapias
- Department of Gastroenterology, Hospital Santa Creu i Sant Pau, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas, Instituto de Salud Carlos III, Madrid, Spain
| | - Dalia Morales-Arraez
- Department of Gastroenterology and Hepatology, Division of Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Juan Caballería
- Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain; Liver Unit, Hospital Clínic, CIBER de Enfermedades Hepáticas y Digestivas, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain
| | - Jelena Mann
- Newcastle Fibrosis Research Group, Institute of Cellular Medicine, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne, United Kingdom
| | - Sheng Cao
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota
| | - Zhaoli Sun
- Johns Hopkins School of Medicine, Department of Surgery and Transplant Biology Research Center, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Vijay Shah
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota
| | - Andrew Cameron
- Johns Hopkins School of Medicine, Department of Surgery and Transplant Biology Research Center, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Phillipe Mathurin
- Service des Maladies de l'appareil digestif, CHU Lille, Inserm LIRIC-UMR995, University of Lille, Lille, France
| | - Natasha Snider
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina
| | - Càndid Villanueva
- Department of Gastroenterology, Hospital Santa Creu i Sant Pau, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas, Instituto de Salud Carlos III, Madrid, Spain; Institut de Recerca, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain; Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), Barcelona, Spain
| | - Timothy R Morgan
- Gastroenterology Services, VA Long Beach Healthcare, VA Long Beach Healthcare System, Long Beach, California
| | - Joan Guinovart
- Institute for Research in Biomedicine, Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Rajanikanth Vadigepalli
- Daniel Baugh Institute, Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Ramon Bataller
- Division of Gastroenterology and Hepatology, Departments of Medicine and Nutrition, and Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, North Carolina; Department of Gastroenterology and Hepatology, Division of Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania.
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18
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Coelho M, Barosa C, Tavares L, Jones JG. Metabolic incorporation of H 218 O into specific glucose-6-phosphate oxygens by red-blood-cell lysates as observed by 13 C isotope-shifted NMR signals. NMR Biomed 2020; 33:e4395. [PMID: 32789995 DOI: 10.1002/nbm.4395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 07/24/2020] [Accepted: 07/25/2020] [Indexed: 06/11/2023]
Abstract
Water enriched with oxygen-18 (H218 O) is a potential tracer for evaluating the sources of glucose and glycogen synthesis since it is incorporated into specific sites of glucose-6-phosphate via specific enzyme-mediated exchange/addition mechanisms. Unlike 2 H, 18 O does not experience significant isotope effects for any of these processes. Therefore, H218 O might provide more precise estimates of endogenous carbohydrate synthesis compared with deuterated water provided that positional 18 O enrichments of glucose can be measured. As a proof of concept, H218 O was incorporated into a well characterized hemolysate model of sugar phosphate metabolism and 13 C NMR was applied to quantify positional 18 O enrichment of glucose-6-phosphate oxygens. Human erythrocyte hemolysate preparations were incubated overnight at 37 °C with a buffer containing sugar phosphate precursors and 20% (n = 5) and 80% (n = 1) H218 O. Enrichment of glucose-6-phosphate was analyzed by 13 C NMR analysis of 18 O-shifted versus unshifted signals following derivatization to monoacetone glucose (MAG). 13 C NMR MAG spectra from hemolysate revealed resolved 18 O-shifted signals in Positions 1-5. Mean 18 O enrichments were 16.4 ± 1.6% (Position 1), 13.3 ± 1.3% (Position 2), 4.1 ± 1.1% (Position 3), 12.6 ± 0.8% (Position 4), 10.7 ± 1.4% (Position 5), and no detectable enrichment of Position 6. No 18 O-shifted glucose-6-phosphate signals were detected in preparations containing sugar phosphate precursors only. H218 O is incorporated into Positions 1-5 of glucose-6-phosphate in accordance with spontaneous aldose hydration and specific enzymatic reaction mechanisms. This provides a basis for its deployment as a tracer for glucose and glycogen biosynthesis.
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Affiliation(s)
- Margarida Coelho
- Center for Neurosciences and Cell Biology, University of Coimbra, Portugal
- Chemistry Department, Faculty of Sciences and Technology, University of Coimbra, Portugal
| | - Cristina Barosa
- Center for Neurosciences and Cell Biology, University of Coimbra, Portugal
| | - Ludgero Tavares
- Center for Neurosciences and Cell Biology, University of Coimbra, Portugal
| | - John G Jones
- Center for Neurosciences and Cell Biology, University of Coimbra, Portugal
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19
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Chadee A, Vanlerberghe GC. Distinctive mitochondrial and chloroplast components contributing to the maintenance of carbon balance during plant growth at elevated CO 2. Plant Signal Behav 2020; 15:1795395. [PMID: 32705929 PMCID: PMC8550537 DOI: 10.1080/15592324.2020.1795395] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Plant carbon balance depends upon the difference between photosynthetic carbon gain and respiratory carbon loss. In C3 plants, growth at an elevated atmospheric concentration of CO2 (ECO2) stimulates photosynthesis and raises the leaf carbohydrate status, but how respiration responds is less understood. In this study, growth of Nicotiana tabacum at ECO2 increased the protein amount of the non-energy conserving mitochondrial alternative oxidase (AOX). Growth at ECO2 increased AOX1a transcript amount, and the transcript amount of a putative sugar-responsive gene encoding a chloroplast glucose-6-phosphate/phosphate translocator (GPT3). We suggest that the elevated amounts of AOX and GPT3 represent distinctive mitochondrial and chloroplast mechanisms to manage an excessive cytosolic pool of sugar phosphates. AOX respiration could consume cytosolic sugar phosphates, without this activity being restricted by rates of ATP turnover. GPT3 could allow accumulating cytosolic glucose-6-phosphate to return to the chloroplast. This could feed starch synthesis or a glucose-6-phosphate shunt in the Calvin cycle. AOX and GPT3 activities could buffer against Pi depletions that might otherwise disrupt mitochondrial and chloroplast electron transport chain activities. AOX and GPT3 activities could also buffer against a down-regulation of photosynthetic capacity by preventing a persistent imbalance between photosynthetic carbon gain and the activity of carbon utilizing sinks.
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Affiliation(s)
- Avesh Chadee
- Department of Biological Sciences and Department of Cell and Systems Biology, University of Toronto Scarborough, Toronto, ON, Canada
| | - Greg C. Vanlerberghe
- Department of Biological Sciences and Department of Cell and Systems Biology, University of Toronto Scarborough, Toronto, ON, Canada
- CONTACT Greg C. Vanlerberghe Department of Biological Sciences and Department of Cell and Systems Biology, University of Toronto Scarborough, Toronto, ONM1C1A4, Canada
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20
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Tran KN, Jang SH, Lee C. Effect of active-site aromatic residues Tyr or Phe on activity and stability of glucose 6-phosphate dehydrogenase from psychrophilic Arctic bacterium Sphingomonas sp. Biochim Biophys Acta Proteins Proteom 2020; 1869:140543. [PMID: 32966894 DOI: 10.1016/j.bbapap.2020.140543] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 09/14/2020] [Accepted: 09/17/2020] [Indexed: 11/18/2022]
Abstract
Cold-adapted enzymes maintain correct conformation at their active sites despite their intrinsically flexible structures. The psychrophilic Arctic bacterium Sphingomonas sp. PAMC 26621 has two glucose 6-phosphate dehydrogenase (G6PD) isozymes, SpG6PD1 involved in the Entner-Doudoroff pathway and SpG6PD2 in the oxidative pentose phosphate pathway. Structural modeling of SpG6PD1 showed that the hydroxyl group of Tyr177 participates in substrate binding by forming a hydrogen bond with the phosphate group of glucose 6-phosphate, whereas in SpG6PD2, a Phe residue is present in the corresponding position of Tyr177. In this study, we investigated how subtle differences in aromatic residues in the substrate-binding pocket of SpG6PD1 affect enzymatic activity and stability. Mutations of Tyr177 to Ala, His, Phe, and Trp caused increases in the rigidity of the SpG6PD1 structure. Particularly, mutants Y177F and Y177W showed increased thermal stabilities compared to wild-type (WT) but 3- and 15-fold lower catalytic efficiencies, respectively. However, mutants Y177A and Y177H became heat-labile at moderate temperatures. These results indicate that an aromatic residue (Tyr or Phe) is necessary for the substrate-binding pocket of SpG6PD1; Tyr with its hydroxyl group is preferred for enzymatic activity, whereas the more hydrophobic Phe is preferred for thermal stability. Substitutions of bulky Trp for Tyr or Phe at this position resulted in substantial loss of activity. Our study suggests that delicate adjustment of aromatic residues can regulate the activity and stability of psychrophilic G6PD isozymes involved in different metabolic pathways.
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Affiliation(s)
- Kiet N Tran
- Department of Biomedical Science and Center for Bio-Nanomaterials, Daegu University, Gyeongsan 38453, South Korea
| | - Sei-Heon Jang
- Department of Biomedical Science and Center for Bio-Nanomaterials, Daegu University, Gyeongsan 38453, South Korea
| | - ChangWoo Lee
- Department of Biomedical Science and Center for Bio-Nanomaterials, Daegu University, Gyeongsan 38453, South Korea.
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21
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Farrash W, Brook M, Crossland H, Phillips BE, Cegielski J, Wilkinson DJ, Constantin-Teodosiu D, Greenhaff PL, Smith K, Cleasby M, Atherton PJ. Impacts of rat hindlimb Fndc5/irisin overexpression on muscle and adipose tissue metabolism. Am J Physiol Endocrinol Metab 2020; 318:E943-E955. [PMID: 32369414 PMCID: PMC7311674 DOI: 10.1152/ajpendo.00034.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Myokines, such as irisin, have been purported to exert physiological effects on skeletal muscle in an autocrine/paracrine fashion. In this study, we aimed to investigate the mechanistic role of in vivo fibronectin type III domain-containing 5 (Fndc5)/irisin upregulation in muscle. Overexpression (OE) of Fndc5 in rat hindlimb muscle was achieved by in vivo electrotransfer, i.e., bilateral injections of Fndc5 harboring vectors for OE rats (n = 8) and empty vector for control rats (n = 8). Seven days later, a bolus of D2O (7.2 mL/kg) was administered via oral gavage to quantify muscle protein synthesis. After an overnight fast, on day 9, 2-deoxy-d-glucose-6-phosphate (2-DG6P; 6 mg/kg) was provided during an intraperitoneal glucose tolerance test (2 g/kg) to assess glucose handling. Animals were euthanized, musculus tibialis cranialis muscles and subcutaneous fat (inguinal) were harvested, and metabolic and molecular effects were evaluated. Muscle Fndc5 mRNA increased with OE (~2-fold; P = 0.014), leading to increased circulating irisin (1.5 ± 0.9 to 3.5 ± 1.2 ng/mL; P = 0.049). OE had no effect on protein anabolism or mitochondrial biogenesis; however, muscle glycogen was increased, along with glycogen synthase 1 gene expression (P = 0.04 and 0.02, respectively). In addition to an increase in glycogen synthase activation in OE (P = 0.03), there was a tendency toward increased glucose transporter 4 protein (P = 0.09). However, glucose uptake (accumulation of 2-DG6P) was identical. Irisin elicited no endocrine effect on mitochondrial biogenesis or uncoupling proteins in white adipose tissue. Hindlimb overexpression led to physiological increases in Fndc5/irisin. However, our data indicate limited short-term impacts of irisin in relation to muscle anabolism, mitochondrial biogenesis, glucose uptake, or adipose remodeling.
