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Su X, You Q, Zhuang L, Chang Z, Ge M, Yang L, Dong WF. Bifunctional electrochemical biosensor based on PB-MXene films for the real-time analysis and detection of living cancer cells. J Pharm Biomed Anal 2023; 234:115479. [PMID: 37454502 DOI: 10.1016/j.jpba.2023.115479] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 05/22/2023] [Accepted: 05/22/2023] [Indexed: 07/18/2023]
Abstract
Circulating tumor cells (CTCs) are important prognostic markers for cancer diagnosis and metastasis, and their detection is an important means to detect cancer metastasis. Herein, we construct a novel bifunctional electrochemical biosensor based on the PB-MXene composite films. A simple electrostatic self-assembly approach was employed to prepare a film composed of PB nanocubes on the MXene substrates. Given that the PB is an artificial peroxidase for H2O2 sensing, the PB-MXene films can realize the real-time monitoring of H2O2 secretion from living CTCs. Besides, the anti-CEA attached biosensors can be utilized to quantify the corresponding CTCs. The synergic effects of the MXene with a large specific area and PB with enzyme-free catalysis for H2O2 resulted in PB-MXene films exhibiting high electrocatalytic and low cytotoxicity for both H2O2 sensing and living CTCs capturing. As a result, the biosensor shows a low detection limit of 0.57 μM towards H2O2 with a wide linear range (1 μM to 500 μM), as well as an excellent sensing performance for CTCs (an extremely low detection limit of 9 cells/mL in a wide linear range of 1.3 ×101 to 1.3 ×106 cells/mL). Moreover, the prepared biosensor showed satisfactory stability and anti-interference ability for potential applications in clinical cancer diagnosis and tumor metastasis.
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Affiliation(s)
- Xue Su
- School of Biomedical Engineering (Suzhou), Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, PR China; Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Science, Suzhou 215163, PR China
| | - Qiannan You
- School of Biomedical Engineering (Suzhou), Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, PR China; Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Science, Suzhou 215163, PR China
| | - Linlin Zhuang
- School of Biomedical Engineering (Suzhou), Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, PR China; Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Science, Suzhou 215163, PR China
| | - Zhimin Chang
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Science, Suzhou 215163, PR China
| | - Mingfeng Ge
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Science, Suzhou 215163, PR China
| | - Li Yang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, PR China.
| | - Wen-Fei Dong
- School of Biomedical Engineering (Suzhou), Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, PR China; Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Science, Suzhou 215163, PR China.
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Mencke P, Boussaad I, Romano CD, Kitami T, Linster CL, Krüger R. The Role of DJ-1 in Cellular Metabolism and Pathophysiological Implications for Parkinson's Disease. Cells 2021; 10:347. [PMID: 33562311 PMCID: PMC7915027 DOI: 10.3390/cells10020347] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 01/27/2021] [Accepted: 02/03/2021] [Indexed: 11/16/2022] Open
Abstract
DJ-1 is a multifunctional protein associated with pathomechanisms implicated in different chronic diseases including neurodegeneration, cancer and diabetes. Several of the physiological functions of DJ-1 are not yet fully understood; however, in the last years, there has been increasing evidence for a potential role of DJ-1 in the regulation of cellular metabolism. Here, we summarize the current knowledge on specific functions of DJ-1 relevant to cellular metabolism and their role in modulating metabolic pathways. Further, we illustrate pathophysiological implications of the metabolic effects of DJ-1 in the context of neurodegeneration in Parkinson´s disease.
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Affiliation(s)
- Pauline Mencke
- Translational Neuroscience, Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 4365 Esch-sur-Alzette, Luxembourg;
| | - Ibrahim Boussaad
- Translational Neuroscience, Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 4365 Esch-sur-Alzette, Luxembourg;
| | - Chiara D. Romano
- Biospecimen Research Group, Integrated Biobank of Luxembourg, Luxembourg Institute of Health (LIH), 3531 Dudelange, Luxembourg;
- Enzymology & Metabolism, Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 4365 Esch-sur-Alzette, Luxembourg;
| | - Toshimori Kitami
- RIKEN Outpost Laboratory, Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 4365 Esch-sur-Alzette, Luxembourg;
| | - Carole L. Linster
- Enzymology & Metabolism, Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 4365 Esch-sur-Alzette, Luxembourg;
| | - Rejko Krüger
- Translational Neuroscience, Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 4365 Esch-sur-Alzette, Luxembourg;
- Parkinson Research Clinic, Centre Hospitalier de Luxembourg (CHL), 1210 Luxembourg (Belair), Luxembourg
- Transversal Translational Medicine, Luxembourg Institute of Health (LIH), 1445 Strassen, Luxembourg
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3
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Cell-to-cell lactate shuttle operates in heart and is important in age-related heart failure. Aging (Albany NY) 2020; 12:3388-3406. [PMID: 32035422 PMCID: PMC7066931 DOI: 10.18632/aging.102818] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 01/27/2020] [Indexed: 01/02/2023]
Abstract
Recent studies have revealed a resemblance of a HIF-regulated heart and brain glycolytic profiles prompting the hypothesis that the classical cell-to-cell lactate shuttle observed between astrocytes and neurons operates also in heart - between cardiac fibroblasts and cardiomyocytes. Here, we demonstrate that co-culturing of cardiomyocytes with cardiac fibroblasts leads to orchestrated changes in expression and/or localization pattern of glucose metabolism enzymes and lactate transport proteins in both cell types. These changes are regulated by paracrine signaling using microvesicle-packed and soluble factors released to the culture medium and, taken together, they concur with the cardiac lactate shuttle hypothesis. The results presented here show that similarity of heart and brain proteomes demonstrated earlier extend to physiological level and provide a theoretical rationale for designing novel therapeutic strategies for treatment of cardiomyopathies resulting from disruption of the maturation of cardiac metabolic pathways, and of heart failure associated with metabolic complications and age-related heart failure linked with extracellular matrix deposition and hypoxia.
