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Zhou J, Shi Y, Yang C, Lu S, Zhao L, Liu X, Zhou D, Luo L, Yin Z. γ-glutamylcysteine alleviates insulin resistance and hepatic steatosis by regulating adenylate cyclase and IGF-1R/IRS1/PI3K/Akt signaling pathways. J Nutr Biochem 2023:109404. [PMID: 37311491 DOI: 10.1016/j.jnutbio.2023.109404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 06/02/2023] [Accepted: 06/07/2023] [Indexed: 06/15/2023]
Abstract
Type 2 diabetes mellitus (T2DM), a complex metabolism disease, which was characterized by metabolic disorders including hyperglycemia, has become a major health problem due to the increasing prevalence worldwide. γ-glutamylcysteine (γ-GC) as an immediate precursor of glutathione (GSH) was originally used for the treatment of sepsis, inflammation bowel disease, and senescence. Here, we evaluated the capacity of γ-GC on diabetes-related metabolic parameters in db/db mice and insulin resistance (IR) amelioration in cells induced by palmitic acid (PA). Our data suggested that γ-GC treatment decreased body weight, reduced adipose tissue size, ameliorated ectopic fat deposition in liver, increased the GSH content in liver, improved glucose control and other diabetes-related metabolic parameters in vivo. Moreover, in vitro experiments showed that γ-GC could maintain the balance of free fatty acids (FFAs) and glucose uptake through regulating the translocation of CD36 and GLUT4 from cytoplasm to plasma membrane. Furthermore, our finding also provided evidence that γ-GC could activate Akt not only via adenylate cyclase (AC)/cAMP/PI3K signaling pathway, but also via IGF-1R/IRS1/PI3K signaling pathway to improve IR and hepatic steatosis. Blocking either of two signaling pathways could not activate Akt activation induced by γ-GC. This unique characteristic ensures the important role of γ-GC in glucose metabolism. Collectively, these results suggested that γ-GC could serve as a candidate dipeptide for the treatment of T2DM and related chronic diabetic complications via activating AC and IGF-1R/IRS1/PI3K/Akt signaling pathways to regulate CD36 and GLUT4 trafficking.
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Affiliation(s)
- Jinyi Zhou
- Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing, China
| | - Yingying Shi
- Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing, China
| | - Chen Yang
- Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing, China
| | - Shuai Lu
- Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing, China
| | - Lishuang Zhao
- Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing, China
| | - Xianli Liu
- Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing, China
| | - Da Zhou
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, Shanghai, People's Republic of China.
| | - Lan Luo
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China.
| | - Zhimin Yin
- Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing, China.
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MacKrell JG, Cartee GD. A novel method to measure glucose uptake and myosin heavy chain isoform expression of single fibers from rat skeletal muscle. Diabetes 2012; 61:995-1003. [PMID: 22396201 PMCID: PMC3331778 DOI: 10.2337/db11-1299] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Skeletal muscle includes many individual fibers with diverse phenotypes. A barrier to understanding muscle glucose uptake at the cellular level has been the absence of a method to measure glucose uptake by single fibers from mammalian skeletal muscle. This study's primary objective was to develop a procedure to measure glucose uptake by single fibers from rat skeletal muscle. Rat epitrochlearis muscles were incubated ex vivo with [(3)H]-2-deoxy-d-glucose, with or without insulin or AICAR, before isolation of ~10-30 single fibers from each muscle. Fiber type (myosin heavy chain [MHC] isoform) and glucose uptake were determined for each single fiber. Insulin-stimulated glucose uptake (which was cytochalasin B inhibitable) varied according to MHC isoform expression, with ~2-fold greater values for IIA versus IIB or IIX fibers and ~1.3-fold greater for hybrid (IIB/X) versus IIB fibers. In contrast, AICAR-stimulated glucose uptake was ~1.5-fold greater for IIB versus IIA fibers. A secondary objective was to assess insulin resistance of single fibers from obese versus lean Zucker rats. Genotype differences were observed for insulin-stimulated glucose uptake and inhibitor κB (IκB)-β abundance in single fibers (obese less than lean), with decrements for glucose uptake (44-58%) and IκB-β (25-32%) in each fiber type. This novel method creates a unique opportunity for future research focused on understanding muscle glucose uptake at the cellular level.