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Affiliation(s)
- W Farrash
- Medical Research Council Versus Arthritis Centre for Musculoskeletal Ageing Research and Nottingham National Institute for Health Research Biomedical Research Centre, School of Medicine, University of Nottingham, Derby, United Kingdom
- College of Applied Medical Sciences, Umm Al-Qura University, Makkah, Saudi Arabia
| | - M Brook
- Medical Research Council Versus Arthritis Centre for Musculoskeletal Ageing Research and Nottingham National Institute for Health Research Biomedical Research Centre, School of Medicine, University of Nottingham, Derby, United Kingdom
| | - H Crossland
- Medical Research Council Versus Arthritis Centre for Musculoskeletal Ageing Research and Nottingham National Institute for Health Research Biomedical Research Centre, School of Medicine, University of Nottingham, Derby, United Kingdom
| | - B E Phillips
- Medical Research Council Versus Arthritis Centre for Musculoskeletal Ageing Research and Nottingham National Institute for Health Research Biomedical Research Centre, School of Medicine, University of Nottingham, Derby, United Kingdom
| | - J Cegielski
- Medical Research Council Versus Arthritis Centre for Musculoskeletal Ageing Research and Nottingham National Institute for Health Research Biomedical Research Centre, School of Medicine, University of Nottingham, Derby, United Kingdom
| | - D J Wilkinson
- Medical Research Council Versus Arthritis Centre for Musculoskeletal Ageing Research and Nottingham National Institute for Health Research Biomedical Research Centre, School of Medicine, University of Nottingham, Derby, United Kingdom
| | - D Constantin-Teodosiu
- Medical Research Council Versus Arthritis Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - P L Greenhaff
- Medical Research Council Versus Arthritis Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - K Smith
- Medical Research Council Versus Arthritis Centre for Musculoskeletal Ageing Research and Nottingham National Institute for Health Research Biomedical Research Centre, School of Medicine, University of Nottingham, Derby, United Kingdom
| | - M Cleasby
- Molecular Physiology of Diabetes Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, University of London, London, United Kingdom
| | - P J Atherton
- Medical Research Council Versus Arthritis Centre for Musculoskeletal Ageing Research and Nottingham National Institute for Health Research Biomedical Research Centre, School of Medicine, University of Nottingham, Derby, United Kingdom
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22
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Baune MC, Lansing H, Fischer K, Meyer T, Charton L, Linka N, von Schaewen A. The Arabidopsis Plastidial Glucose-6-Phosphate Transporter GPT1 is Dually Targeted to Peroxisomes via the Endoplasmic Reticulum. Plant Cell 2020; 32:1703-1726. [PMID: 32111666 PMCID: PMC7203913 DOI: 10.1105/tpc.19.00959] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 01/28/2020] [Accepted: 02/28/2020] [Indexed: 05/22/2023]
Abstract
Studies on Glucose-6-phosphate (G6P)/phosphate translocator isoforms GPT1 and GPT2 reported the viability of Arabidopsis (Arabidopsis thaliana) gpt2 mutants, whereas heterozygous gpt1 mutants exhibited a variety of defects during fertilization/seed set, indicating that GPT1 is essential for this process. Among other functions, GPT1 was shown to be important for pollen and embryo-sac development. Because our previous work on the irreversible part of the oxidative pentose phosphate pathway (OPPP) revealed comparable effects, we investigated whether GPT1 may dually localize to plastids and peroxisomes. In reporter fusions, GPT2 localized to plastids, but GPT1 also localized to the endoplasmic reticulum (ER) and around peroxisomes. GPT1 contacted two oxidoreductases and also peroxins that mediate import of peroxisomal membrane proteins from the ER, hinting at dual localization. Reconstitution in yeast (Saccharomyces cerevisiae) proteoliposomes revealed that GPT1 preferentially exchanges G6P for ribulose-5-phosphate (Ru5P). Complementation analyses of heterozygous +/gpt1 plants demonstrated that GPT2 is unable to compensate for GPT1 in plastids, whereas GPT1 without the transit peptide (enforcing ER/peroxisomal localization) increased gpt1 transmission significantly. Because OPPP activity in peroxisomes is essential for fertilization, and immunoblot analyses hinted at the presence of unprocessed GPT1-specific bands, our findings suggest that GPT1 is indispensable in both plastids and peroxisomes. Together with its G6P-Ru5P exchange preference, GPT1 appears to play a role distinct from that of GPT2 due to dual targeting.
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Affiliation(s)
- Marie-Christin Baune
- Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Hannes Lansing
- Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Kerstin Fischer
- Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Tanja Meyer
- Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Lennart Charton
- Biochemie der Pflanzen, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
| | - Nicole Linka
- Biochemie der Pflanzen, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
| | - Antje von Schaewen
- Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
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23
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Monticelli M, Liguori L, Allocca M, Andreotti G, Cubellis MV. β-Glucose-1,6-Bisphosphate Stabilizes Pathological Phophomannomutase2 Mutants In Vitro and Represents a Lead Compound to Develop Pharmacological Chaperones for the Most Common Disorder of Glycosylation, PMM2-CDG. Int J Mol Sci 2019; 20:E4164. [PMID: 31454904 PMCID: PMC6747070 DOI: 10.3390/ijms20174164] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 08/13/2019] [Accepted: 08/22/2019] [Indexed: 12/13/2022] Open
Abstract
A large number of mutations causing PMM2-CDG, which is the most frequent disorder of glycosylation, destabilize phosphomannomutase2. We looked for a pharmacological chaperone to cure PMM2-CDG, starting from the structure of a natural ligand of phosphomannomutase2, α-glucose-1,6-bisphosphate. The compound, β-glucose-1,6-bisphosphate, was synthesized and characterized via 31P-NMR. β-glucose-1,6-bisphosphate binds its target enzyme in silico. The binding induces a large conformational change that was predicted by the program PELE and validated in vitro by limited proteolysis. The ability of the compound to stabilize wild type phosphomannomutase2, as well as frequently encountered pathogenic mutants, was measured using thermal shift assay. β-glucose-1,6-bisphosphate is relatively resistant to the enzyme that specifically hydrolyses natural esose-bisphosphates.
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Affiliation(s)
- Maria Monticelli
- Dipartimento di Biologia, Università Federico II, 80126 Napoli, Italy
| | - Ludovica Liguori
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania "Luigi Vanvitelli", 81100 Caserta, Italy
- Istituto di Chimica Biomolecolare-CNR, 80078 Pozzuoli, Italy
| | - Mariateresa Allocca
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania "Luigi Vanvitelli", 81100 Caserta, Italy
- Istituto di Chimica Biomolecolare-CNR, 80078 Pozzuoli, Italy
| | | | - Maria Vittoria Cubellis
- Dipartimento di Biologia, Università Federico II, 80126 Napoli, Italy
- Istituto di Chimica Biomolecolare-CNR, 80078 Pozzuoli, Italy
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24
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Veras HCT, Campos CG, Nascimento IF, Abdelnur PV, Almeida JRM, Parachin NS. Metabolic flux analysis for metabolome data validation of naturally xylose-fermenting yeasts. BMC Biotechnol 2019; 19:58. [PMID: 31382948 PMCID: PMC6683545 DOI: 10.1186/s12896-019-0548-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 07/19/2019] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Efficient xylose fermentation still demands knowledge regarding xylose catabolism. In this study, metabolic flux analysis (MFA) and metabolomics were used to improve our understanding of xylose metabolism. Thus, a stoichiometric model was constructed to simulate the intracellular carbon flux and used to validate the metabolome data collected within xylose catabolic pathways of non-Saccharomyces xylose utilizing yeasts. RESULTS A metabolic flux model was constructed using xylose fermentation data from yeasts Scheffersomyces stipitis, Spathaspora arborariae, and Spathaspora passalidarum. In total, 39 intracellular metabolic reactions rates were utilized validating the measurements of 11 intracellular metabolites, acquired by mass spectrometry. Among them, 80% of total metabolites were confirmed with a correlation above 90% when compared to the stoichiometric model. Among the intracellular metabolites, fructose-6-phosphate, glucose-6-phosphate, ribulose-5-phosphate, and malate are validated in the three studied yeasts. However, the metabolites phosphoenolpyruvate and pyruvate could not be confirmed in any yeast. Finally, the three yeasts had the metabolic fluxes from xylose to ethanol compared. Xylose catabolism occurs at twice-higher flux rates in S. stipitis than S. passalidarum and S. arborariae. Besides, S. passalidarum present 1.5 times high flux rate in the xylose reductase reaction NADH-dependent than other two yeasts. CONCLUSIONS This study demonstrated a novel strategy for metabolome data validation and brought insights about naturally xylose-fermenting yeasts. S. stipitis and S. passalidarum showed respectively three and twice higher flux rates of XR with NADH cofactor, reducing the xylitol production when compared to S. arborariae. Besides then, the higher flux rates directed to pentose phosphate pathway (PPP) and glycolysis pathways resulted in better ethanol production in S. stipitis and S. passalidarum when compared to S. arborariae.
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Affiliation(s)
- Henrique C. T. Veras
- Grupo Engenharia de Biocatalisadores, Universidade de Brasília - UnB , Campus Darcy Ribeiro, Instituto de Ciências Biológicas, Bloco K, 1° andar, Asa Norte, Brasilia, 70.790-900 Brazil
- Empresa Brasileira de Pesquisa Agropecuária, EMBRAPA Agroenergia, Brasília-DF, Brazil
| | - Christiane G. Campos
- Empresa Brasileira de Pesquisa Agropecuária, EMBRAPA Agroenergia, Brasília-DF, Brazil
- Instituto de Química, Universidade Federal de Goiás - UFG, Goiânia, Brazil
| | - Igor F. Nascimento
- Programa de Pós-Graduação em Administração, Universidade de Brasília - UnB, Brasília, Brazil
| | - Patrícia V. Abdelnur
- Empresa Brasileira de Pesquisa Agropecuária, EMBRAPA Agroenergia, Brasília-DF, Brazil
- Instituto de Química, Universidade Federal de Goiás - UFG, Goiânia, Brazil
| | - João R. M. Almeida
- Empresa Brasileira de Pesquisa Agropecuária, EMBRAPA Agroenergia, Brasília-DF, Brazil
- Programa de Pós-Graduação em Biologia Microbiana, Instituto de Biologia, Universidade de Brasília - UnB, Brasilia, Brazil
| | - Nádia S. Parachin
- Grupo Engenharia de Biocatalisadores, Universidade de Brasília - UnB , Campus Darcy Ribeiro, Instituto de Ciências Biológicas, Bloco K, 1° andar, Asa Norte, Brasilia, 70.790-900 Brazil
- Programa de Pós-Graduação em Biologia Microbiana, Instituto de Biologia, Universidade de Brasília - UnB, Brasilia, Brazil
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25
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Kjøbsted R, Roll JLW, Jørgensen NO, Birk JB, Foretz M, Viollet B, Chadt A, Al-Hasani H, Wojtaszewski JFP. AMPK and TBC1D1 Regulate Muscle Glucose Uptake After, but Not During, Exercise and Contraction. Diabetes 2019; 68:1427-1440. [PMID: 31010958 DOI: 10.2337/db19-0050] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 04/12/2019] [Indexed: 11/13/2022]
Abstract
Exercise increases glucose uptake in skeletal muscle independently of insulin signaling. This makes exercise an effective stimulus to increase glucose uptake in insulin-resistant skeletal muscle. AMPK has been suggested to regulate muscle glucose uptake during exercise/contraction, but findings from studies of various AMPK transgenic animals have not reached consensus on this matter. Comparing methods used in these studies reveals a hitherto unappreciated difference between those studies reporting a role of AMPK and those that do not. This led us to test the hypothesis that AMPK and downstream target TBC1D1 are involved in regulating muscle glucose uptake in the immediate period after exercise/contraction but not during exercise/contraction. Here we demonstrate that glucose uptake during exercise/contraction was not compromised in AMPK-deficient skeletal muscle, whereas reversal of glucose uptake toward resting levels after exercise/contraction was markedly faster in AMPK-deficient muscle compared with wild-type muscle. Moreover, muscle glucose uptake after contraction was positively associated with phosphorylation of TBC1D1, and skeletal muscle from TBC1D1-deficient mice displayed impaired glucose uptake after contraction. These findings reconcile previous observed discrepancies and redefine the role of AMPK activation during exercise/contraction as being important for maintaining glucose permeability in skeletal muscle in the period after, but not during, exercise/contraction.