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Gonzalez-Menendez P, Hevia D, Alonso-Arias R, Alvarez-Artime A, Rodriguez-Garcia A, Kinet S, Gonzalez-Pola I, Taylor N, Mayo JC, Sainz RM. GLUT1 protects prostate cancer cells from glucose deprivation-induced oxidative stress. Redox Biol 2018; 17:112-127. [PMID: 29684818 PMCID: PMC6007175 DOI: 10.1016/j.redox.2018.03.017] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 03/20/2018] [Accepted: 03/26/2018] [Indexed: 01/02/2023] Open
Abstract
Glucose, chief metabolic support for cancer cell survival and growth, is mainly imported into cells by facilitated glucose transporters (GLUTs). The increase in glucose uptake along with tumor progression is due to an increment of facilitative glucose transporters as GLUT1. GLUT1 prevents cell death of cancer cells caused by growth factors deprivation, but there is scarce information about its role on the damage caused by glucose deprivation, which usually occurs within the core of a growing tumor. In prostate cancer (PCa), GLUT1 is found in the most aggressive tumors, and it is regulated by androgens. To study the response of androgen-sensitive and insensitive PCa cells to glucose deprivation and the role of GLUT1 on survival mechanisms, androgen-sensitive LNCaP and castration-resistant LNCaP-R cells were employed. Results demonstrated that glucose deprivation induced a necrotic type of cell death which is prevented by antioxidants. Androgen-sensitive cells show a higher resistance to cell death triggered by glucose deprivation than castration-resistant cells. Glucose removal causes an increment of H2O2, an activation of androgen receptor (AR) and a stimulation of AMP-activated protein kinase activity. In addition, glucose removal increases GLUT1 production in androgen sensitive PCa cells. GLUT1 ectopic overexpression makes PCa cells more resistant to glucose deprivation and oxidative stress-induced cell death. Under glucose deprivation, GLUT1 overexpressing PCa cells sustains mitochondrial SOD2 activity, compromised after glucose removal, and significantly increases reduced glutathione (GSH). In conclusion, androgen-sensitive PCa cells are more resistant to glucose deprivation-induced cell death by a GLUT1 upregulation through an enhancement of reduced glutathione levels. Glucose deprivation carries an increase of free radicals in prostate cancer cells. The androgen receptor activation after glucose deprivation proceeds with GLUT1 overproduction. Treatment with hydrogen peroxide mimics the response to glucose deprivation. GLUT1-overexpressing prostate cancer cells are more resistant to glucose deprivation. Glutathione is more reduced in GLUT1-overexpressing cells under glucose deprivation.
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Affiliation(s)
- Pedro Gonzalez-Menendez
- Department of Morphology and Cell Biology, Redox Biology Unit. University Institute of Oncology of Asturias (IUOPA), University of Oviedo. Facultad de Medicina, Julián Clavería 6, 33006 Oviedo, Spain
| | - David Hevia
- Department of Morphology and Cell Biology, Redox Biology Unit. University Institute of Oncology of Asturias (IUOPA), University of Oviedo. Facultad de Medicina, Julián Clavería 6, 33006 Oviedo, Spain
| | - Rebeca Alonso-Arias
- Department of Immunology, Hospital Universitario Central de Asturias (HUCA), Avenida de Roma, 33011 Oviedo, Spain
| | - Alejandro Alvarez-Artime
- Department of Morphology and Cell Biology, Redox Biology Unit. University Institute of Oncology of Asturias (IUOPA), University of Oviedo. Facultad de Medicina, Julián Clavería 6, 33006 Oviedo, Spain
| | - Aida Rodriguez-Garcia
- Department of Microbiology, Tumor, and Cell Biology (MTC), Karolinska Institute, Tomtebodavägen 12C, Iastkajen, 171 65 Stockholm, Sweden
| | - Sandrina Kinet
- Institut de Genetique Moleculaire de Montpellier, Centre National de la Recherche Scientifique UMR5535, Universite de Montpellier 1 et 2, F-34293 Montpellier, France; Laboratory of Excellence GR-Ex, Paris 75015, France
| | - Ivan Gonzalez-Pola
- Department of Morphology and Cell Biology, Redox Biology Unit. University Institute of Oncology of Asturias (IUOPA), University of Oviedo. Facultad de Medicina, Julián Clavería 6, 33006 Oviedo, Spain
| | - Naomi Taylor
- Institut de Genetique Moleculaire de Montpellier, Centre National de la Recherche Scientifique UMR5535, Universite de Montpellier 1 et 2, F-34293 Montpellier, France; Laboratory of Excellence GR-Ex, Paris 75015, France
| | - Juan C Mayo
- Department of Morphology and Cell Biology, Redox Biology Unit. University Institute of Oncology of Asturias (IUOPA), University of Oviedo. Facultad de Medicina, Julián Clavería 6, 33006 Oviedo, Spain.
| | - Rosa M Sainz
- Department of Morphology and Cell Biology, Redox Biology Unit. University Institute of Oncology of Asturias (IUOPA), University of Oviedo. Facultad de Medicina, Julián Clavería 6, 33006 Oviedo, Spain.
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5
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Requejo-Aguilar R, Bolaños JP. Mitochondrial control of cell bioenergetics in Parkinson's disease. Free Radic Biol Med 2016; 100:123-137. [PMID: 27091692 PMCID: PMC5065935 DOI: 10.1016/j.freeradbiomed.2016.04.012] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 04/13/2016] [Accepted: 04/14/2016] [Indexed: 12/15/2022]
Abstract
Parkinson disease (PD) is a neurodegenerative disorder characterized by a selective loss of dopaminergic neurons in the substantia nigra. The earliest biochemical signs of the disease involve failure in mitochondrial-endoplasmic reticulum cross talk and lysosomal function, mitochondrial electron chain impairment, mitochondrial dynamics alterations, and calcium and iron homeostasis abnormalities. These changes are associated with increased mitochondrial reactive oxygen species (mROS) and energy deficiency. Recently, it has been reported that, as an attempt to compensate for the mitochondrial dysfunction, neurons invoke glycolysis as a low-efficient mode of energy production in models of PD. Here, we review how mitochondria orchestrate the maintenance of cellular energetic status in PD, with special focus on the switch from oxidative phosphorylation to glycolysis, as well as the implication of endoplasmic reticulum and lysosomes in the control of bioenergetics.