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Affiliation(s)
- James G. MacKrell
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Gregory D. Cartee
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
- Institute of Gerontology, University of Michigan, Ann Arbor, Michigan
- Corresponding author: Gregory D. Cartee,
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3
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Post-exercise carbohydrate plus whey protein hydrolysates supplementation increases skeletal muscle glycogen level in rats. Amino Acids 2009; 38:1109-15. [DOI: 10.1007/s00726-009-0321-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2009] [Accepted: 06/25/2009] [Indexed: 10/20/2022]
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Natalicchio A, De Stefano F, Perrini S, Laviola L, Cignarelli A, Caccioppoli C, Quagliara A, Melchiorre M, Leonardini A, Conserva A, Giorgino F. Involvement of the p66Shc protein in glucose transport regulation in skeletal muscle myoblasts. Am J Physiol Endocrinol Metab 2009; 296:E228-37. [PMID: 18957618 DOI: 10.1152/ajpendo.90347.2008] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The p66(Shc) protein isoform regulates MAP kinase activity and the actin cytoskeleton turnover, which are both required for normal glucose transport responses. To investigate the role of p66(Shc) in glucose transport regulation in skeletal muscle cells, L6 myoblasts with antisense-mediated reduction (L6/p66(Shc)as) or adenovirus-mediated overexpression (L6/p66(Shc)adv) of the p66(Shc) protein were examined. L6/(Shc)as myoblasts showed constitutive activation of ERK-1/2 and disruption of the actin network, associated with an 11-fold increase in basal glucose transport. GLUT1 and GLUT3 transporter proteins were sevenfold and fourfold more abundant, respectively, and were localized throughout the cytoplasm. Conversely, in L6 myoblasts overexpressing p66(Shc), basal glucose uptake rates were reduced by 30% in parallel with a approximately 50% reduction in total GLUT1 and GLUT3 transporter levels. Inhibition of the increased ERK-1/2 activity with PD98059 in L6/(Shc)as cells had a minimal effect on increased GLUT1 and GLUT3 protein levels, but restored the actin cytoskeleton, and reduced the abnormally high basal glucose uptake by 70%. In conclusion, p66(Shc) appears to regulate the glucose transport system in skeletal muscle myoblasts by controlling, via MAP kinase, the integrity of the actin cytoskeleton and by modulating cellular expression of GLUT1 and GLUT3 transporter proteins via ERK-independent pathways.
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Affiliation(s)
- Annalisa Natalicchio
- Dept. of Emergency and Organ Transplantation, Section on Internal Medicine, Endocrinology and Metabolic Diseases, Univ. of Bari, Piazza Giulio Cesare, 11, I-70124 Bari, Italy
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5
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Kevorkova O, Ethier-Chiasson M, Lafond J. Differential Expression of Glucose Transporters in Rabbit Placenta: Effect of Hypercholesterolemia in Dams1. Biol Reprod 2007; 76:487-95. [PMID: 17135483 DOI: 10.1095/biolreprod.106.055285] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Low birth weight is observed in rabbit offspring when maternal hypercholesterolemia is induced during gestation, but the related etiology is still unknown. Glucose is one of the most important substances during fetal development, and defect in glucose supply to fetus was related to pathophysiological mechanisms in intrauterine growth restriction. Thus, the aim of this work was to evaluate the impact of maternal hypercholesterolemia during rabbit gestation on the glucose metabolism and the routing of glucose transporters (SLC2 and SLC5 [previously known as GLUT and SGLT]) in placenta. In this study, maternal and offspring serum levels of glucose and insulin were evaluated for control and hypercholesterolemic groups, and the mRNA and protein expressions of placental SLCs were quantified by real-time RT-PCR and Western immunoblot, respectively. Our data demonstrate that maternal hypercholesterolemia during gestation: 1) induces offspring hypoglycemia; 2) does not modify the genetic and protein expressions of SLC2A1 and SLC2A4 (previously GLUT1 and GLUT4) in total placental extract; 3) downregulates the placental SLC5A1 (previously SGLT1) protein expression without affecting its mRNA levels; 4) impairs the translocation of SLC2A1 but not SLC2A4 from cytoplasmatic pool to the cell membrane surface. Then we assume that reduction of offspring birth weight in presence of maternal hypercholesterolemia may be related to the offspring's hypoglycemia and the reduction of the cell surface expression of placental SLC2A1.