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Affiliation(s)
- Rasmus Kjøbsted
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Julie L W Roll
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Nicolas O Jørgensen
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Jesper B Birk
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Marc Foretz
- INSERM, U1016, Institut Cochin, Paris, France
- Centre National de la Recherche Scientifique (CNRS), UMR8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Benoit Viollet
- INSERM, U1016, Institut Cochin, Paris, France
- Centre National de la Recherche Scientifique (CNRS), UMR8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Alexandra Chadt
- German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University Düsseldorf, Medical Faculty, Düsseldorf, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
| | - Hadi Al-Hasani
- German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University Düsseldorf, Medical Faculty, Düsseldorf, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
| | - Jørgen F P Wojtaszewski
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
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26
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Li J, Weraduwage SM, Preiser AL, Tietz S, Weise SE, Strand DD, Froehlich JE, Kramer DM, Hu J, Sharkey TD. A Cytosolic Bypass and G6P Shunt in Plants Lacking Peroxisomal Hydroxypyruvate Reductase. Plant Physiol 2019; 180:783-792. [PMID: 30886114 PMCID: PMC6548278 DOI: 10.1104/pp.19.00256] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 03/11/2019] [Indexed: 05/18/2023]
Abstract
The oxygenation of ribulose 1,5-bisphosphate by Rubisco is the first step in photorespiration and reduces the efficiency of photosynthesis in C3 plants. Our recent data indicate that mutants in photorespiration have increased rates of photosynthetic cyclic electron flow around photosystem I. We investigated mutant lines lacking peroxisomal hydroxypyruvate reductase to determine if there are connections between 2-phosphoglycolate accumulation and cyclic electron flow in Arabidopsis (Arabidopsis thaliana). We found that 2-phosphoglycolate is a competitive inhibitor of triose phosphate isomerase, an enzyme in the Calvin-Benson cycle that converts glyceraldehyde 3-phosphate to dihydroxyacetone phosphate. This block in metabolism could be overcome if glyceraldehyde 3-phosphate is exported to the cytosol, where cytosolic triose phosphate isomerase could convert it to dihydroxyacetone phosphate. We found evidence that carbon is reimported as glucose-6-phosphate, forming a cytosolic bypass around the block of stromal triose phosphate isomerase. However, this also stimulates a glucose-6-phosphate shunt, which consumes ATP, which can be compensated by higher rates of cyclic electron flow.
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Affiliation(s)
- Jiying Li
- Michigan State University-Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824
| | - Sarathi M Weraduwage
- Michigan State University-Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824
| | - Alyssa L Preiser
- Michigan State University-Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824
| | - Stefanie Tietz
- Michigan State University-Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824
| | - Sean E Weise
- Michigan State University-Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Deserah D Strand
- Michigan State University-Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824
| | - John E Froehlich
- Michigan State University-Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - David M Kramer
- Michigan State University-Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Jianping Hu
- Michigan State University-Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824
| | - Thomas D Sharkey
- Michigan State University-Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
- Plant Resilience Institute, Michigan State University, East Lansing, Michigan 48824
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27
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Dumschott K, Dechorgnat J, Merchant A. Water Deficit Elicits a Transcriptional Response of Genes Governing d-pinitol Biosynthesis in Soybean ( Glycine max). Int J Mol Sci 2019; 20:E2411. [PMID: 31096655 PMCID: PMC6566849 DOI: 10.3390/ijms20102411] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 05/08/2019] [Indexed: 11/16/2022] Open
Abstract
d-pinitol is the most commonly accumulated sugar alcohol in the Leguminosae family and has been observed to increase significantly in response to abiotic stress. While previous studies have identified genes involved in d-pinitol synthesis, no study has investigated transcript expression in planta. The present study quantified the expression of several genes involved in d-pinitol synthesis in different plant tissues and investigated the accumulation of d-pinitol, myo-inositol and other metabolites in response to a progressive soil drought in soybean (Glycine max). Expression of myo-inositol 1-phosphate synthase (INPS), the gene responsible for the conversion of glucose-6-phosphate to myo-inositol-1-phosphate, was significantly up regulated in response to a water deficit for the first two sampling weeks. Expression of myo-inositol O-methyl transferase (IMT1), the gene responsible for the conversion of myo-inositol into d-ononitol was only up regulated in stems at sampling week 3. Assessment of metabolites showed significant changes in their concentration in leaves and stems. d-Pinitol concentration was significantly higher in all organs sampled from water deficit plants for all three sampling weeks. In contrast, myo-inositol, had significantly lower concentrations in leaf samples despite up regulation of INPS suggesting the transcriptionally regulated flux of carbon through the myo-inositol pool is important during water deficit.
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Affiliation(s)
- Kathryn Dumschott
- Rheinisch-Westfälische Technische Hochschule Aachen University, 52062 Aachen, NRW, Germany.
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28
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Ishikawa Y, Miyagi A, Ishikawa T, Nagano M, Yamaguchi M, Hihara Y, Kaneko Y, Kawai-Yamada M. One of the NAD kinases, sll1415, is required for the glucose metabolism of Synechocystis sp. PCC 6803. Plant J 2019; 98:654-666. [PMID: 30693583 DOI: 10.1111/tpj.14262] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 01/09/2019] [Accepted: 01/18/2019] [Indexed: 05/04/2023]
Abstract
Pyridine nucleotides (NAD(P)(H)) are electron carriers that are the driving forces in various metabolic pathways. Phosphorylation of NAD(H) to NADP(H) is performed by the enzyme NAD kinase (NADK). Synechocystis sp. PCC 6803 harbors two genes (sll1415 and slr0400) that encode proteins with NADK homology. When genetic mutants for sll1415 and slr0400 (Δ1415 and Δ0400, respectively) were cultured under photoheterotrophic growth conditions only the Δ1415 cells showed a growth defect. In wild-type cells, the sll1415 transcript accumulated after the cells were transferred to photoheterotrophic conditions. Furthermore, NAD(P)(H) measurements demonstrated that a dynamic metabolic conversion was implemented during the adaptation from photoautotrophic to photoheterotrophic conditions. Electron microscopy observation and biochemistry quantification demonstrated the accumulation of glycogen in the Δ1415 cells under photoheterotrophic conditions at 96 h. Quantitative real-time reverse transcription PCR (qRT-PCR) demonstrated the accumulation of mRNAs that encoded glycogen biosynthesis-related enzymes in photoheterotrophic Δ1415 cells. At 96 h, enzyme activity measurement in the photoheterotrophic Δ1415 cells demonstrated that the activities of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were decreased, but the activities of glucose dehydrogenase were increased. Furthermore, metabolomics analysis demonstrated that the Δ1415 cells showed increased glucose-6-phosphate and 6-phosphogluconate content at 96 h. Therefore, sll1415 has a significant function in the oxidative pentose phosphate (OPP) pathway for catabolism of glucose under photoheterotrophic conditions. Additionally, it is presumed that the slr0400 had a different role in glucose catabolism during growth. These results suggest that the two Synechocystis sp. PCC 6803 NADKs (Sll1415 and Slr0400) have distinct functions in photoheterotrophic cyanobacterial metabolism.
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Affiliation(s)
- Yuuma Ishikawa
- Graduate School of Science and Engineering, Saitama University, 225 Shimo-Okubo, Sakura-ku, Saitama-city, Saitama, 338-8570, Japan
| | - Atsuko Miyagi
- Graduate School of Science and Engineering, Saitama University, 225 Shimo-Okubo, Sakura-ku, Saitama-city, Saitama, 338-8570, Japan
| | - Toshiki Ishikawa
- Graduate School of Science and Engineering, Saitama University, 225 Shimo-Okubo, Sakura-ku, Saitama-city, Saitama, 338-8570, Japan
| | - Minoru Nagano
- Graduate School of Science, Ritsumeikan University, Kusatsu, Japan
| | - Masatoshi Yamaguchi
- Graduate School of Science and Engineering, Saitama University, 225 Shimo-Okubo, Sakura-ku, Saitama-city, Saitama, 338-8570, Japan
| | - Yukako Hihara
- Graduate School of Science and Engineering, Saitama University, 225 Shimo-Okubo, Sakura-ku, Saitama-city, Saitama, 338-8570, Japan
| | - Yasuko Kaneko
- Graduate School of Science and Engineering, Saitama University, 225 Shimo-Okubo, Sakura-ku, Saitama-city, Saitama, 338-8570, Japan
| | - Maki Kawai-Yamada
- Graduate School of Science and Engineering, Saitama University, 225 Shimo-Okubo, Sakura-ku, Saitama-city, Saitama, 338-8570, Japan
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29
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Olagaray KE, Brouk MJ, Mamedova LK, Sivinski SE, Liu H, Robert F, Dupuis E, Zachut M, Bradford BJ. Dietary supplementation of Scutellaria baicalensis extract during early lactation decreases milk somatic cells and increases whole lactation milk yield in dairy cattle. PLoS One 2019; 14:e0210744. [PMID: 30673736 PMCID: PMC6343908 DOI: 10.1371/journal.pone.0210744] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Accepted: 12/30/2018] [Indexed: 11/18/2022] Open
Abstract
Systemic inflammation is common in early lactation dairy cows and is associated with decreased milk production. The Scutellaria baicalensis plant contains flavonoids with anti-inflammatory and anti-oxidative properties, which may counteract the inflammatory state in early lactation dairy cows. The objective of this experiment was to determine whether Scutellaria baicalensis extract (SBE), a source of bioactive flavonoids, would alter the adaptation to lactation. Multiparous Holstein cows (n = 122) were used in a randomized block design to determine the effect of short-term and long-term postpartum administration of SBE on 305-d milk yield, 120-d milk component yield, and early lactation milk markers of inflammation and metabolic function. Treatments were 1) control, 2) short term (5-d) administration of the SBE (SBE5), and 3) long term (60-d) administration of the SBE (SBE60). Treatments were included in a treatment pellet that was identical to a control pellet in ingredient source and composition except for the extract (10 g/d SBE providing 3.3 g/d of the flavonoid baicalin), both provided via an automated milking system beginning on d 1 of lactation. Milk samples were collected on d 1, 3, and once during d 5–12 of lactation, followed by weekly sampling until 120 days in milk (DIM). Milk samples collected in the first 2 wk were used for biomarker analysis (haptoglobin, β-hydroxybutyrate [BHB], and glucose-6-phosphate [G6P]), and all samples were used for composition analysis. Cows were body condition scored every 2 wk prepartum and postpartum. Milk production, programmed pellet allocation, and actual provision of both pelleted feeds were recorded daily. Treatment effects were evaluated by contrasts between control and SBE5 and control and SBE60 for both the treatment (TP; wk 1–9) and carryover periods (CP; wk 10–37). Total pellet offered was greater for SBE60 in both the TP (P < 0.01) and CP (P = 0.02) but was not different for SBE5 during either period (P ≥ 0.13). No treatment effects were observed for body condition score (BCS), milk haptoglobin, BHB, or G6P. SBE5 did not alter milk yield or milk components. SBE60 increased whole-lactation milk yield by 1,419 kg (13%; P = 0.03). SBE60 increased milk lactose and fat yields (P ≤ 0.04) and tended to increase milk protein yield (P = 0.09) during TP, and each increased during CP (P ≤ 0.04). Somatic cell count decreased by 10% in SBE60 during TP (P = 0.02) but not CP (P = 0.13). Mastitis incidence tended to differ by treatment, being lesser for both SBE5 and SBE60 vs. control (14 and 15% vs. 33%). SBE supplementation did not impact time to pregnancy or hazard of leaving the herd. In conclusion, despite no detected treatment effects on BCS or milk biomarkers of inflammation and metabolic status, supplementation of postpartum dairy cows with Scutellaria baicalensis extract for 60 d was effective at increasing whole lactation milk yield.