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Affiliation(s)
- Raquel Requejo-Aguilar
- Department of Biochemistry and Molecular Biology, University of Cordoba, Institute Maimonides of Biomedical Investigation of Cordoba (IMIBIC), Cordoba, Spain
| | - Juan P Bolaños
- Institute of Functional Biology and Genomics (IBFG), University of Salamanca-CSIC, Zacarias Gonzalez, 2, 37007 Salamanca, Spain.
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6
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Liemburg-Apers DC, Willems PHGM, Koopman WJH, Grefte S. Interactions between mitochondrial reactive oxygen species and cellular glucose metabolism. Arch Toxicol 2015; 89:1209-26. [PMID: 26047665 PMCID: PMC4508370 DOI: 10.1007/s00204-015-1520-y] [Citation(s) in RCA: 248] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 04/27/2015] [Indexed: 12/20/2022]
Abstract
Mitochondrial reactive oxygen species (ROS) production and detoxification are tightly balanced. Shifting this balance enables ROS to activate intracellular signaling and/or induce cellular damage and cell death. Increased mitochondrial ROS production is observed in a number of pathological conditions characterized by mitochondrial dysfunction. One important hallmark of these diseases is enhanced glycolytic activity and low or impaired oxidative phosphorylation. This suggests that ROS is involved in glycolysis (dys)regulation and vice versa. Here we focus on the bidirectional link between ROS and the regulation of glucose metabolism. To this end, we provide a basic introduction into mitochondrial energy metabolism, ROS generation and redox homeostasis. Next, we discuss the interactions between cellular glucose metabolism and ROS. ROS-stimulated cellular glucose uptake can stimulate both ROS production and scavenging. When glucose-stimulated ROS production, leading to further glucose uptake, is not adequately counterbalanced by (glucose-stimulated) ROS scavenging systems, a toxic cycle is triggered, ultimately leading to cell death. Here we inventoried the various cellular regulatory mechanisms and negative feedback loops that prevent this cycle from occurring. It is concluded that more insight in these processes is required to understand why they are (un)able to prevent excessive ROS production during various pathological conditions in humans.
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Affiliation(s)
- Dania C. Liemburg-Apers
- />Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences (RIMLS), Radboud University Medical Center (RUMC), P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Peter H. G. M. Willems
- />Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences (RIMLS), Radboud University Medical Center (RUMC), P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Werner J. H. Koopman
- />Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences (RIMLS), Radboud University Medical Center (RUMC), P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Sander Grefte
- />Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences (RIMLS), Radboud University Medical Center (RUMC), P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
- />Department of Human and Animal Physiology, Wageningen University, P.O. Box 338, 6700 AH Wageningen, The Netherlands
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7
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De Bock M, Decrock E, Wang N, Bol M, Vinken M, Bultynck G, Leybaert L. The dual face of connexin-based astroglial Ca(2+) communication: a key player in brain physiology and a prime target in pathology. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:2211-32. [PMID: 24768716 DOI: 10.1016/j.bbamcr.2014.04.016] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 04/11/2014] [Accepted: 04/12/2014] [Indexed: 12/21/2022]
Abstract
For decades, studies have been focusing on the neuronal abnormalities that accompany neurodegenerative disorders. Yet, glial cells are emerging as important players in numerous neurological diseases. Astrocytes, the main type of glia in the central nervous system , form extensive networks that physically and functionally connect neuronal synapses with cerebral blood vessels. Normal brain functioning strictly depends on highly specialized cellular cross-talk between these different partners to which Ca(2+), as a signaling ion, largely contributes. Altered intracellular Ca(2+) levels are associated with neurodegenerative disorders and play a crucial role in the glial responses to injury. Intracellular Ca(2+) increases in single astrocytes can be propagated toward neighboring cells as intercellular Ca(2+) waves, thereby recruiting a larger group of cells. Intercellular Ca(2+) wave propagation depends on two, parallel, connexin (Cx) channel-based mechanisms: i) the diffusion of inositol 1,4,5-trisphosphate through gap junction channels that directly connect the cytoplasm of neighboring cells, and ii) the release of paracrine messengers such as glutamate and ATP through hemichannels ('half of a gap junction channel'). This review gives an overview of the current knowledge on Cx-mediated Ca(2+) communication among astrocytes as well as between astrocytes and other brain cell types in physiology and pathology, with a focus on the processes of neurodegeneration and reactive gliosis. Research on Cx-mediated astroglial Ca(2+) communication may ultimately shed light on the development of targeted therapies for neurodegenerative disorders in which astrocytes participate. This article is part of a Special Issue entitled: Calcium signaling in health and disease. Guest Editors: Geert Bultynck, Jacques Haiech, Claus W. Heizmann, Joachim Krebs, and Marc Moreau.
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Affiliation(s)
- Marijke De Bock
- Department of Basic Medical Sciences, Physiology group, Faculty of Medicine and Health Sciences, Ghent University, B-9000 Ghent, Belgium
| | - Elke Decrock
- Department of Basic Medical Sciences, Physiology group, Faculty of Medicine and Health Sciences, Ghent University, B-9000 Ghent, Belgium.