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Affiliation(s)
- Olha Kevorkova
- Laboratoire de Physiologie Materno-Foetale, and Centre de Recherche BioMed, Université du Québec à Montréal, Montréal, Québec, Canada H3C 3P8
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6
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Maraldi T, Fiorentini D, Prata C, Landi L, Hakim G. Glucose-transport regulation in leukemic cells: how can H2O2 mimic stem cell factor effects? Antioxid Redox Signal 2007; 9:271-9. [PMID: 17115933 DOI: 10.1089/ars.2007.9.271] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In leukemic cells, glucose transport is activated by SCF and H2O2 through a common signal cascade involving Akt, PLCgamma, Syk, and the Src family, in this order. An explanation can be provided by the phosphorylation of c-kit, the SCF receptor, elicited by either SCF or H2O2. Moreover, antioxidants prevent the SCF effect on glucose transport, confirming the involvement of H2O2 in the pathway leading to glucose-transport activation and suggesting a potential role for reactive oxygen species in leukemia proliferation.
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Affiliation(s)
- Tullia Maraldi
- Department of Biochemistry "G. Moruzzi," University of Bologna, Italy.
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7
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Liu LZ, He AB, Liu XJ, Li Y, Chang YS, Fang FD. Protein kinase Czeta and glucose uptake. BIOCHEMISTRY (MOSCOW) 2006; 71:701-6. [PMID: 16903823 DOI: 10.1134/s0006297906070017] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Protein kinase Czeta (PKCzeta) is a member of the PKC family, serving downstream of insulin receptor and phosphatidylinositol (PI) 3-kinase. Many evidences suggest that PKCzeta plays a very important role in activating glucose transport response. Not only insulin but also glucose and exercise can activate PKCzeta through diverse pathways. PKCzeta activation and activity are impaired with insulin resistance in muscle and adipose tissues of type II diabetes individuals, but heightened in liver tissue, wherein it also increases lipid synthesis mediated by SREBP-1c (sterol-regulatory element-binding protein). Many studies have focused on linkage between PKCzeta and GLUT4 translocation and activation. Exploring the molecular mechanisms and pathways by which PKCzeta mediates glucose transport will highlight the insulin-signaling pathway.
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Affiliation(s)
- Li-Zhong Liu
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China
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8
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Liu LZ, Zhao HL, Zuo J, Ho SKS, Chan JCN, Meng Y, Fang FD, Tong PCY. Protein kinase Czeta mediates insulin-induced glucose transport through actin remodeling in L6 muscle cells. Mol Biol Cell 2006; 17:2322-30. [PMID: 16525020 PMCID: PMC1446104 DOI: 10.1091/mbc.e05-10-0969] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Protein kinase C (PKC) zeta has been implicated in insulin-induced glucose uptake in skeletal muscle cell, although the underlying mechanism remains unknown. In this study, we investigated the effect of PKCzeta on actin remodeling and glucose transport in differentiated rat L6 muscle cells expressing myc-tagged glucose transporter 4 (GLUT4). On insulin stimulation, PKCzeta translocated from low-density microsomes to plasma membrane accompanied by increase in GLUT4 translocation and glucose uptake. Z-scan confocal microscopy revealed a spatial colocalization of relocated PKCzeta with the small GTPase Rac-1, actin, and GLUT4 after insulin stimulation. The insulin-mediated colocalization, PKCzeta distribution, GLUT4 translocation, and glucose uptake were inhibited by wortmannin and cell-permeable PKCzeta pseudosubstrate peptide. In stable transfected cells, overexpression of PKCzeta caused an insulin-like effect on actin remodeling accompanied by a 2.1-fold increase in GLUT4 translocation and 1.7-fold increase in glucose uptake in the absence of insulin. The effects of PKCzeta overexpression were abolished by cell-permeable PKCzeta pseudosubstrate peptide, but not wortmannin. Transient transfection of constitutively active Rac-1 recruited PKCzeta to new structures resembling actin remodeling, whereas dominant negative Rac-1 prevented the insulin-mediated PKCzeta translocation. Together, these results suggest that PKCzeta mediates insulin effect on glucose transport through actin remodeling in muscle cells.