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Affiliation(s)
- K. E. Olagaray
- Department of Animal Sciences and Industry, Kansas State University, Manhattan, Kansas, United States of America
| | - M. J. Brouk
- Department of Animal Sciences and Industry, Kansas State University, Manhattan, Kansas, United States of America
| | - L. K. Mamedova
- Department of Animal Sciences and Industry, Kansas State University, Manhattan, Kansas, United States of America
| | - S. E. Sivinski
- Department of Animal Sciences and Industry, Kansas State University, Manhattan, Kansas, United States of America
| | - H. Liu
- Department of Animal Sciences and Industry, Kansas State University, Manhattan, Kansas, United States of America
| | | | | | - M. Zachut
- Agriculture Research Organization, Volcani Center, Rishon Lezion, Israel
| | - B. J. Bradford
- Department of Animal Sciences and Industry, Kansas State University, Manhattan, Kansas, United States of America
- * E-mail:
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30
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Petchampai N, Murillo-Solano C, Isoe J, Pizarro JC, Scaraffia PY. Distinctive regulatory properties of pyruvate kinase 1 from Aedes aegypti mosquitoes. Insect Biochem Mol Biol 2019; 104:82-90. [PMID: 30578824 PMCID: PMC6814295 DOI: 10.1016/j.ibmb.2018.12.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 12/17/2018] [Accepted: 12/17/2018] [Indexed: 05/17/2023]
Abstract
Female Aedes aegypti mosquitoes are vectors of arboviruses that cause diseases of public health significance. The discovery of new metabolic targets is crucial for improving mosquito control strategies. We recently demonstrated that glucose oxidation supports ammonia detoxification in A. aegypti. Pyruvate kinase (PK, EC 2.7.1.40) catalyzes the last step of the glycolytic pathway. In most organisms, one or more allosteric effectors control PK activity. However, the kinetic properties and structure of PK in mosquitoes have not been previously reported. In this study, two alternatively spliced mRNA variants (AaPK1 and AaPK2) that code for PKs were identified in the A. aegypti genome. The AaPK1 mRNA variant, which encodes a 529 amino acid protein with an estimated molecular weight of ∼57 kDa, was cloned. The protein was expressed in Escherichia coli and purified. The AaPK1 kinetic properties were identified. The recombinant protein was also crystallized and its 3D structure determined. We found that alanine, glutamine, proline, serine and fructose-1-phosphate displayed a classic allosteric activation on AaPK1. Ribulose-5-phosphate acted as an allosteric inhibitor of AaPK1 but its inhibitory effect was reversed by alanine, glutamine, proline and serine. Additionally, the allosteric activation of AaPK1 by amino acids was weakened by fructose-1,6-bisphosphate, whereas the allosteric activation of AaPK1 by alanine and serine was diminished by glucose-6-phosphate. The AaPK1 structure shows the presence of fructose-1,6-bisphosphate in the allosteric site. Together, our results reveal that specific amino acids and phosphorylated sugars tightly regulate conformational dynamics and catalytic changes of AaPK1. The distinctive AaPK1 allosteric properties support a complex role for this enzyme within mosquito metabolism.
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Affiliation(s)
- Natthida Petchampai
- Department of Tropical Medicine, Vector-Borne Infectious Disease Research Center, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA, 70112, USA
| | - Claribel Murillo-Solano
- Department of Tropical Medicine, Vector-Borne Infectious Disease Research Center, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA, 70112, USA
| | - Jun Isoe
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, AZ, 85721, USA
| | - Juan C Pizarro
- Department of Tropical Medicine, Vector-Borne Infectious Disease Research Center, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA, 70112, USA.
| | - Patricia Y Scaraffia
- Department of Tropical Medicine, Vector-Borne Infectious Disease Research Center, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA, 70112, USA.
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31
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Bak AM, Vendelbo MH, Christensen B, Viggers R, Bibby BM, Rungby J, Jørgensen JOL, Møller N, Jessen N. Prolonged fasting-induced metabolic signatures in human skeletal muscle of lean and obese men. PLoS One 2018; 13:e0200817. [PMID: 30183740 PMCID: PMC6124727 DOI: 10.1371/journal.pone.0200817] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 07/03/2018] [Indexed: 11/19/2022] Open
Abstract
Insulin resistance is a well-known physiological adaptation to prolonged fasting in healthy skeletal muscle. Obesity is associated with insulin resistance and metabolic inflexibility in skeletal muscle, and a pronounced increase in the risk of metabolic complications. Under the hypothesis that the metabolic traits of insulin resistance associated with prolonged fasting are different from insulin resistance associated with obesity, we examined nine obese and nine lean participants during 12 and 72h of fasting, respectively. Insulin resistance in obese participants was associated with impaired insulin signaling, and reduced levels of glucose-6-phosphate and TCA-cycle intermediates. 72h of fasting in lean participants reduced insulin-stimulated glucose uptake to levels similar to obese participants fasted for 12h. This was associated with increased lipid oxidation, but not accumulation of diacylglycerol or acylcarnitines and impairment of insulin signaling. Prolonged fasting was associated with pronounced increases in β-hydroxybutyrate and β- hydroxybutyrylcarnitine levels in skeletal muscle suggesting augmented ketone body metabolism. Fasting induced insulin resistance may be a consequence of substrate competition. The underlying mechanism behind insulin resistance in obesity is thus not comparable to the physiological adaptations in skeletal muscle induced by prolonged fasting in lean participants.
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Affiliation(s)
- Ann Mosegaard Bak
- Medical Research Laboratory, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Department of Endocrinology and Internal Medicine (MEA), Aarhus University Hospital, Aarhus, Denmark
- * E-mail:
| | - Mikkel Holm Vendelbo
- Medical Research Laboratory, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Department of Nuclear Medicine and PET Center, Aarhus University Hospital, Aarhus, Denmark
| | - Britt Christensen
- Department of Endocrinology and Internal Medicine (MEA), Aarhus University Hospital, Aarhus, Denmark
- Research Laboratory for Biochemical Pathology, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Rikke Viggers
- Medical Research Laboratory, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Research Laboratory for Biochemical Pathology, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Bo Martin Bibby
- Department of Public Health, Aarhus University, Aarhus, Denmark
| | - Jørgen Rungby
- Department of Biomedicine, Aarhus University, Denmark
| | - Jens Otto Lunde Jørgensen
- Medical Research Laboratory, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Department of Endocrinology and Internal Medicine (MEA), Aarhus University Hospital, Aarhus, Denmark
| | - Niels Møller
- Medical Research Laboratory, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Department of Endocrinology and Internal Medicine (MEA), Aarhus University Hospital, Aarhus, Denmark
| | - Niels Jessen
- Department of Endocrinology and Internal Medicine (MEA), Aarhus University Hospital, Aarhus, Denmark
- Department of Biomedicine, Aarhus University, Denmark
- Department of Clinical Pharmacology, Aarhus University Hospital, Denmark
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32
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Bahaji A, Almagro G, Ezquer I, Gámez-Arcas S, Sánchez-López ÁM, Muñoz FJ, Barrio RJ, Sampedro MC, De Diego N, Spíchal L, Doležal K, Tarkowská D, Caporali E, Mendes MA, Baroja-Fernández E, Pozueta-Romero J. Plastidial Phosphoglucose Isomerase Is an Important Determinant of Seed Yield through Its Involvement in Gibberellin-Mediated Reproductive Development and Storage Reserve Biosynthesis in Arabidopsis. Plant Cell 2018; 30:2082-2098. [PMID: 30099384 PMCID: PMC6181017 DOI: 10.1105/tpc.18.00312] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 07/18/2018] [Accepted: 08/06/2018] [Indexed: 05/04/2023]
Abstract
The plastid-localized phosphoglucose isomerase isoform PGI1 is an important determinant of growth in Arabidopsis thaliana, likely due to its involvement in the biosynthesis of plastidial isoprenoid-derived hormones. Here, we investigated whether PGI1 also influences seed yields. PGI1 is strongly expressed in maturing seed embryos and vascular tissues. PGI1-null pgi1-2 plants had ∼60% lower seed yields than wild-type plants, with reduced numbers of inflorescences and thus fewer siliques and seeds per plant. These traits were associated with low bioactive gibberellin (GA) contents. Accordingly, wild-type phenotypes were restored by exogenous GA application. pgi1-2 seeds were lighter and accumulated ∼50% less fatty acids (FAs) and ∼35% less protein than wild-type seeds. Seeds of cytokinin-deficient plants overexpressing CYTOKININ OXIDASE/DEHYDROGENASE1 (35S:AtCKX1) and GA-deficient ga20ox1 ga20ox2 mutants did not accumulate low levels of FAs, and exogenous application of the cytokinin 6-benzylaminopurine and GAs did not rescue the reduced weight and FA content of pgi1-2 seeds. Seeds from reciprocal crosses between pgi1-2 and wild-type plants accumulated wild-type levels of FAs and proteins. Therefore, PGI1 is an important determinant of Arabidopsis seed yield due to its involvement in two processes: GA-mediated reproductive development and the metabolic conversion of plastidial glucose-6-phosphate to storage reserves in the embryo.