| | - Nan Wang
- Department of Basic Medical Sciences, Physiology group, Faculty of Medicine and Health Sciences, Ghent University, B-9000 Ghent, Belgium
| | - Mélissa Bol
- Department of Basic Medical Sciences, Physiology group, Faculty of Medicine and Health Sciences, Ghent University, B-9000 Ghent, Belgium
| | - Mathieu Vinken
- Department of Toxicology, Center for Pharmaceutical Research, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, B-1090 Brussels, Belgium
| | - Geert Bultynck
- Department of Cellular and Molecular Medicine, Laboratory of Molecular and Cellular Signalling, KULeuven, Campus Gasthuisberg O/N-I bus 802, B-3000 Leuven, Belgium
| | - Luc Leybaert
- Department of Basic Medical Sciences, Physiology group, Faculty of Medicine and Health Sciences, Ghent University, B-9000 Ghent, Belgium
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Maraldi T, Prata C, Fiorentini D, Zambonin L, Landi L, Hakim G. Signal processes and ROS production in glucose transport regulation by thrombopoietin and granulocyte macrophage-colony stimulation factor in a human leukaemic cell line. Free Radic Res 2009; 41:1348-57. [DOI: 10.1080/10715760701730347] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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9
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Sahu SC, Garthoff LH, Robl MG, Chirtel SJ, Ruggles DI, Flynn TJ, Sobotka TJ. Rat liver clone-9 cells in culture as a model for screening hepatotoxic potential of food-related products: hepatotoxicity of deoxynivalenol. J Appl Toxicol 2008; 28:765-72. [DOI: 10.1002/jat.1337] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Subramanya S, Mensa-Wilmot K. Regulated cleavage of intracellular glycosylphosphatidylinositol in a trypanosome. Peroxisome-to-endoplasmic reticulum translocation of a phospholipase C. FEBS J 2006; 273:2110-26. [PMID: 16649989 DOI: 10.1111/j.1742-4658.2006.05225.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cell exposure to hypo-osmolarity and alkalinity triggers a spectrum of responses including activation of phospholipases. Glycosylphosphatidylinositol-specific phospholipase C (GPI-PLC) is expressed in Trypanosoma brucei, a protozoan parasite that causes human African trypanosomiasis. We examined possible contributions of GPI-PLC to the response of T. brucei to hypo-osmotic or mildly alkaline conditions. GPIs were detected at the endoplasmic reticulum (ER). They were cleaved after exposure of T. brucei to hypo-osmolarity or mild alkalinity, which also, strikingly, caused translocation of GPI-PLC from glycosomes (peroxisomes) to the ER. A catalytically inactive Gln81Leu mutant of GPI-PLC failed to cleave GPIs despite being transported from glycosomes to the ER after hypo-osmotic or mild alkaline treatment of the parasites. In contrast, a Cys347Ser mutant of the enzyme could not exit glycosomes after treatment of cells expressing the protein with mild base or hypo-osmotic buffer. We conclude that: (a) GPI-PLC contributes to loss of GPIs in T. brucei treated with hypo-osmotic or mildly alkaline buffer; (b) access of GPI-PLC to its substrate in vivo can be regulated post-translationally; (c) translocation of GPI-PLC from glycosomes to the ER is important for in vivo cleavage of GPIs; (d) Cys347 is part of a peptide motif required for post-translational targeting of GPI-PLC to the ER. Glycosome-to-ER movement of GPI-PLC reveals a novel pathway for intracellular protein traffic. The physiological significance of GPI digestion in cells exposed to mildly alkalinity or hypo-osmolarity is discussed.
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Affiliation(s)
- Sandesh Subramanya
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
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Jing M, Ismail-Beigi F. Role of 5'-AMP-activated protein kinase in stimulation of glucose transport in response to inhibition of oxidative phosphorylation. Am J Physiol Cell Physiol 2005; 290:C484-91. [PMID: 16162657 DOI: 10.1152/ajpcell.00321.2005] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glucose transport is stimulated in a variety of cells and tissues in response to inhibition of oxidative phosphorylation. However, the underlying mechanisms and mediating steps remain largely unknown. In the present study we first tested whether a decrease in the redox state of the cell per se and the resultant increase in generation of reactive oxygen species (ROS) lead to stimulation of glucose transport. Clone 9 cells (expressing the Glut1 isoform of facilitative glucose transporters) were exposed to azide, lactate, and ethanol for 1 h. Although all three agents stimulated glucose transport and increased cell NADH-to-NAD(+) ratio and phospho-ERK1/2, signifying increased ROS generation, the response to the stimuli was not blocked by N-acetyl-l-cysteine (an agent that counteracts ROS); moreover, the response to azide was not blocked by diamide (an intracellular sulfhydryl oxidizing agent). We then found that cell AMP-to-ATP and ADP-to-ATP ratios were increased and 5'-AMP-activated protein kinase (AMPK) was stimulated by all three agents, as evidenced by increased phosphorylation of AMPK and acetyl-CoA carboxylase. We conclude that although azide, lactate, and ethanol increase NADH-to-NAD(+) ratios and ROS production, their stimulatory effect on glucose transport is not mediated by increased ROS generation. However, all three agents increased cell AMP-to-ATP ratio and stimulated AMPK, making it likely that the latter pathway plays an important role in the glucose transport response.
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Affiliation(s)
- Ming Jing
- Department of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-4951, USA
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12
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Agnetti G, Maraldi T, Fiorentini D, Giordano E, Prata C, Hakim G, Muscari C, Guarnieri C, Caldarera CM. Activation of glucose transport during simulated ischemia in H9c2 cardiac myoblasts is mediated by protein kinase C isoforms. Life Sci 2005; 78:264-70. [PMID: 16111715 DOI: 10.1016/j.lfs.2005.04.039] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2004] [Accepted: 04/20/2005] [Indexed: 11/25/2022]
Abstract
Glucose transport into cells may be regulated by a variety of conditions, including ischemia. We investigated whether some enzymes frequently involved in the metabolic adaptation to ischemia are also required for glucose transport activation. Ischemia was simulated by incubating during 3 h H9c2 cardiomyoblasts in a serum- and glucose-free medium in hypoxia. Under these conditions 2-deoxy-d-[2,6-(3)H]-glucose uptake was increased (57% above control levels, p<0.0001) consistently with GLUT1 and GLUT4 translocation to sarcolemma. Tyrosine kinases inhibition via tyrphostin had no effect on glucose transport up-regulation induced by simulated ischemia. On the other hand, chelerythrine, a broad range inhibitor of protein kinase C isoforms, and rottlerin, an inhibitor of protein kinase C delta, completely prevented the stimulation of the transport rate. A lower activation of hexose uptake (19%, p<0.001) followed also treatment with Gö6976, an inhibitor of conventional protein kinases C. Finally, PD98059-mediated inhibition of the phosphorylation of ERK 1/2, a downstream mitogen-activated protein kinase (MAPK), only partially reduced the activation of glucose transport induced by simulated ischemia (31%, p<0.01), while SB203580, an inhibitor of p38 MAPK, did not exert any effect. These results indicate that stimulation of protein kinase C delta is strongly related to the up-regulation of glucose transport induced by simulated ischemia in cultured cardiomyoblasts and that conventional protein kinases C and ERK 1/2 are partially involved in the signalling pathways mediating this process.