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Affiliation(s)
- Li-Zhong Liu
- Department of Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, 100005 Beijing, China
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10
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Klip A, Marette A. Regulation of Glucose Transporters by Insulin and Exercise: Cellular Effects and Implications for Diabetes. Compr Physiol 2001. [DOI: 10.1002/cphy.cp070214] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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11
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Braiman L, Alt A, Kuroki T, Ohba M, Bak A, Tennenbaum T, Sampson SR. Activation of protein kinase C zeta induces serine phosphorylation of VAMP2 in the GLUT4 compartment and increases glucose transport in skeletal muscle. Mol Cell Biol 2001; 21:7852-61. [PMID: 11604519 PMCID: PMC99955 DOI: 10.1128/mcb.21.22.7852-7861.2001] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Insulin stimulates glucose uptake into skeletal muscle tissue mainly through the translocation of glucose transporter 4 (GLUT4) to the plasma membrane. The precise mechanism involved in this process is presently unknown. In the cascade of events leading to insulin-induced glucose transport, insulin activates specific protein kinase C (PKC) isoforms. In this study we investigated the roles of PKC zeta in insulin-stimulated glucose uptake and GLUT4 translocation in primary cultures of rat skeletal muscle. We found that insulin initially caused PKC zeta to associate specifically with the GLUT4 compartments and that PKC zeta together with the GLUT4 compartments were then translocated to the plasma membrane as a complex. PKC zeta and GLUT4 recycled independently of one another. To further establish the importance of PKC zeta in glucose transport, we used adenovirus constructs containing wild-type or kinase-inactive, dominant-negative PKC zeta (DNPKC zeta) cDNA to overexpress this isoform in skeletal muscle myotube cultures. We found that overexpression of PKC zeta was associated with a marked increase in the activity of this isoform. The overexpressed, active PKC zeta coprecipitated with the GLUT4 compartments. Moreover, overexpression of PKC zeta caused GLUT4 translocation to the plasma membrane and increased glucose uptake in the absence of insulin. Finally, either insulin or overexpression of PKC zeta induced serine phosphorylation of the GLUT4-compartment-associated vesicle-associated membrane protein 2. Furthermore, DNPKC zeta disrupted the GLUT4 compartment integrity and abrogated insulin-induced GLUT4 translocation and glucose uptake. These results demonstrate that PKC zeta regulates insulin-stimulated GLUT4 translocation and glucose transport through the unique colocalization of this isoform with the GLUT4 compartments.
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Affiliation(s)
- L Braiman
- Faculty of Life Sciences, Gonda-Goldschmied Center, Bar-Ilan University, Ramat-Gan 52900, Israel
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12
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Shen S, Wertheimer E, Sampson SR, Tennenbaum T. Characterization of glucose transport system in keratinocytes: insulin and IGF-1 differentially affect specific transporters. J Invest Dermatol 2000; 115:949-54. [PMID: 11121124 DOI: 10.1046/j.1523-1747.2000.00161.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Skin is one of the major tissues displaying chronic diabetic complications. We have studied glucose transport following stimulation with insulin and IGF-1 in cultured mouse keratinocytes. In proliferating cells, acute stimulation with insulin and IGF-1 increased glucose uptake. Insulin translocated glucose transporters 1 and 5, whereas IGF-1 translocated glucose transporters 2 and 3. With differentiation, glucose transporter 3 expression increased and the expression of glucose transporters 1, 2, and 5 decreased. No increase in glucose uptake was observed, however, following stimulation with either hormone. These results indicate that insulin and IGF-1 differentially regulate glucose uptake as well as expression and translocation of specific transporters in skin keratinocytes.
