1
|
Packer M. Fetal Reprogramming of Nutrient Surplus Signaling, O-GlcNAcylation, and the Evolution of CKD. J Am Soc Nephrol 2023; 34:1480-1491. [PMID: 37340541 PMCID: PMC10482065 DOI: 10.1681/asn.0000000000000177] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Accepted: 06/07/2023] [Indexed: 06/22/2023] Open
Abstract
ABSTRACT Fetal kidney development is characterized by increased uptake of glucose, ATP production by glycolysis, and upregulation of mammalian target of rapamycin (mTOR) and hypoxia-inducible factor-1 alpha (HIF-1 α ), which (acting in concert) promote nephrogenesis in a hypoxic low-tubular-workload environment. By contrast, the healthy adult kidney is characterized by upregulation of sirtuin-1 and adenosine monophosphate-activated protein kinase, which enhances ATP production through fatty acid oxidation to fulfill the needs of a normoxic high-tubular-workload environment. During stress or injury, the kidney reverts to a fetal signaling program, which is adaptive in the short term, but is deleterious if sustained for prolonged periods when both oxygen tension and tubular workload are heightened. Prolonged increases in glucose uptake in glomerular and proximal tubular cells lead to enhanced flux through the hexosamine biosynthesis pathway; its end product-uridine diphosphate N -acetylglucosamine-drives the rapid and reversible O-GlcNAcylation of thousands of intracellular proteins, typically those that are not membrane-bound or secreted. Both O-GlcNAcylation and phosphorylation act at serine/threonine residues, but whereas phosphorylation is regulated by hundreds of specific kinases and phosphatases, O-GlcNAcylation is regulated only by O-GlcNAc transferase and O-GlcNAcase, which adds or removes N-acetylglucosamine, respectively, from target proteins. Diabetic and nondiabetic CKD is characterized by fetal reprogramming (with upregulation of mTOR and HIF-1 α ) and increased O-GlcNAcylation, both experimentally and clinically. Augmentation of O-GlcNAcylation in the adult kidney enhances oxidative stress, cell cycle entry, apoptosis, and activation of proinflammatory and profibrotic pathways, and it inhibits megalin-mediated albumin endocytosis in glomerular mesangial and proximal tubular cells-effects that can be aggravated and attenuated by augmentation and muting of O-GlcNAcylation, respectively. In addition, drugs with known nephroprotective effects-angiotensin receptor blockers, mineralocorticoid receptor antagonists, and sodium-glucose cotransporter 2 inhibitors-are accompanied by diminished O-GlcNAcylation in the kidney, although the role of such suppression in mediating their benefits has not been explored. The available evidence supports further work on the role of uridine diphosphate N -acetylglucosamine as a critical nutrient surplus sensor (acting in concert with upregulated mTOR and HIF-1 α signaling) in the development of diabetic and nondiabetic CKD.
Collapse
Affiliation(s)
- Milton Packer
- Baylor Heart and Vascular Institute , Dallas , Texas and Imperial College , London , United Kingdom
| |
Collapse
|
2
|
Packer M. Foetal recapitulation of nutrient surplus signalling by O-GlcNAcylation and the failing heart. Eur J Heart Fail 2023; 25:1199-1212. [PMID: 37434410 DOI: 10.1002/ejhf.2972] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 07/02/2023] [Accepted: 07/09/2023] [Indexed: 07/13/2023] Open
Abstract
The development of the foetal heart is driven by increased glucose uptake and activation of mammalian target of rapamycin (mTOR) and hypoxia-inducible factor-1α (HIF-1α), which drives glycolysis. In contrast, the healthy adult heart is governed by sirtuin-1 (SIRT1) and adenosine monophosphate-activated protein kinase (AMPK), which promote fatty-acid oxidation and the substantial mitochondrial ATP production required for survival in a high-workload normoxic environment. During cardiac injury, the heart recapitulates the foetal signalling programme, which (although adaptive in the short term) is highly deleterious if sustained for long periods of time. Prolonged increases in glucose uptake in cardiomyocytes under stress leads to increased flux through the hexosamine biosynthesis pathway; its endproduct - uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) - functions as a critical nutrient surplus sensor. UDP-GlcNAc drives