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Affiliation(s)
- Giulio Agnetti
- Department of Biochemistry "G. Moruzzi", University of Bologna, Via Irnerio 48, 40126 Bologna, Italy.
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13
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Abstract
Neurovascular and neurometabolic coupling help the brain to maintain an appropriate energy flow to the neural tissue under conditions of increased neuronal activity. Both coupling phenomena provide us, in addition, with two macroscopically measurable parameters, blood flow and intermediate metabolite fluxes, that are used to dynamically image the functioning brain. The main energy substrate for the brain is glucose, which is metabolized by glycolysis and oxidative breakdown in both astrocytes and neurons. Neuronal activation triggers increased glucose consumption and glucose demand, with new glucose being brought in by stimulated blood flow and glucose transport over the blood-brain barrier. Glucose is shuttled over the barrier by the GLUT-1 transporter, which, like all transporter proteins, has a ceiling above which no further stimulation of the transport is possible. Blood-brain barrier glucose transport is generally accepted as a nonrate-limiting step but to prevent it from becoming rate-limiting under conditions of neuronal activation, it might be necessary for the transport parameters to be adapted to the increased glucose demand. It is proposed that the blood-brain barrier glucose transport parameters are dynamically adapted to the increased glucose needs of the neural tissue after activation according to a neurobarrier coupling scheme. This review presents neurobarrier coupling within the current knowledge on neurovascular and neurometabolic coupling, and considers arguments and evidence in support of this hypothesis.
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Affiliation(s)
- Luc Leybaert
- Department of Physiology and Pathophysiology, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.
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Yu PH, Wang M, Fan H, Deng Y, Gubisne-Haberle D. Involvement of SSAO-mediated deamination in adipose glucose transport and weight gain in obese diabetic KKAy mice. Am J Physiol Endocrinol Metab 2004; 286:E634-41. [PMID: 14656718 DOI: 10.1152/ajpendo.00272.2003] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Semicarbazide-sensitive amine oxidase (SSAO) is located on outer surfaces of adipocytes and endothelial and vascular smooth muscle cells. This enzyme catalyzes deamination of methylamine and aminoacetone, leading to production of toxic formaldehyde and methylglyoxal, respectively, as well as hydrogen peroxide and ammonium. Several lines of evidence suggest that increased SSAO activity is related to chronic inflammation and vascular disorders related to diabetic complications. We found that a highly potent and selective SSAO inhibitor, (E)-2-(4-fluorophenethyl)-3-fluoroallylamine (FPFA), was capable of reducing numbers of atherosclerotic lesions as well as weight gain in obese KKAy mice fed an atherogenic diet. SSAO inhibitors cause a moderate and long-lasting hyperglycemia. Such an increase in serum glucose is a result of reduction of glucose uptake by adipocytes. SSAO-mediated deamination of endogenous methylamine substrates induces adipocyte glucose uptake and lipogenesis. Highly selective SSAO inhibitors can effectively block induced glucose uptake. The results suggest that increased SSAO-mediated deamination may be concomitantly related to obesity and vascular disorders associated with type 2 diabetes.
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Affiliation(s)
- Peter H Yu
- Neuropsychiatry Research Unit, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E4
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15
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Maraldi T, Fiorentini D, Prata C, Landi L, Hakim G. Stem cell factor and H2O2 induce GLUT1 translocation in M07e cells. Biofactors 2004; 20:97-108. [PMID: 15322333 DOI: 10.1002/biof.5520200204] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This work aims to elucidate the mechanisms involved in the early activation of glucose transport in hematopoietic M07e cells by stem cell factor (SCF) and a reactive oxygen species (ROS) as H2O2. SCF and H2O2 increase Vmax for glucose transport; this enhancement is due to a higher content in GLUT1 in plasma membranes, possibly through a translocation from intracellular stores. Inhibitors of tyrosine kinases or phospholipase C (PLC) remove glucose transport enhancement and prevent translocation. The inhibitory effect of STI-571 suggests a role for c-kit tyrosine kinase on glucose transport activation not only by SCF, but also by H2O2. On the other hand, neither protein kinase C nor phosphoinositide-3-kinase appear to be involved in the acute activation of glucose transport. Our data suggest that i) in M07e cells, SCF and exogenous H2O2 elicit a short-term activation of glucose transport through a translocation of GLUT1 from intracellular stores to plasma membranes; ii) both stimuli could share at least some signaling pathways leading to glucose uptake activation, involving protein tyrosine kinases and PLC iii) H2O2 could act increasing the level of tyrosine phosphorylation through the inhibition of tyrosine phosphatases and mimicking the regulation role of endogenous ROS.