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Affiliation(s)
- S Shen
- Faculty of Life Sciences, Gonda-Goldschmeid Center, Bar-Ilan University, Ramat-Gan, Israel
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13
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Khayat ZA, McCall AL, Klip A. Unique mechanism of GLUT3 glucose transporter regulation by prolonged energy demand: increased protein half-life. Biochem J 1998; 333 ( Pt 3):713-8. [PMID: 9677332 PMCID: PMC1219636 DOI: 10.1042/bj3330713] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
L6 muscle cells survive long-term (18 h) disruption of oxidative phosphorylation by the mitochondrial uncoupler 2,4-dinitrophenol (DNP) because, in response to this metabolic stress, they increase their rate of glucose transport. This response is associated with an elevation of the protein content of glucose transporter isoforms GLUT3 and GLUT1, but not GLUT4. Previously we have reported that the rise in GLUT1 expression is likely to be a result of de novo biosynthesis of the transporter, since the uncoupler increases GLUT1 mRNA levels. Unlike GLUT1, very little is known about how interfering with mitochondrial ATP production regulates GLUT3 protein expression. Here we examine the mechanisms employed by DNP to increase GLUT3 protein content and glucose uptake in L6 muscle cells. We report that, in contrast with GLUT1, continuous exposure to DNP had no effect on GLUT3 mRNA levels. DNP-stimulated glucose transport was unaffected by the protein-synthesis inhibitor cycloheximide. The increase in GLUT3 protein mediated by DNP was also insensitive to cycloheximide, paralleling the response of glucose uptake, whereas the rise in GLUT1 protein levels was blocked by the inhibitor. The GLUT3 glucose transporter may therefore provide the majority of the glucose transport stimulation by DNP, despite elevated levels of GLUT1 protein. The half-lives of GLUT3 and GLUT1 proteins in L6 myotubes were determined to be about 15 h and 6 h respectively. DNP prolonged the half-life of both proteins. After 24 h of DNP treatment, 88% of GLUT3 protein and 57% of GLUT1 protein had not turned over, compared with 25% in untreated cells. We conclude that the long-term stimulation of glucose transport by DNP arises from an elevation of GLUT3 protein content associated with an increase in GLUT3 protein half-life. These findings suggest that disruption of the oxidative chain of L6 muscle cells leads to an adaptive response of glucose transport that is distinct from the insulin response, involving specific glucose transporter isoforms that are regulated by different mechanisms.
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Affiliation(s)
- Z A Khayat
- Programme in Cell Biology, The Hospital for Sick Children, 555 University Ave., Toronto, Ontario, Canada, M5G 1X8, and Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada, M5S 1A8
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Broydell M, Mazzuca DM, Kudo PA, Lo TC. The role of the GLUT 4 transporter in regulating rat myoblast glucose transport processes. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1371:295-308. [PMID: 9630683 DOI: 10.1016/s0005-2736(98)00027-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Previous studies revealed an inverse relationship between GLUT 1 and GLUT 4 expression in rat myoblasts [L. Xia, Z. Lu, T.C.Y. Lo, J. Biol. Chem., 268 (1993) 23258-23266]. It was not clear whether these were coincidental or causal occurrences. To examine the regulatory roles of the GLUT 4 isoform, rat L6 myoblasts were transfected with full length GLUT 4 cDNAs (2.5 kb) in the sense or antisense orientation. L6 myoblasts transfected with the GLUT 4 sense cDNA (L6/G4S transfectants) possessed much elevated levels of both endogenous GLUT 4 transcripts (1.4 kb and 2.8 kb). Transport and immunofluorescence studies showed that this GLUT 4 sense cDNA was responsible for a functional GLUT 4 transporter. L6 cells transfected with the GLUT 4 antisense cDNA (L6/G4A transfectants) possessed only 6% of the L6 level in day 6 cultures. These antisense transfectants were essentially devoid of any functional GLUT 4 transporter. The activation of transcription of the endogenous GLUT 4 gene in L6/G4S myoblasts suggested auto-regulation of GLUT 4 expression. GLUT 3 expression and activity were not altered in both sense and antisense GLUT 4 transfectants. More interestingly, GLUT 1 expression was reduced in L6/G4S myoblasts, whereas it was elevated in L6/G4A myoblasts. This was the first direct evidence indicating GLUT 4 might play an important role in suppressing GLUT 1 expression.