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Affiliation(s)
- Abdellatif Bahaji
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), 31192 Mutiloabeti, Nafarroa, Spain
| | - Goizeder Almagro
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), 31192 Mutiloabeti, Nafarroa, Spain
| | - Ignacio Ezquer
- Dipartimento di BioScienze, Università degli Studi di Milano, 20133 Milan, Italy
| | - Samuel Gámez-Arcas
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), 31192 Mutiloabeti, Nafarroa, Spain
| | | | - Francisco José Muñoz
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), 31192 Mutiloabeti, Nafarroa, Spain
| | - Ramón José Barrio
- Department of Analytical Chemistry, Faculty of Pharmacy, University of the Basque Country, UPV/EHU, E-01006 Vitoria-Gasteiz, Spain
| | - M Carmen Sampedro
- Central Service of Analysis of Alava, SGIker, University of the Basque Country, UPV/EHU, E-01006 Vitoria-Gasteiz, Spain
| | - Nuria De Diego
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, CZ-78371 Olomouc, Czech Republic
| | - Lukáš Spíchal
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, CZ-78371 Olomouc, Czech Republic
| | - Karel Doležal
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, CZ-78371 Olomouc, Czech Republic
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany AS CR and Faculty of Science, Palacký University, CZ-78371 Olomouc, Czech Republic
| | - Danuše Tarkowská
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany AS CR and Faculty of Science, Palacký University, CZ-78371 Olomouc, Czech Republic
| | - Elisabetta Caporali
- Dipartimento di BioScienze, Università degli Studi di Milano, 20133 Milan, Italy
| | - Marta Adelina Mendes
- Dipartimento di BioScienze, Università degli Studi di Milano, 20133 Milan, Italy
| | - Edurne Baroja-Fernández
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), 31192 Mutiloabeti, Nafarroa, Spain
| | - Javier Pozueta-Romero
- Instituto de Agrobiotecnología (CSIC/UPNA/Gobierno de Navarra), 31192 Mutiloabeti, Nafarroa, Spain
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Zhang C, Allen KN, Dunaway-Mariano D. Mechanism of Substrate Recognition and Catalysis of the Haloalkanoic Acid Dehalogenase Family Member α-Phosphoglucomutase. Biochemistry 2018; 57:4504-4517. [PMID: 29952545 PMCID: PMC10725300 DOI: 10.1021/acs.biochem.8b00396] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
α-Phosphoglucomutase (αPGM), in its phosphorylated state, catalyzes the interconversion of α-d-glucose 1-phosphate and α-d-glucose 6-phosphate. The αPGM of Lactococcus lactis is a type C2B member of the haloalkanoic acid dehalogenase (HAD) enzyme family and is comprised of a Rossmann-fold catalytic domain and inserted α/β-fold cap domain. The active site is formed at the domain-domain interface. Herein, we report the results from a kinetic-based study of L. lactis αPGM catalysis, which demonstrate enzyme activation by autocatalyzed phosphorylation of Asp8 with αG1P, the intermediacy of αG1,6bisP in the phospho Ll-αPGM-catalyzed conversion of αG1P to G6P, and the reorientation of the αG1,6bisP intermediate via dissociation to solvent and rebinding. In order to provide insight into the structural determinants of L. lactis αPGM substrate recognition and catalysis, metal cofactor and substrate specificities were determined as were the contributions made by active-site residues toward catalytic efficiency. Lastly, the structure and catalytic mechanism of L. lactis αPGM are compared with those of HAD family phosphomutases L. lactis β-phosphoglucomutase and eukayotic α-phosphomannomutase to provide insight into the evolution of phosphohexomutases from HAD family phosphatases.
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Affiliation(s)
- Chunchun Zhang
- Testing & Analytical Center, Sichuan University, Chengdu, Sichuan 610064, P. R. China
| | - Karen N. Allen
- Department of Chemistry, Boston University, Boston MA 02215-2521
| | - Debra Dunaway-Mariano
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131
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Troncoso-Ponce MA, Rivoal J, Dorion S, Sánchez R, Venegas-Calerón M, Moreno-Pérez AJ, Baud S, Garcés R, Martínez-Force E. Molecular and biochemical characterization of the sunflower (Helianthus annuus L.) cytosolic and plastidial enolases in relation to seed development. Plant Sci 2018; 272:117-130. [PMID: 29807582 DOI: 10.1016/j.plantsci.2018.04.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 04/08/2018] [Accepted: 04/10/2018] [Indexed: 05/19/2023]
Abstract
In the present study, we describe the molecular and biochemical characterization of sunflower (Helianthus annuus L.) enolase (ENO, EC 4.2.1.11) proteins, which catalyze the formation of phosphoenolpyruvate, the penultimate intermediate in the glycolytic pathway. We cloned and characterized three cDNAs encoding different ENO isoforms from developing sunflower seeds. Studies using fluorescently tagged ENOs confirmed the predicted subcellular localization of ENO isoforms: HaENO1 in the plastid while HaENO2 and HaENO3 were found in the cytosol. The cDNAs were used to express the corresponding 6(His)-tagged proteins in Escherichia coli. The proteins were purified to electrophoretic homogeneity, using immobilized metal ion affinity chromatography, and biochemically characterized. Recombinant HaENO1 and HaENO2, but not HaENO3 were shown to have enolase activity, in agreement with data obtained with the Arabidopsis homolog proteins. Site directed mutagenesis of several critical amino acids was used to attempt to recover enolase activity in recombinant HaENO3, resulting in very small increases that were not additive. A kinetic characterization of the two active isoforms showed that pH had similar effect on their velocity, that they had similar affinity for 2-phosphoglycerate, but that the kcat/Km of the plastidial enzyme was higher than that of the cytosolic isoform. Even though HaENO2 was always the most highly expressed transcript, the levels of expression of the three ENO genes were remarkably distinct in all the vegetative and reproductive tissues studied. This indicates that in seeds the conversion of 2-phosphoglycerate to phosphoenolpyruvate takes place through the cytosolic and the plastidial pathways therefore both routes could contribute to the supply of carbon for lipid synthesis. The identity of the main source of carbon during the period of stored products synthesis is discussed.
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Affiliation(s)
- M A Troncoso-Ponce
- Instituto de la Grasa (CSIC), Edificio 46, Campus Universitario Pablo de Olavide, Carretera de Utrera Km 1, 41013, Sevilla, Spain; Sorbonne University, Université de technologie de Compiègne, CNRS, Institute for Enzyme and Cell Engineering, Centre de recherche Royallieu, CS 60 319, 60 203 Compiègne cedex, France.
| | - J Rivoal
- Institut de Recherche en Biologie Végétale, Université de Montréal, 4101 Rue Sherbrooke est, Montréal, QC, Canada
| | - S Dorion
- Institut de Recherche en Biologie Végétale, Université de Montréal, 4101 Rue Sherbrooke est, Montréal, QC, Canada
| | - R Sánchez
- Instituto de la Grasa (CSIC), Edificio 46, Campus Universitario Pablo de Olavide, Carretera de Utrera Km 1, 41013, Sevilla, Spain
| | - M Venegas-Calerón
- Instituto de la Grasa (CSIC), Edificio 46, Campus Universitario Pablo de Olavide, Carretera de Utrera Km 1, 41013, Sevilla, Spain
| | - A J Moreno-Pérez
- Instituto de la Grasa (CSIC), Edificio 46, Campus Universitario Pablo de Olavide, Carretera de Utrera Km 1, 41013, Sevilla, Spain
| | - S Baud
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000 Versailles, France
| | - R Garcés
- Instituto de la Grasa (CSIC), Edificio 46, Campus Universitario Pablo de Olavide, Carretera de Utrera Km 1, 41013, Sevilla, Spain
| | - E Martínez-Force
- Instituto de la Grasa (CSIC), Edificio 46, Campus Universitario Pablo de Olavide, Carretera de Utrera Km 1, 41013, Sevilla, Spain
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Beneyton T, Krafft D, Bednarz C, Kleineberg C, Woelfer C, Ivanov I, Vidaković-Koch T, Sundmacher K, Baret JC. Out-of-equilibrium microcompartments for the bottom-up integration of metabolic functions. Nat Commun 2018; 9:2391. [PMID: 29921909 PMCID: PMC6008305 DOI: 10.1038/s41467-018-04825-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 05/21/2018] [Indexed: 12/19/2022] Open
Abstract
Self-sustained metabolic pathways in microcompartments are the corner-stone for living systems. From a technological viewpoint, such pathways are a mandatory prerequisite for the reliable design of artificial cells functioning out-of-equilibrium. Here we develop a microfluidic platform for the miniaturization and analysis of metabolic pathways in man-made microcompartments formed of water-in-oil droplets. In a modular approach, we integrate in the microcompartments a nicotinamide adenine dinucleotide (NAD)-dependent enzymatic reaction and a NAD-regeneration module as a minimal metabolism. We show that the microcompartments sustain a metabolically active state until the substrate is fully consumed. Reversibly, the external addition of the substrate reboots the metabolic activity of the microcompartments back to an active state. We therefore control the metabolic state of thousands of independent monodisperse microcompartments, a step of relevance for the construction of large populations of metabolically active artificial cells.
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Affiliation(s)
- Thomas Beneyton
- CNRS, Univ. Bordeaux, CRPP, UMR 5031, 115 Avenue Schweitzer, 33600, Pessac, France
| | - Dorothee Krafft
- Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106, Magdeburg, Germany
| | - Claudia Bednarz
- Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106, Magdeburg, Germany
| | - Christin Kleineberg
- Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106, Magdeburg, Germany
| | - Christian Woelfer
- Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106, Magdeburg, Germany
| | - Ivan Ivanov
- Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106, Magdeburg, Germany
| | - Tanja Vidaković-Koch
- Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106, Magdeburg, Germany
| | - Kai Sundmacher
- Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106, Magdeburg, Germany
- Otto-von-Guericke University, Process Systems Engineering, Universitätsplatz 2, 39106, Magdeburg, Germany
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Farah BL, Landau DJ, Wu Y, Sinha RA, Loh A, Bay BH, Koeberl DD, Yen PM. Renal endoplasmic reticulum stress is coupled to impaired autophagy in a mouse model of GSD Ia. Mol Genet Metab 2017; 122:95-98. [PMID: 28888852 PMCID: PMC5722666 DOI: 10.1016/j.ymgme.2017.08.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 08/23/2017] [Accepted: 08/24/2017] [Indexed: 10/18/2022]
Abstract
GSD Ia (von Gierke Disease, Glycogen Storage Disease Type Ia) is a devastating genetic disorder with long-term sequelae, such as non-alcoholic fatty liver disease and renal failure. Down-regulated autophagy is involved in the development of hepatic metabolic dysfunction in GSD Ia; however, the role of autophagy in the renal pathology is unknown. Here we show that autophagy is impaired and endoplasmic reticulum (ER) stress is increased in the kidneys of a mouse model of GSD Ia. Induction of autophagy by rapamycin also reduces this ER stress. Taken together, these results show an additional role for autophagy down-regulation in the pathogenesis of GSD Ia, and provide further justification for the use of autophagy modulators in GSD Ia.
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Affiliation(s)
- Benjamin L Farah
- Cardiovascular and Metabolic Disorders Program, Duke-NUS Medical School, Singapore, Singapore
| | - Dustin J Landau
- Division of Medical Genetics, Department of Pediatrics, Duke University Medical School, Durham, NC, USA; Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
| | - Yajun Wu
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Rohit A Sinha
- Cardiovascular and Metabolic Disorders Program, Duke-NUS Medical School, Singapore, Singapore
| | - Alwin Loh
- Division of Pathology, Singapore General Hospital, Singapore
| | - Boon-Huat Bay
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Dwight D Koeberl
- Division of Medical Genetics, Department of Pediatrics, Duke University Medical School, Durham, NC, USA; Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
| | - Paul M Yen
- Cardiovascular and Metabolic Disorders Program, Duke-NUS Medical School, Singapore, Singapore; Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, NC, USA.
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Al-Oanzi ZH, Fountana S, Moonira T, Tudhope SJ, Petrie JL, Alshawi A, Patman G, Arden C, Reeves HL, Agius L. Opposite effects of a glucokinase activator and metformin on glucose-regulated gene expression in hepatocytes. Diabetes Obes Metab 2017; 19:1078-1087. [PMID: 28206714 DOI: 10.1111/dom.12910] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 02/10/2017] [Accepted: 02/11/2017] [Indexed: 01/19/2023]
Abstract
AIM Small molecule activators of glucokinase (GKAs) have been explored extensively as potential anti-hyperglycaemic drugs for type 2 diabetes (T2D). Several GKAs were remarkably effective in lowering blood glucose during early therapy but then lost their glycaemic efficacy chronically during clinical trials. MATERIALS AND METHODS We used rat hepatocytes to test the hypothesis that GKAs raise hepatocyte glucose 6-phosphate (G6P, the glucokinase product) and down-stream metabolites with consequent repression of the liver glucokinase gene ( Gck). We compared a GKA with metformin, the most widely prescribed drug for T2D. RESULTS Treatment of hepatocytes with 25 mM glucose raised cell G6P, concomitantly with Gck repression and induction of G6pc (glucose 6-phosphatase) and Pklr (pyruvate kinase). A GKA mimicked high glucose by raising G6P and fructose-2,6-bisphosphate, a regulatory metabolite, causing a left-shift in glucose responsiveness on gene regulation. Fructose, like the GKA, repressed Gck but modestly induced G6pc. 2-Deoxyglucose, which is phosphorylated by glucokinase but not further metabolized caused Gck repression but not G6pc induction, implicating the glucokinase product in Gck repression. Metformin counteracted the effect of high glucose on the elevated G6P and fructose 2,6-bisphosphate and on Gck repression, recruitment of Mlx-ChREBP to the G6pc and Pklr promoters and induction of these genes. CONCLUSIONS Elevation in hepatocyte G6P and downstream metabolites, with consequent liver Gck repression, is a potential contributing mechanism to the loss of GKA efficacy during chronic therapy. Cell metformin loads within the therapeutic range attenuate the effect of high glucose on G6P and on glucose-regulated gene expression.