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Affiliation(s)
- Tullia Maraldi
- Dipartimento di Biochimica G. Moruzzi, Università di Bologna, Via Irnerio 48, I-40126 Bologna, Italy
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16
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Glutamate triggers rapid glucose transport stimulation in astrocytes as evidenced by real-time confocal microscopy. J Neurosci 2003. [PMID: 12917367 DOI: 10.1523/jneurosci.23-19-07337.2003] [Citation(s) in RCA: 182] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Glutamate stimulates glycolysis in astrocytes, a phenomenon that couples astrocytic metabolism with neuronal activity. However, it is not known whether glutamate also affects glucose transporter-1 (GLUT1), the transporter responsible for glucose entry into astrocytes. To address this question, two different real-time single-cell hexose uptake assays were applied to cultured hippocampal astrocytes using confocal epifluorescence microscopy. Glutamate caused a twofold to threefold increase in the zero-trans uptake rates of the fluorescent hexoses 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxyglucose (2-NBDG) and 6-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-6-deoxyglucose (6-NBDG). Galactose uptake, determined by the calcein volumetric assay, was stimulated to a similar extent, confirming the fluorescent hexose data, and also demonstrating that glutamate stimulation is a Vmax effect. Remarkably, glucose transport stimulation developed fully inside 10 sec, which is 100 times faster than acute stimulations of glucose transport in other cell types. Glutamate did not significantly affect the rate of 6-NBDG uptake by GLUT1-expressing epithelial Clone 9 cells, suggesting that an astrocyte-specific factor is required for transport stimulation. We conclude that glucose transport stimulation occurs early during astrocytic activation by glutamate, which provides a novel regulatory node to current models of brain energy metabolism. This mechanism should also be considered for the interpretation of functional imaging data based on hexoses.
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17
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Rubin D, Ismail-Beigi F. Distribution of Glut1 in detergent-resistant membranes (DRMs) and non-DRM domains: effect of treatment with azide. Am J Physiol Cell Physiol 2003; 285:C377-83. [PMID: 12686514 DOI: 10.1152/ajpcell.00060.2003] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have previously shown that the acute stimulation of glucose transport in Clone 9 cells in response to azide is mediated by activation of Glut1 and that stomatin, a Glut1-binding protein, appears to inhibit Glut1 function. In Clone 9 cells under basal conditions, approximately 38% of Glut1, approximately 70% of stomatin, and the bulk of caveolin-1 was localized in the detergent-resistant membrane (DRM) fraction; a significant fraction of Glut1 is also present in DRMs of 3T3-L1 fibroblasts and human red blood cells (RBCs). Acute exposure to azide resulted in 40 and 50% decreases in the content of Glut1 in DRMs of Clone 9 cells and 3T3-L1 fibroblasts, respectively, whereas the distribution of stomatin and caveolin-1 in Clone 9 cells remained unchanged. In addition, treatment of Clone 9 cells with azide resulted in a approximately 50% decrease in the content of Glut1 in the DRM fraction of plasma membranes. We conclude that 1) a significant fraction of Glut1 is localized in DRMs, and 2) treatment of cells with azide results in a partial redistribution of Glut1 out of the DRM fraction.
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Affiliation(s)
- Darrell Rubin
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106-4951, USA
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18
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Orzechowski A. Justification for antioxidant preconditioning (or how to protect insulin-mediated actions under oxidative stress). J Biosci 2003; 28:39-49. [PMID: 12682423 DOI: 10.1007/bf02970130] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Insulin resistance is characterized by impaired glucose utilization in the peripheral tissues, accelerated muscle protein degradation, impaired antioxidant defences and extensive cell death. Apparently, both insulin and IGF-1 at physiological concentrations support cell survival by phosphatidylinositol 3 kinase-dependent and independent mechanisms. Postprandial hyperglycemia and hyperinsulinemia are found in insulin resistance, which accompanies the so-called noninsulin dependent diabetes mellitus (diabetes type 2). Evidence also indicates that increased susceptibility of muscle cells and cardiomycoytes to oxidative stress is among the harmful complications of insulin resistance and diabetes. Limited knowledge showing benefits of preconditioning with anti- oxidants (vitamin C, E, a-lipoic acid, N-acetylcysteine) in order to protect insulin action under oxidative stress prompted the author to discuss the theoretical background to this approach. It should be stressed that antioxidant preconditioning is relevant to prevention of both diabetes- and insulin resistance-associated side-effects such as low viability and cell deletion. Furthermore, antioxidant conditioning promises to provide higher efficacy for clinical applications in myoblast transfer therapy and cardiomyoplasty.
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Affiliation(s)
- A Orzechowski
- Department of Physiological Sciences, Faculty of Veterinary Medicine, Warsaw Agricultural University, 02-787 Warsaw, Nowoursynowska 159, Poland.
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19
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Hrelia S, Fiorentini D, Maraldi T, Angeloni C, Bordoni A, Biagi PL, Hakim G. Doxorubicin induces early lipid peroxidation associated with changes in glucose transport in cultured cardiomyocytes. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1567:150-6. [PMID: 12488048 DOI: 10.1016/s0005-2736(02)00612-0] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Doxorubicin (DOX) has not only chronic, but also acute toxic effects in the heart, ascribed to the generation of reactive oxygen species (ROS). Focusing on the DOX-induced early biochemical changes in rat cardiomyocytes, we demonstrated that lipid peroxidation is an early event, in fact conjugated diene production increased after 1-h DOX exposure, while cell damage, evaluated as lactate dehydrogenase (LDH) release, was observed only later, when at least one third of the cell antioxidant defences were consumed. Cell pre-treatment with alpha-tocopherol (TC) inhibited both conjugated diene production and LDH release. In cardiomyocytes, DOX treatment caused a maximal increase in glucose uptake at 1 h, demonstrating that glucose transport may represent an early target for DOX. At longer times, as the cell damage become significant, the glucose uptake stimulation diminished. Immunoblotting of glucose transporter isoform GLUT1 in membranes after 1-h DOX exposure revealed an increase in GLUT1 amount similar to the increase in transport activity; both effects were inhibited by alpha TC. Early lipid peroxidation evokes an adaptive response resulting in an increased glucose uptake, presumably to restore cellular energy. The regulation of nutrient transport mechanisms in cardiomyocytes may be considered an early event in the development of the cardiotoxic effects of the anthracycline.
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Affiliation(s)
- Silvana Hrelia
- Department of Biochemistry G. Moruzzi, University of Bologna, Via Irnerio 48, I-40126 Bologna, Italy.