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Affiliation(s)
- M Broydell
- Department of Biochemistry, University of Western Ontario, London, Ontario, Canada
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15
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Bortoff KD, Zhu CC, Hrywna Y, Messina JL. Insulin induction of pip 92, CL-6, and novel mRNAs in rat hepatoma cells. Endocrine 1997; 7:199-207. [PMID: 9549046 DOI: 10.1007/bf02778142] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Insulin directly affects many aspects of cellular metabolism. An additional, poorly studied effect of insulin is the regulation of multiple genes whose products are important in many cellular functions. Using differential screening techniques, we identified insulin-regulated genes induced in insulin-treated rat H4IIE (H4) hepatoma cells. Two of the mRNAs identified were homologous to the previously characterized mouse pip 92 and rat CL-6 immediate-early genes. The pip 92 clone was initially isolated from mitogen-stimulated mouse Balb/c 3T3 fibroblasts, whereas the CL-6 clone was first isolated from regenerating rat liver. In this article, we demonstrated that in rat H4 cells, the transcription rates of both pip 92 and CL-6 are induced by insulin alone. Additionally, we showed that the transcription rates of two other genes, whose sequences are not homologous to any other sequences in gene bank ("novel genes"), were rapidly and transiently induced by insulin. These results demonstrate that insulin regulates the expression of several novel genes with a time-course similar to members of the immediate-early response gene family.
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Affiliation(s)
- K D Bortoff
- Department of Physiology, SUNY Health Science Center, Syracuse, NY, USA
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16
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Luiken JJ, van Nieuwenhoven FA, America G, van der Vusse GJ, Glatz JF. Uptake and metabolism of palmitate by isolated cardiac myocytes from adult rats: involvement of sarcolemmal proteins. J Lipid Res 1997. [DOI: 10.1016/s0022-2275(20)37241-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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17
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Ranganathan S, Davidson MB. Effect of tumor necrosis factor-alpha on basal and insulin-stimulated glucose transport in cultured muscle and fat cells. Metabolism 1996; 45:1089-94. [PMID: 8781295 DOI: 10.1016/s0026-0495(96)90007-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
It has been reported that tumor necrosis factor-alpha (TNF-alpha) inhibits insulin action in adipocytes and plays an important role as mediator of insulin resistance in non-insulin-dependent diabetes. The effect of this cytokine on insulin action in muscle, which is responsible for 80% of the glucose disposal in the body, has not been studied. Therefore, we examined the effect of TNF-alpha on basal and insulin-mediated transport of 2-deoxy[3H]-glucose in L6 rat muscle cells. TNF-alpha treatment for 5 days up to a concentration of 20 ng/mL or 8 days at 10 ng/mL did not inhibit the insulin-stimulated increase in deoxyglucose transport in L6 cells. However, there was a significant increase in basal transport in TNF-alpha- treated cells. Comparative experiments with 3T3-L1 adipocytes showed that in cells cultured with insulin, TNF-alpha decreased basal transport but the insulin-stimulated increase was unaffected. In cells cultured without insulin, basal transport was slightly increased and the insulin-stimulated increase in transport was decreased by approximately 60% but the cell protein was decreased by approximately 60%, suggesting cytotoxicity. Cells cultured without insulin were more sensitive to inhibition of 14C-alanine incorporation into proteins by low concentrations of TNF-alpha compared with cells cultured with insulin. These results suggest that TNF-alpha affects glucose metabolism, causing increased basal uptake in muscle cells and decreased uptake in adipocytes. TNF-alpha appears to affect general cell metabolism, including glucose transport in adipocytes, and not specifically insulin-stimulated glucose transport.
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Affiliation(s)
- S Ranganathan
- Research Institute, Cedars-Sinai Medical Center-UCLA, Los Angeles, CA, USA
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18
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Wagstaff P, Kang HY, Mylott D, Robbins PJ, White MK. Characterization of the avian GLUT1 glucose transporter: differential regulation of GLUT1 and GLUT3 in chicken embryo fibroblasts. Mol Biol Cell 1995; 6:1575-89. [PMID: 8589457 PMCID: PMC301312 DOI: 10.1091/mbc.6.11.1575] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Vertebrate cells that are transformed by oncogenes such as v-src or are stimulated by mitogens have increased rates of glucose uptake. In rodent cells, the mechanisms whereby glucose transport is up-regulated are well understood. Stimulation of glucose transport involves an elevation in mRNA encoding the GLUT1 glucose transporter that is controlled at the levels of both transcription and mRNA stability. Cloning and sequencing of chicken GLUT1 cDNA showed that it shares 95% amino acid sequence similarity to mammalian GLUT1s. Nevertheless, unlike mammalian GLUT1 mRNA, it was not induced by v-src, serum addition, or treatment with the tumor promoter 12-O-tetradecanoylphorbol 13-acetate in chicken embryo fibroblasts. Rather, the induction of glucose transport in chicken embryo fibroblasts by v-src, serum, and 12-O-tetradecanoylphorbol 13-acetate was associated with induction of GLUT3 mRNA level and GLUT3 transcription. Rat fibroblasts were also found to express both GLUT1 and GLUT3 isoforms, but v-src induced GLUT1 and not GLUT3. This suggests that animal cells require both a basal and an upregulatable glucose transporter and that these functions have been subsumed by different GLUT isoforms in avian and mammalian cells.