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Affiliation(s)
- Ziad H Al-Oanzi
- Institute of Cellular Medicine and Ageing and Health, Newcastle University, Newcastle upon Tyne, UK
- Medical Laboratory Science, Aljouf University, Sakaka, Saudi Arabia
| | - Sophia Fountana
- Institute of Cellular Medicine and Ageing and Health, Newcastle University, Newcastle upon Tyne, UK
| | - Tabassum Moonira
- Institute of Cellular Medicine and Ageing and Health, Newcastle University, Newcastle upon Tyne, UK
| | - Susan J Tudhope
- Institute of Cellular Medicine and Ageing and Health, Newcastle University, Newcastle upon Tyne, UK
| | - John L Petrie
- Institute of Cellular Medicine and Ageing and Health, Newcastle University, Newcastle upon Tyne, UK
| | - Ahmed Alshawi
- Institute of Cellular Medicine and Ageing and Health, Newcastle University, Newcastle upon Tyne, UK
| | - Gillian Patman
- Northern Institute for Cancer Research, Newcastle University, Newcastle-upon-Tyne, UK
| | - Catherine Arden
- Institute of Cellular Medicine and Ageing and Health, Newcastle University, Newcastle upon Tyne, UK
| | - Helen L Reeves
- Northern Institute for Cancer Research, Newcastle University, Newcastle-upon-Tyne, UK
| | - Loranne Agius
- Institute of Cellular Medicine and Ageing and Health, Newcastle University, Newcastle upon Tyne, UK
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Zhang C, Luo H, Huang L, Lin S. Molecular mechanism of glucose-6-phosphate utilization in the dinoflagellate Karenia mikimotoi. Harmful Algae 2017; 67:74-84. [PMID: 28755722 DOI: 10.1016/j.hal.2017.06.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Revised: 06/19/2017] [Accepted: 06/19/2017] [Indexed: 06/07/2023]
Abstract
Phosphorus (P) is an essential nutrient for marine phytoplankton as for other living organisms, and the preferred form, dissolved inorganic phosphate (DIP), is often quickly depleted in the sunlit layer of the ocean. Phytoplankton have developed mechanisms to utilize organic forms of P (DOP). Hydrolysis of DOP to release DIP by alkaline phosphatase is believed to be the most common mechanism of DOP utilization. Little effort has been made, however, to understand other potential molecular mechanisms of utilizing different types of DOP. This study investigated the bioavailability of glucose-6-phosphate (G6P) and its underlying molecular mechanism in the dinoflagellate Karenia mikimotoi. Suppression Subtraction Hybridization (SSH) was used to identify genes up- and down-regulated during G6P utilization compared to DIP condition. The results showed that G6P supported the growth and yield of K. mikimotoi as efficiently as DIP. Neither DIP release nor AP activity was detected in the cultures grown in G6P medium, however, suggesting direct uptake of G6P. SSH analysis and RT-qPCR results showed evidence of metabolic modifications, particularly that mitochondrial ATP synthase f1gamma subunit and thioredoxin reductase were up-regulated while diphosphatase and pyrophosphatase were down-regulated in the G6P cultures. All the results indicate that K. mikimotoi has developed a mechanism other than alkaline phosphatase to utilize G6P.
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Affiliation(s)
- Chao Zhang
- South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, Guangdong, China; Institute of Genetic Engineering, Southern Medical University, Guangzhou, China, Guangdong Province Key Laboratory of Biochip, School of Basic Medical Science, Southern Medical University, Guangzhou, China
| | - Hao Luo
- Key State Laboratory of Marine Environmental Science and Marine Biodiversity and Global Change Research Center, Xiamen University, Xiamen, Fujian, China
| | - Liangmin Huang
- South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, Guangdong, China
| | - Senjie Lin
- Key State Laboratory of Marine Environmental Science and Marine Biodiversity and Global Change Research Center, Xiamen University, Xiamen, Fujian, China; Department of Marine Sciences, University of Connecticut, Groton, CT 06340, USA.
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Sylow L, Møller LLV, Kleinert M, D'Hulst G, De Groote E, Schjerling P, Steinberg GR, Jensen TE, Richter EA. Rac1 and AMPK Account for the Majority of Muscle Glucose Uptake Stimulated by Ex Vivo Contraction but Not In Vivo Exercise. Diabetes 2017; 66:1548-1559. [PMID: 28389470 DOI: 10.2337/db16-1138] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 03/15/2017] [Indexed: 11/13/2022]
Abstract
Exercise bypasses insulin resistance to increase glucose uptake in skeletal muscle and therefore represents an important alternative to stimulate glucose uptake in insulin-resistant muscle. Both Rac1 and AMPK have been shown to partly regulate contraction-stimulated muscle glucose uptake, but whether those two signaling pathways jointly account for the entire signal to glucose transport is unknown. We therefore studied the ability of contraction and exercise to stimulate glucose transport in isolated muscles with AMPK loss of function combined with either pharmacological inhibition or genetic deletion of Rac1.Muscle-specific knockout (mKO) of Rac1, a kinase-dead α2 AMPK (α2KD), and double knockout (KO) of β1 and β2 AMPK subunits (β1β2 KO) each partially decreased contraction-stimulated glucose transport in mouse soleus and extensor digitorum longus (EDL) muscle. Interestingly, when pharmacological Rac1 inhibition was combined with either AMPK β1β2 KO or α2KD, contraction-stimulated glucose transport was almost completely inhibited. Importantly, α2KD+Rac1 mKO double-transgenic mice also displayed severely impaired contraction-stimulated glucose transport, whereas exercise-stimulated glucose uptake in vivo was only partially reduced by Rac1 mKO with no additive effect of α2KD. It is concluded that Rac1 and AMPK together account for almost the entire ex vivo contraction response in muscle glucose transport, whereas only Rac1, but not α2 AMPK, regulates muscle glucose uptake during submaximal exercise in vivo.
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Affiliation(s)
- Lykke Sylow
- Molecular Physiology Group, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Lisbeth L V Møller
- Molecular Physiology Group, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Maximilian Kleinert
- Molecular Physiology Group, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Gommaar D'Hulst
- Department of Kinesiology, Exercise Physiology Research Group, Faculty of Kinesiology and Rehabilitation Sciences, KU Leuven, Leuven, Belgium
| | | | - Peter Schjerling
- Institute of Sports Medicine, Department of Orthopedic Surgery, Bispebjerg Hospital, Copenhagen, Denmark
- Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Gregory R Steinberg
- Division of Endocrinology and Metabolism, Department of Medicine and Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
| | - Thomas E Jensen
- Molecular Physiology Group, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Erik A Richter
- Molecular Physiology Group, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
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Cheung CYY, Tang CS, Xu A, Lee CH, Au KW, Xu L, Fong CHY, Kwok KHM, Chow WS, Woo YC, Yuen MMA, Cherny SS, Hai J, Cheung BMY, Tan KCB, Lam TH, Tse HF, Sham PC, Lam KSL. An Exome-Chip Association Analysis in Chinese Subjects Reveals a Functional Missense Variant of GCKR That Regulates FGF21 Levels. Diabetes 2017; 66:1723-1728. [PMID: 28385800 DOI: 10.2337/db16-1384] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 03/10/2017] [Indexed: 11/13/2022]
Abstract
Fibroblast growth factor 21 (FGF21) is increasingly recognized as an important metabolic regulator of glucose homeostasis. Here, we conducted an exome-chip association analysis by genotyping 5,169 Chinese individuals from a community-based cohort and two clinic-based cohorts. A custom Asian exome-chip was used to detect genetic determinants influencing circulating FGF21 levels. Single-variant association analysis interrogating 70,444 single nucleotide polymorphisms identified a novel locus, GCKR, significantly associated with circulating FGF21 levels at genome-wide significance. In the combined analysis, the common missense variant of GCKR, rs1260326 (p.Pro446Leu), showed an association with FGF21 levels after adjustment for age and sex (P = 1.61 × 10-12; β [SE] = 0.14 [0.02]), which remained significant on further adjustment for BMI (P = 3.01 × 10-14; β [SE] = 0.15 [0.02]). GCKR Leu446 may influence FGF21 expression via its ability to increase glucokinase (GCK) activity. This can lead to enhanced FGF21 expression via elevated fatty acid synthesis, consequent to the inhibition of carnitine/palmitoyl-transferase by malonyl-CoA, and via increased glucose-6-phosphate-mediated activation of the carbohydrate response element binding protein, known to regulate FGF21 gene expression. Our findings shed new light on the genetic regulation of FGF21 levels. Further investigations to dissect the relationship between GCKR and FGF21, with respect to the risk of metabolic diseases, are warranted.
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Affiliation(s)
- Chloe Y Y Cheung
- Department of Medicine, The University of Hong Kong, Hong Kong, China
| | - Clara S Tang
- Department of Surgery, The University of Hong Kong, Hong Kong, China
| | - Aimin Xu
- Department of Medicine, The University of Hong Kong, Hong Kong, China
- The State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong, China
- Research Centre of Heart, Brain, Hormone & Healthy Aging, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
- Department of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong, China
| | - Chi-Ho Lee
- Department of Medicine, The University of Hong Kong, Hong Kong, China
| | - Ka-Wing Au
- Department of Medicine, The University of Hong Kong, Hong Kong, China
| | - Lin Xu
- School of Public Health, The University of Hong Kong, Hong Kong, China
| | - Carol H Y Fong
- Department of Medicine, The University of Hong Kong, Hong Kong, China
| | - Kelvin H M Kwok
- Department of Medicine, The University of Hong Kong, Hong Kong, China
| | - Wing-Sun Chow
- Department of Medicine, The University of Hong Kong, Hong Kong, China
| | - Yu-Cho Woo
- Department of Medicine, The University of Hong Kong, Hong Kong, China
| | - Michele M A Yuen
- Department of Medicine, The University of Hong Kong, Hong Kong, China
| | - Stacey S Cherny
- Department of Psychiatry, The University of Hong Kong, Hong Kong, China
| | - JoJo Hai
- Department of Medicine, The University of Hong Kong, Hong Kong, China
| | | | - Kathryn C B Tan
- Department of Medicine, The University of Hong Kong, Hong Kong, China
| | - Tai-Hing Lam
- School of Public Health, The University of Hong Kong, Hong Kong, China
| | - Hung-Fat Tse
- Department of Medicine, The University of Hong Kong, Hong Kong, China
- Hong Kong-Guangdong Joint Laboratory on Stem Cell and Regenerative Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Pak-Chung Sham
- Department of Psychiatry, The University of Hong Kong, Hong Kong, China
- Centre for Genomic Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
- The State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, China
| | - Karen S L Lam
- Department of Medicine, The University of Hong Kong, Hong Kong, China
- The State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong, China
- Research Centre of Heart, Brain, Hormone & Healthy Aging, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
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Mercaldi GF, Dawson A, Hunter WN, Cordeiro AT. The structure of a Trypanosoma cruzi glucose-6-phosphate dehydrogenase reveals differences from the mammalian enzyme. FEBS Lett 2016; 590:2776-86. [PMID: 27391210 DOI: 10.1002/1873-3468.12276] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 06/12/2016] [Accepted: 06/24/2016] [Indexed: 11/08/2022]
Abstract
The enzyme glucose-6-phosphate dehydrogenase from Trypanosoma cruzi (TcG6PDH) catalyses the first step of the pentose phosphate pathway (PPP) and is considered a promising target for the discovery of a new drug against Chagas diseases. In the present work, we describe the crystal structure of TcG6PDH obtained in a ternary complex with the substrate β-d-glucose-6-phosphate (G6P) and the reduced 'catalytic' cofactor NADPH, which reveals the molecular basis of substrate and cofactor recognition. A comparison with the homologous human protein sheds light on differences in the cofactor-binding site that might be explored towards the design of new NADP(+) competitive inhibitors targeting the parasite enzyme.