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20
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Patel S, Van Der Kaay J, Sutherland C. Insulin regulation of hepatic insulin-like growth factor-binding protein-1 (IGFBP-1) gene expression and mammalian target of rapamycin (mTOR) signalling is impaired by the presence of hydrogen peroxide. Biochem J 2002; 365:537-45. [PMID: 11942857 PMCID: PMC1222689 DOI: 10.1042/bj20020266] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2002] [Revised: 03/27/2002] [Accepted: 04/10/2002] [Indexed: 11/17/2022]
Abstract
Hepatic expression of insulin-like growth factor-binding protein-1 (IGFBP-1) is rapidly and completely inhibited by insulin. The signalling pathway that mediates this effect of insulin requires the activation of phosphoinositide 3-kinase (PI 3-kinase). Many of the cellular actions of insulin, including activation of PI 3-kinase, can be 'mimicked' by oxidative stresses, such as H(2)O(2). In the present study, we demonstrate that H(2)O(2) does not 'mimic' but rather antagonizes insulin repression of IGFBP-1 gene expression in H4IIE cells. This effect is accompanied by a decrease in the insulin-induced activation of mammalian target of rapamycin (mTOR)-dependent signalling. However, insulin-induced phosphorylation and regulation of protein kinase B, glycogen synthase kinase-3 and FKHR (forkhead in rhabdomyosarcoma) are not affected by H(2)O(2) in the same cells. In addition, H(2)O(2) strongly activates the p42/p44 mitogen-activated protein kinases, but the presence of PD184352 (an inhibitor of this pathway) does not block the effect of H(2)O(2) on IGFBP-1 gene expression. Our results support the view that the insulin-mediated repression of IGFBP-1 gene expression is partly mTOR-dependent, and demonstrate that H(2)O(2) selectively antagonizes mTOR-dependent insulin action. The implications for the use of H(2)O(2)-generating agents as therapeutics for the treatment of insulin resistance, as well as the role of oxidative stress in the development of insulin resistance, are discussed.
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Affiliation(s)
- Satish Patel
- Department of Pharmacology and Neurosciences, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK.
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21
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Hwang DY, Ismail-Beigi F. Glucose uptake and lactate production in cells exposed to CoCl(2) and in cells overexpressing the Glut-1 glucose transporter. Arch Biochem Biophys 2002; 399:206-11. [PMID: 11888207 DOI: 10.1006/abbi.2002.2758] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glut-1-mediated glucose transport is augmented in response to a variety of conditions and stimuli. In this study we examined the metabolic fate of glucose in cells in which glucose transport is stimulated by exposure to CoCl(2), an agent that stimulates the expression of a set of hypoxia-responsive genes including several glycolytic enzymes and the Glut-1 glucose transporter. Similarly, we determined the metabolic fate of glucose in stably transfected cells overexpressing Glut-1. Exposure of Clone 9 liver cell line, 3T3-L1 fibroblasts, and C(2)C(12) myoblasts to CoCl(2) resulted in an increase glucose uptake and in the activity of glucose phosphorylation ("hexokinase") and lactate dehydrogenase. In cells treated with CoCl(2), the net increase in glucose taken up was accounted for by its near-complete conversion to lactate. Cells stably transfected to overexpress Glut-1 also exhibited enhanced net uptake of glucose with the near-complete conversion of the increased glucose taken up to lactate; however, the effect in these cells was observed in the absence of any change in the activity of two glycolytic enzymes examined. These findings suggest that in cells in which glucose transport is rate-limiting for glucose metabolism, enhancement of the glucose entry step per se results in a near-complete conversion of the extra glucose to lactate.
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Affiliation(s)
- Daw-Yang Hwang
- Department of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-4951, USA
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22
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Fiorentini D, Hakim G, Bonsi L, Bagnara GP, Maraldi T, Landi L. Acute regulation of glucose transport in a human megakaryocytic cell line: difference between growth factors and H(2)O(2). Free Radic Biol Med 2001; 31:923-31. [PMID: 11585711 DOI: 10.1016/s0891-5849(01)00678-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The present study was undertaken to: (i) compare the effect of some hematopoietic growth factors, like interleukine-3, thrombopoietin, granulocyte-megakaryocyte colony-stimulating factor, stem cell factor, and reactive oxygen species such as H(2)O(2) on glucose uptake in a human leukemic megakaryocytic cell line, M07; (ii) investigate the changes in kinetic parameters of the transport activity induced by these stimuli; and (iii) evaluate the effect of genistein, a tyrosine kinase inhibitor, on the glucose uptake activation by the cited agents. The results are as follows: (i) exposure of M07 cells to thrombopoietin, granulocyte-megakaryocyte colony-stimulating factor, and stem cell factor resulted in a rapid stimulation of glucose transport; interleukine-3-treated cells exhibited no increase in the rate of glucose uptake, although M07 proliferation is interleukine-3 dependent; a rapid glucose transport enhancement was also observed when M07 cells were exposed to low doses of H(2)O(2); (ii) the transport kinetic parameters point out that an important difference exists between the effect of cytokines and that of H(2)O(2): cytokines increased predominantly the affinity for glucose, while H(2)O(2) raised both the V(max) and K(m) values; (iii) the isoflavone genistein, at a very low concentration, inhibited the stem cell factor- or H(2)O(2)-induced stimulation of hexose transport, reversing the variations of K(m) and V(max), but it did not affect the transport activity of granulocyte-megakaryocyte colony-stimulating factor-treated cells; and (iv) catalase completely abolished the stimulatory action of H(2)O(2) on glucose transport and slightly prevented the effect of stem cell factor, while caffeic acid phenethyl ester was only able to affect the activation due to stem cell factor.