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Affiliation(s)
- P Wagstaff
- Department of Microbiology and Immunology, East Carolina University School of Medicine, Greenville, North Carolina 27858, USA
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Taha C, Mitsumoto Y, Liu Z, Skolnik EY, Klip A. The insulin-dependent biosynthesis of GLUT1 and GLUT3 glucose transporters in L6 muscle cells is mediated by distinct pathways. Roles of p21ras and pp70 S6 kinase. J Biol Chem 1995; 270:24678-81. [PMID: 7559581 DOI: 10.1074/jbc.270.42.24678] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Insulin binding results in rapid phosphorylation of insulin receptor substrate-1 to activate p21ras and mitogen-activated protein kinase. Insulin also activates the ribosomal protein S6 kinase (pp70 S6 kinase) independently of the Ras pathway. Chronic (18 h) treatment of L6 muscle cells with insulin increases glucose transport activity severalfold due to biosynthetic elevation of the GLUT1 and GLUT3 but not the GLUT4 glucose transporters. Here we investigate the roles of p21ras and pp70 S6 kinase in the insulin-mediated increases in GLUT1 and GLUT3 expression. L6 cells were transfected with the dominant negative Ras(S17N) under the control of a dexamethasone-inducible promoter. Induction of Ras(S17N) failed to block the insulin-mediated increase in GLUT1 glucose transporter protein and mRNA; however, it abrogated the insulin-mediated increase in GLUT3 glucose transporter protein and mRNA. Inhibition of pp70 S6 kinase by rapamycin, on the other hand, eliminated the insulin-mediated increase in GLUT1 but had no effect on that of GLUT3 in both parental and Ras(S17N) transfected L6 cells. These results suggest that the biosynthetic regulation of glucose transporters is differentially determined, with pp70 S6 kinase and p21ras playing active roles in the insulin-stimulated increases in GLUT1 and GLUT3, respectively.
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Affiliation(s)
- C Taha
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
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Tsakiridis T, Vranic M, Klip A. Phosphatidylinositol 3-kinase and the actin network are not required for the stimulation of glucose transport caused by mitochondrial uncoupling: comparison with insulin action. Biochem J 1995; 309 ( Pt 1):1-5. [PMID: 7619042 PMCID: PMC1135791 DOI: 10.1042/bj3090001] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In L6 myotubes insulin stimulates glucose transport through the translocation of glucose transporters GLUT1, GLUT3 and GLUT4 from intracellular stores to the plasma membrane. An intact actin network and phosphatidylinositol 3-kinase activity are required for this process. Glucose transport is also stimulated by the mitochondrial ATP-production uncoupler dinitrophenol. We show here that, in serum-depleted myotubes, dinitrophenol induced translocation of GLUT1 and GLUT4, but not GLUT3. This response was not affected by inhibiting phosphatidylinositol 3-kinase or disassembling the actin network. Insulin, but not dinitrophenol, caused tyrosine phosphorylation of several polypeptides, including the insulin-receptor substrate-1 and mitogen-activated protein kinase. Similarly, insulin, but not dinitrophenol, caused actin reorganization, which was inhibited by wortmannin. We conclude that insulin and dinitrophenol stimulate glucose transport by different mechanisms.
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Affiliation(s)
- T Tsakiridis
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
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Disassembly of the actin network inhibits insulin-dependent stimulation of glucose transport and prevents recruitment of glucose transporters to the plasma membrane. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(18)43971-3] [Citation(s) in RCA: 145] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Bolander FF. Phosphorylation and Other Nontranscriptional Effects of Hormones. Mol Endocrinol 1994. [DOI: 10.1016/b978-0-12-111231-8.50016-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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