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Affiliation(s)
- Gustavo F Mercaldi
- Brazilian Biosciences National Laboratory, Center of Research in Energy and Materials, Campinas, Brazil
- Institute of Biology, University of Campinas, Brazil
| | - Alice Dawson
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, UK
| | - Willian N Hunter
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, UK
| | - Artur T Cordeiro
- Brazilian Biosciences National Laboratory, Center of Research in Energy and Materials, Campinas, Brazil
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Abstract
It is just over 60 years since a cycle for the regeneration of the CO2-acceptor used in photosynthesis was proposed. In this opinion paper, we revisit the origins of the Calvin-Benson cycle that occurred at the time that the hexose monophosphate shunt, now called the pentose phosphate pathway, was being worked out. Eventually the pentose phosphate pathway was separated into two branches, an oxidative branch and a non-oxidative branch. It is generally thought that the Calvin-Benson cycle is the reverse of the non-oxidative branch of the pentose phosphate pathway but we describe crucial differences and also propose that some carbon routinely passes through the oxidative branch of the pentose phosphate pathway. This creates a futile cycle but may help to stabilize photosynthesis. If it occurs it could explain a number of enigmas including the lack of complete labelling of the Calvin-Benson cycle intermediates when carbon isotopes are fed to photosynthesizing leaves.
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Affiliation(s)
- Thomas D Sharkey
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
| | - Sean E Weise
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
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Gudiksen A, Schwartz CL, Bertholdt L, Joensen E, Knudsen JG, Pilegaard H. Lack of Skeletal Muscle IL-6 Affects Pyruvate Dehydrogenase Activity at Rest and during Prolonged Exercise. PLoS One 2016; 11:e0156460. [PMID: 27327080 PMCID: PMC4915712 DOI: 10.1371/journal.pone.0156460] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 05/13/2016] [Indexed: 12/12/2022] Open
Abstract
Pyruvate dehydrogenase (PDH) plays a key role in the regulation of skeletal muscle substrate utilization. IL-6 is produced in skeletal muscle during exercise in a duration dependent manner and has been reported to increase whole body fatty acid oxidation, muscle glucose uptake and decrease PDHa activity in skeletal muscle of fed mice. The aim of the present study was to examine whether muscle IL-6 contributes to exercise-induced PDH regulation in skeletal muscle. Skeletal muscle-specific IL-6 knockout (IL-6 MKO) mice and floxed littermate controls (control) completed a single bout of treadmill exercise for 10, 60 or 120 min, with rested mice of each genotype serving as basal controls. The respiratory exchange ratio (RER) was overall higher (P<0.05) in IL-6 MKO than control mice during the 120 min of treadmill exercise, while RER decreased during exercise independent of genotype. AMPK and ACC phosphorylation also increased with exercise independent of genotype. PDHa activity was in control mice higher (P<0.05) at 10 and 60 min of exercise than at rest but remained unchanged in IL-6 MKO mice. In addition, PDHa activity was higher (P<0.05) in IL-6 MKO than control mice at rest and 60 min of exercise. Neither PDH phosphorylation nor acetylation could explain the genotype differences in PDHa activity. Together, this provides evidence that skeletal muscle IL-6 contributes to the regulation of PDH at rest and during prolonged exercise and suggests that muscle IL-6 normally dampens carbohydrate utilization during prolonged exercise via effects on PDH.
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Affiliation(s)
- Anders Gudiksen
- Section for cell biology and physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- * E-mail:
| | - Camilla Lindgren Schwartz
- Section for cell biology and physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Lærke Bertholdt
- Section for cell biology and physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Ella Joensen
- Section for cell biology and physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Jakob G. Knudsen
- Section for cell biology and physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Henriette Pilegaard
- Section for cell biology and physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
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Wang Z, Mick GJ, Xie R, Wang X, Xie X, Li G, McCormick KL. Cortisol promotes endoplasmic glucose production via pyridine nucleotide redox. J Endocrinol 2016; 229:25-36. [PMID: 26860459 DOI: 10.1530/joe-16-0006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 02/09/2016] [Indexed: 01/23/2023]
Abstract
Both increased adrenal and peripheral cortisol production, the latter governed by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), contribute to the maintenance of fasting blood glucose. In the endoplasmic reticulum (ER), the pyridine nucleotide redox state (NADP/NADPH) is dictated by the concentration of glucose-6-phosphate (G6P) and the coordinated activities of two enzymes, hexose-6-phosphate dehydrogenase (H6PDH) and 11β-HSD1. However, luminal G6P may similarly serve as a substrate for hepatic glucose-6-phophatase (G6Pase). A tacit belief is that the G6P pool in the ER is equally accessible to both H6PDH and G6Pase. Based on our inhibition studies and kinetic analysis in isolated rat liver microsomes, these two aforesaid luminal enzymes do share the G6P pool in the ER, but not equally. Based on the kinetic modeling of G6P flux, the ER transporter for G6P (T1) preferentially delivers this substrate to G6Pase; hence, the luminal enzymes do not share G6P equally. Moreover, cortisol, acting through 11β-HSD1, begets a more reduced pyridine redox ratio. By altering this luminal redox ratio, G6P flux through H6PDH is restrained, allowing more G6P for the competing enzyme G6Pase. And, at low G6P concentrations in the ER lumen, which occur during fasting, this acute cortisol-induced redox adjustment promotes glucose production. This reproducible cortisol-driven mechanism has been heretofore unrecognized.
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Affiliation(s)
- Zengmin Wang
- Department of PediatricsShandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, PR China Division of Pediatric EndocrinologyUniversity of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Gail J Mick
- Division of Pediatric EndocrinologyUniversity of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Rongrong Xie
- Division of Pediatric EndocrinologyUniversity of Alabama at Birmingham, Birmingham, Alabama, USA Department of EndocrinologyChildren's Hospital of Soochow University, Suzhou, Jiangsu, PR China
| | - Xudong Wang
- Division of Pediatric EndocrinologyUniversity of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Xuemei Xie
- Division of Pediatric EndocrinologyUniversity of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Guimei Li
- Department of PediatricsShandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, PR China
| | - Kenneth L McCormick
- Division of Pediatric EndocrinologyUniversity of Alabama at Birmingham, Birmingham, Alabama, USA
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Li X, Hu G, Li X, Wang YY, Hu YY, Zhou H, Latif SA, Morris DJ, Chu Y, Zheng Z, Ge RS. Metabolic Coupling Determines the Activity: Comparison of 11β-Hydroxysteroid Dehydrogenase 1 and Its Coupling between Liver Parenchymal Cells and Testicular Leydig Cells. PLoS One 2015; 10:e0141767. [PMID: 26528718 PMCID: PMC4631333 DOI: 10.1371/journal.pone.0141767] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 10/13/2015] [Indexed: 11/25/2022] Open
Abstract
Background 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) interconverts active 11β-hydroxyl glucocorticoids and inactive 11keto forms. However, its directionality is determined by availability of NADP+/NADPH. In liver cells, 11β-HSD1 behaves as a primary reductase, while in Leydig cells it acts as a primary oxidase. However, the exact mechanism is not clear. The direction of 11β-HSD1 has been proposed to be regulated by hexose-6-phosphate dehydrogenase (H6PDH), which catalyzes glucose-6-phosphate (G6P) to generate NADPH that drives 11β-HSD1 towards reduction. Methodology To examine the coupling between 11β-HSD1 and H6PDH, we added G6P to rat and human liver and testis or Leydig cell microsomes, and 11β-HSD1 activity was measured by radiometry. Results and Conclusions G6P stimulated 11β-HSD1 reductase activity in rat (3 fold) or human liver (1.5 fold), but not at all in testis. S3483, a G6P transporter inhibitor, reversed the G6P-mediated increases of 11β-HSD1 reductase activity. We compared the extent to which 11β-HSD1 in rat Leydig and liver cells might be coupled to H6PDH. In order to clarify the location of H6PDH within the testis, we used the Leydig cell toxicant ethane dimethanesulfonate (EDS) to selectively deplete Leydig cells. The depletion of Leydig cells eliminated Hsd11b1 (encoding 11β-HSD1) expression but did not affect the expression of H6pd (encoding H6PDH) and Slc37a4 (encoding G6P transporter). H6pd mRNA level and H6PDH activity were barely detectable in purified rat Leydig cells. In conclusion, the availability of H6PDH determines the different direction of 11β-HSD1 in liver and Leydig cells.
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Affiliation(s)
- Xingwang Li
- The Second Affiliated Hospital & Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, ZJ 325000, PR China
| | - Guoxin Hu
- Research Academy of Reproductive Biomedicine, Wenzhou Medical University, Wenzhou, ZJ 325000, PR China
| | - Xiaoheng Li
- Research Academy of Reproductive Biomedicine, Wenzhou Medical University, Wenzhou, ZJ 325000, PR China
| | - Yi-Yan Wang
- The Second Affiliated Hospital & Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, ZJ 325000, PR China
| | - Yuan-Yuan Hu
- The Second Affiliated Hospital & Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, ZJ 325000, PR China
| | - Hongyu Zhou
- Research Academy of Reproductive Biomedicine, Wenzhou Medical University, Wenzhou, ZJ 325000, PR China
| | - Syed A. Latif
- Department of Pathology and Laboratory Medicine, The Miriam Hospital, Brown University School of Medicine, Providence, RI 02906, United States of America
| | - David J. Morris
- Department of Pathology and Laboratory Medicine, The Miriam Hospital, Brown University School of Medicine, Providence, RI 02906, United States of America
| | - Yanhui Chu
- Heilongjiang Key Laboratory of Anti-fibrosis Biotherapy, Mudanjiang Medical University, Mudanjiang, Heilongjiang, PR China
| | - Zhiqiang Zheng
- The Second Affiliated Hospital & Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, ZJ 325000, PR China
- * E-mail: (RG); (ZZ)
| | - Ren-Shan Ge
- The Second Affiliated Hospital & Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, ZJ 325000, PR China
- Research Academy of Reproductive Biomedicine, Wenzhou Medical University, Wenzhou, ZJ 325000, PR China
- Population Council, 1230 York Avenue, New York, NY 10065, United States of America
- * E-mail: (RG); (ZZ)
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Noronha H, Conde C, Delrot S, Gerós H. Identification and functional characterization of grapevine transporters that mediate glucose-6-phosphate uptake into plastids. Planta 2015; 242:909-20. [PMID: 26007686 DOI: 10.1007/s00425-015-2329-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 05/08/2015] [Indexed: 05/28/2023]
Abstract
Two grapevine glucose-6-Pi plastidial transporters differently expressed in plant organs and in response to environmental and hormonal signals are characterized. They are involved in starch accumulation in berries and canes. In grapevine, starch accumulation in the trunk is important for winter storage of carbon and in the flower for reproductive development. Berries also accumulate starch in their plastids, which are also involved in the synthesis of aroma compounds important for fruit quality. The present work characterizes two glucose-phosphate translocators (VvGPT1, VvGPT2) that control the accumulation of starch in grape amyloplasts. Three different splicing variants identified for VvGPT2 (VvGPT2α, VvGPT2β and VvGPT2Ω) were more expressed in the leaves than in other organs. In contrast, VvGPT1 transcripts were more abundant in mature berries, canes and flowers than in the leaves. Expression of 35S-VvGPT1-GFP and 35S-VvGPT2Ω-GFP in tobacco leaf epidermal cells showed that the fusion proteins localized at the plastidial envelope. Complementation of the Arabidopsis pgi1-1 mutant impaired in leaf starch synthesis restored its ability to synthesize starch, demonstrating that VvGPT1 and VvGPT2Ω mediate the transport of glucose-6-Pi across the plastidial envelope. In grape cell suspensions, ABA, light and galactinol, together with sucrose and fructose, significantly increased the transcript abundance of VvGPT1, whereas VvGPT2Ω expression was affected only by sucrose. In addition, elicitation with methyl jasmonate strongly upregulated VvGPT1, VvGPT2Ω and VvPAL1, suggesting a role for GPTs in the production of secondary compounds in grapevine. Moreover, in grapevines cultivated in field conditions, VvGPT1 expression was higher in berries more exposed to the sun and subjected to higher temperatures. Although both VvGPT1 and VvGPT2 mediate the same function at the molecular level, they exhibit different expression levels and regulation in plant organs and in response to environmental and hormonal signals.