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Affiliation(s)
- D Fiorentini
- Dipartimento di Biochimica G. Moruzzi, Università di Bologna, Via Irnerio, 48, I-40126 Bologna, Italy
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23
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Favilli F, Catarzi S, Iantomasi T, Vincenzini MT. Glutathione transport system in NIH3t3 fibroblasts. MOLECULAR CELL BIOLOGY RESEARCH COMMUNICATIONS : MCBRC 2000; 4:212-8. [PMID: 11409914 DOI: 10.1006/mcbr.2001.0280] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The current study characterizes a mediated transport for GSH uptake in murine fibroblasts NIH3T3. The presence of GSH mediated transport is indicated by the behaviour of GSH uptake time-course, as well as by kinetic saturation and the specific inhibition of the initial rate of GSH transport. Moreover, a concentrative GSH uptake has been measured, whose driving force may be due to a change of membrane potential and the direct involvement of ATP. Hyperbolic kinetic saturation shows a single mediated transport with high affinity for GSH (Km = 0.209 +/- 0.03 mM). High specificity of this GSH transporter for the entire structure of GSH is also demonstrated. To summarize, GSH uptake into NIH3T3 cells occurs by an active transport system and shows characteristics similar to ATP-dependent mechanisms previously identified in hepatocyte membranes. Moreover, a possible physiological role of this GSH transporter related to NIH3T3 cell proliferation has been hypothesized.
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Affiliation(s)
- F Favilli
- Department of Biochemical Sciences, University of Firenze, viale Morgagni 50, Florence, 50134, Italy
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24
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Abbud W, Habinowski S, Zhang JZ, Kendrew J, Elkairi FS, Kemp BE, Witters LA, Ismail-Beigi F. Stimulation of AMP-activated protein kinase (AMPK) is associated with enhancement of Glut1-mediated glucose transport. Arch Biochem Biophys 2000; 380:347-52. [PMID: 10933890 DOI: 10.1006/abbi.2000.1935] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In cells expressing only the Glut1 isoform of glucose transporters, we have shown that glucose transport is markedly stimulated in response to hypoxia or inhibition of oxidative phosphorylation, conditions that would be expected to cause a stimulation of AMP-activated protein kinase (AMPK) activity. In the present study we tested the hypothesis that the stimulation of AMPK activity might be accompanied by an enhancement of Glut1-mediated glucose transport. Exposure of Clone 9 cells, 3T3-L1 preadipocytes, and C(2)C(12) myoblasts (cells that express only the Glut1 isoform) to 5-aminoimidazole-4-carboxamideribonucleoside (AICAR), an adenosine analog that stimulates AMPK activity, resulted in a marked increase in the rate of glucose transport (ranging from four- to sixfold) that was accompanied by activation of AMPK. This stimulation of AMPK activity was associated with an increase in the phosphorylation of threonine 172 on the activation loop of its alpha subunit, with the predominant change being in the alpha-2 isoform. Exposure of Clone 9 cells to 5-iodotubercidin, an inhibitor of adenosine kinase, abolished the accumulation of AICAR-5'-monophosphate (ZMP), stimulation of AMPK, and the enhancement of glucose transport in response to AICAR. There was no significant increase in the content of Glut1 in plasma membranes of Clone 9 cells exposed to AICAR. We conclude that stimulation of AMPK activity is associated with enhancement of Glut1-mediated glucose transport, and that the glucose transport response is mediated by activation of Glut1 transporters preexisting in the plasma membrane.
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Affiliation(s)
- W Abbud
- Departments of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-4951, USA
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Hamrahian AH, Zhang JZ, Elkhairi FS, Prasad R, Ismail-Beigi F. Activation of Glut1 glucose transporter in response to inhibition of oxidative phosphorylation. Arch Biochem Biophys 1999; 368:375-9. [PMID: 10441390 DOI: 10.1006/abbi.1999.1320] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have previously shown that exposure of Clone 9 cells to hypoxia, cyanide, or azide results in an acute stimulation of glucose transport that is largely mediated by "activation" of glucose transporter (Glut1) sites preexisting in the plasma membrane. However, it is not known whether inhibition of oxidative phosphorylation only at its terminal step, or at any of its steps, leads to the glucose transport response. Hence, the effect of azide (5 mM), rotenone (1 microM), rotenone (1 microM) plus thenoyltrifluoroacetone (TTFA) (5 microM), antimycin A (0.3 microM), dinitrophenol (0.25 mM), carbonyl cyanide m-chlorophenylhydrazone (CCCP) (2.5 microM), and oligomycin B (0.15 microM) on glucose transport was determined. All of the above agents elicited a similar approximately 4-fold stimulation of cytochalasin B (CB)-inhibitable 3-O-methyl glucose (3-OMG) uptake in Clone 9 cells. The stimulatory effect of azide on 3-OMG uptake was not inhibited by antioxidants 2-mercaptopropionyl glycine (1.2 mM) and 1,10-phenanthroline (40 microM), while, in contrast, the antioxidants attenuated the stimulation of glucose transport in response to 250 microM H(2)O(2) by approximately 50%. To differentiate between an increase in the number of functional Glut1 sites in the plasma membrane (in the absence of "translocation") versus an increase in the "intrinsic activity" of Glut1, the effect of azide on the energy of activation (E(a)) of glucose transport was measured. The E(a) was determined by measuring the rate of CB-inhibitable 3-OMG uptake at 24.0, 28.0, 35. 0, and 40 degrees C. The E(a) of control Clone 9 cells and of cells exposed to 10 mM azide for 2 h was 32,530 +/- 1830 and 31,220 +/- 600 J/mol, respectively (P > 0.1), while the rate of CB-inhibitable 3-OMG uptake was 9.3 +/- 0.7-fold higher in azide-treated cells. It is concluded that (i) inhibition of oxidative phosphorylation, at any of its steps, leads to a stimulation of glucose transport, and (ii) the mechanism of stimulation of glucose transport in response to azide appears to be predominately mediated by an apparent increase in the number of functional Glut1 sites in the plasma membrane (instead of an increase in their "intrinsic activity"), suggesting an "unmasking" mechanism.
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Affiliation(s)
- A H Hamrahian
- Departments of Medicine and of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio, 44106-4951, USA
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