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Affiliation(s)
- Henrique Noronha
- Centro de Investigação e de Tecnologias Agro-ambientais e Biológicas CITAB, Vila Real, Portugal
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Dyson BC, Allwood JW, Feil R, Xu Y, Miller M, Bowsher CG, Goodacre R, Lunn JE, Johnson GN. Acclimation of metabolism to light in Arabidopsis thaliana: the glucose 6-phosphate/phosphate translocator GPT2 directs metabolic acclimation. Plant Cell Environ 2015; 38:1404-17. [PMID: 25474495 PMCID: PMC4949648 DOI: 10.1111/pce.12495] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 11/24/2014] [Accepted: 11/25/2014] [Indexed: 05/18/2023]
Abstract
Mature leaves of plants transferred from low to high light typically increase their photosynthetic capacity. In Arabidopsis thaliana, this dynamic acclimation requires expression of GPT2, a glucose 6-phosphate/phosphate translocator. Here, we examine the impact of GPT2 on leaf metabolism and photosynthesis. Plants of wild type and of a GPT2 knockout (gpt2.2) grown under low light achieved the same photosynthetic rate despite having different metabolic and transcriptomic strategies. Immediately upon transfer to high light, gpt2.2 plants showed a higher rate of photosynthesis than wild-type plants (35%); however, over subsequent days, wild-type plants acclimated photosynthetic capacity, increasing the photosynthesis rate by 100% after 7 d. Wild-type plants accumulated more starch than gpt2.2 plants throughout acclimation. We suggest that GPT2 activity results in the net import of glucose 6-phosphate from cytosol to chloroplast, increasing starch synthesis. There was clear acclimation of metabolism, with short-term changes typically being reversed as plants acclimated. Distinct responses to light were observed in wild-type and gpt2.2 leaves. Significantly higher levels of sugar phosphates were observed in gpt2.2. We suggest that GPT2 alters the distribution of metabolites between compartments and that this plays an essential role in allowing the cell to interpret environmental signals.
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Affiliation(s)
- Beth C Dyson
- Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT, UK
| | - J William Allwood
- School of Chemistry and Manchester Institute of Biotechnology, University of Manchester, Manchester, M1 7DN, UK
| | - Regina Feil
- Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam-Golm, Germany
| | - Yun Xu
- School of Chemistry and Manchester Institute of Biotechnology, University of Manchester, Manchester, M1 7DN, UK
| | - Matthew Miller
- Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT, UK
| | - Caroline G Bowsher
- Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT, UK
| | - Royston Goodacre
- School of Chemistry and Manchester Institute of Biotechnology, University of Manchester, Manchester, M1 7DN, UK
| | - John E Lunn
- Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam-Golm, Germany
| | - Giles N Johnson
- Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT, UK
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Li Q, Deng S, Ibarra RA, Anderson VE, Brunengraber H, Zhang GF. Multiple mass isotopomer tracing of acetyl-CoA metabolism in Langendorff-perfused rat hearts: channeling of acetyl-CoA from pyruvate dehydrogenase to carnitine acetyltransferase. J Biol Chem 2015; 290:8121-32. [PMID: 25645937 PMCID: PMC4375469 DOI: 10.1074/jbc.m114.631549] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 01/30/2015] [Indexed: 11/06/2022] Open
Abstract
We developed an isotopic technique to assess mitochondrial acetyl-CoA turnover (≈citric acid flux) in perfused rat hearts. Hearts are perfused with buffer containing tracer [(13)C2,(2)H3]acetate, which forms M5 + M4 + M3 acetyl-CoA. The buffer may also contain one or two labeled substrates, which generate M2 acetyl-CoA (e.g. [(13)C6]glucose or [1,2-(13)C2]palmitate) or/and M1 acetyl-CoA (e.g. [1-(13)C]octanoate). The total acetyl-CoA turnover and the contributions of fuels to acetyl-CoA are calculated from the uptake of the acetate tracer and the mass isotopomer distribution of acetyl-CoA. The method was applied to measurements of acetyl-CoA turnover under different conditions (glucose ± palmitate ± insulin ± dichloroacetate). The data revealed (i) substrate cycling between glycogen and glucose-6-P and between glucose-6-P and triose phosphates, (ii) the release of small excess acetyl groups as acetylcarnitine and ketone bodies, and (iii) the channeling of mitochondrial acetyl-CoA from pyruvate dehydrogenase to carnitine acetyltransferase. Because of this channeling, the labeling of acetylcarnitine and ketone bodies released by the heart are not proxies of the labeling of mitochondrial acetyl-CoA.
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Affiliation(s)
| | | | | | - Vernon E Anderson
- Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
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Kabir AU, Samad MB, Ahmed A, Jahan MR, Akhter F, Tasnim J, Hasan SMN, Sayfe SS, Hannan JMA. Aqueous fraction of Beta vulgaris ameliorates hyperglycemia in diabetic mice due to enhanced glucose stimulated insulin secretion, mediated by acetylcholine and GLP-1, and elevated glucose uptake via increased membrane bound GLUT4 transporters. PLoS One 2015; 10:e0116546. [PMID: 25647228 PMCID: PMC4315578 DOI: 10.1371/journal.pone.0116546] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2014] [Accepted: 12/09/2014] [Indexed: 12/25/2022] Open
Abstract
Background The study was designed to investigate the probable mechanisms of anti-hyperglycemic activity of B. Vulgaris. Methodology/Principal Findings Aqueous fraction of B. Vulgaris extract was the only active fraction (50mg/kg). Plasma insulin level was found to be the highest at 30 mins after B. Vulgaris administration at a dose of 200mg/kg. B. Vulgaris treated mice were also assayed for plasma Acetylcholine, Glucagon Like Peptide-1 (GLP-1), Gastric Inhibitory Peptide (GIP), Vasoactive Intestinal Peptide, Pituitary Adenylate Cyclase-Activating Peptide (PACAP), Insulin Like Growth Factor-1 (IGF-1), Pancreatic Polypeptides (PP), and Somatostatin, along with the corresponding insulin levels. Plasma Acetylcholine and GLP-1 significantly increased in B. Vulgaris treated animals and were further studied. Pharmacological enhancers, inhibitors, and antagonists of Acetylcholine and GLP-1 were also administered to the test animals, and corresponding insulin levels were measured. These studies confirmed the role of acetylcholine and GLP-1 in enhanced insulin secretion (p<0.05). Principal signaling molecules were quantified in isolated mice islets for the respective pathways to elucidate their activities. Elevated concentrations of Acetylcholine and GLP-1 in B. Vulgaris treated mice were found to be sufficient to activate the respective pathways for insulin secretion (p<0.05). The amount of membrane bound GLUT1 and GLUT4 transporters were quantified and the subsequent glucose uptake and glycogen synthesis were assayed. We showed that levels of membrane bound GLUT4 transporters, glucose-6-phosphate in skeletal myocytes, activity of glycogen synthase, and level of glycogen deposited in the skeletal muscles all increased (p<0.05). Conclusion Findings of the present study clearly prove the role of Acetylcholine and GLP-1 in the Insulin secreting activity of B. Vulgaris. Increased glucose uptake in the skeletal muscles and subsequent glycogen synthesis may also play a part in the anti-hyperglycemic activity of B. Vulgaris.
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Affiliation(s)
- Ashraf Ul Kabir
- Department of Pharmaceutical Sciences, North South University, Dhaka, Bangladesh
- * E-mail:
| | - Mehdi Bin Samad
- Department of Pharmaceutical Sciences, North South University, Dhaka, Bangladesh
| | - Arif Ahmed
- Department of Pharmaceutical Sciences, North South University, Dhaka, Bangladesh
| | - Mohammad Rajib Jahan
- Department of Pharmaceutical Sciences, North South University, Dhaka, Bangladesh
| | - Farjana Akhter
- Department of Pharmaceutical Sciences, North South University, Dhaka, Bangladesh
| | - Jinat Tasnim
- Department of Pharmaceutical Sciences, North South University, Dhaka, Bangladesh
| | - S. M. Nageeb Hasan
- Department of Pharmaceutical Sciences, North South University, Dhaka, Bangladesh
| | - Sania Sarker Sayfe
- Pharmacy Discipline, Life Science School, Khulna University, Khulna, Bangladesh
| | - J. M. A. Hannan
- Department of Pharmaceutical Sciences, North South University, Dhaka, Bangladesh
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Brown AM, Ransom BR. Astrocyte glycogen as an emergency fuel under conditions of glucose deprivation or intense neural activity. Metab Brain Dis 2015; 30:233-9. [PMID: 25037166 DOI: 10.1007/s11011-014-9588-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 06/30/2014] [Indexed: 10/24/2022]
Abstract
Energy metabolism in the brain is a complex process that is incompletely understood. Although glucose is agreed as the main energy support of the brain, the role of glucose is not clear, which has led to controversies that can be summarized as follows: the fate of glucose, once it enters the brain is unclear. It is not known the form in which glucose enters the cells (neurons and glia) within the brain, nor the degree of metabolic shuttling of glucose derived metabolites between cells, with a key limitation in our knowledge being the extent of oxidative metabolism, and how increased tissue activity alters this. Glycogen is present within the brain and is derived from glucose. Glycogen is stored in astrocytes and acts to provide short-term delivery of substrates to neural elements, although it may also contribute an important component to astrocyte metabolism. The roles played by glycogen awaits further study, but to date its most important role is in supporting neural elements during increased firing activity, where signaling molecules, proposed to be elevated interstitial K(+), indicative of elevated neural firing rates, activate glycogen phosphorylase leading to increased production of glycogen derived substrate.
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Affiliation(s)
- Angus M Brown
- School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, NG7-2UH, UK,
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