the post-translational protein modification known as O-GlcNAcylation, which rapidly and reversibly modifies thousands of intracellular proteins. Both O-GlcNAcylation and phosphorylation act at serine/threonine residues, but whereas phosphorylation is regulated by hundreds of specific kinases and phosphatases, O-GlcNAcylation is regulated by only two enzymes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA), which adds or removes GlcNAc (N-acetylglucosamine), respectively, from target proteins. Recapitulation of foetal programming in heart failure (regardless of diabetes) is accompanied by marked increases in O-GlcNAcylation, both experimentally and clinically. Heightened O-GlcNAcylation in the heart leads to impaired calcium kinetics and contractile derangements, arrhythmias related to activation of voltage-gated sodium channels and Ca2+ /calmodulin-dependent protein kinase II, mitochondrial dysfunction, and maladaptive hypertrophy, microvascular dysfunction, fibrosis and cardiomyopathy. These deleterious effects can be prevented by suppression of O-GlcNAcylation, which can be achieved experimentally by upregulation of AMPK and SIRT1 or by pharmacological inhibition of OGT or stimulation of OGA. The effects of sodium-glucose cotransporter 2 (SGLT2) inhibitors on the heart are accompanied by reduced O-GlcNAcylation, and their cytoprotective effects are reportedly abrogated if their action to suppress O-GlcNAcylation is blocked. Such an action may represent one of the many mechanisms by which enhanced AMPK and SIRT1 signalling following SGLT2 inhibition leads to cardiovascular benefits. These observations, taken collectively, suggest that UDP-GlcNAc functions as a critical nutrient surplus sensor (which acting in concert with mTOR and HIF-1α) can promote the development of cardiomyopathy.
Collapse
Affiliation(s)
- Milton Packer
- Baylor Heart and Vascular Institute, Dallas, TX, USA
- Imperial College, London, UK
| |
Collapse
|
3
|
Cogan KE, Carson BP, Patel B, Amigo-Benavent M, Jakeman PM, Egan B. Regulation of GLUT4 translocation in an in vitro cell model using postprandial human serum ex vivo. Exp Physiol 2019; 104:800-807. [PMID: 30864218 DOI: 10.1113/ep087356] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Accepted: 03/11/2019] [Indexed: 01/07/2023]
Abstract
NEW FINDINGS What is the research question? This study used a new experimental model, in which culture medium is conditioned with human serum ex vivo, to investigate nutrient-mediated regulation of GLUT4 translocation in skeletal muscle cells in vitro. What is the main finding and importance? Human serum stimulated GLUT4 translocation, an effect differentially modulated by whether the culture medium was conditioned with serum from fasted subjects or with serum collected after feeding of intact or hydrolysed whey protein. Conditioning cell culture medium with human serum ex vivo represents a new approach to elucidate the effects of ingesting specific nutrients on skeletal muscle cell metabolism. ABSTRACT Individual amino acids, amino acid mixtures and protein hydrolysates stimulate glucose uptake in many experimental models. To replicate better in vitro the dynamic postprandial response to feeding in vivo, in the present study we investigated the effects of culture media conditioned with fasted and postprandial human serum on GLUT4 translocation in L6-GLUT4myc myotubes. Serum samples were collected from healthy male participants (n = 8) at baseline (T0), 60 (T60) and 120 min (T120) after the ingestion of 0.33 g (kg body mass)-1 of intact (WPC) or hydrolysed (WPH) whey protein and an isonitrogenous non-essential amino acid (NEAA) control. L6-GLUT4myc myotubes were starved of serum and amino acids for 1 h before incubation for 1 h in medium containing 1% postprandial human serum, after which GLUT4 translocation was determined via colorimetric assay. Medium conditioned with fasted human serum at concentrations of 5-20% increased cell surface GLUT4myc abundance. Incubation with serum collected after the ingestion of WPH increased cell surface GLUT4myc at T60 relative to T0 [mean (lower, upper 95% confidence interval)]; [1.13 (1.05, 1.22)], whereas WPC [0.98 (0.90, 1.07)] or NEAA [1.02 (0.94, 1.11)] did not. The differential increases in cell surface GLUT4myc abundance were not explained by differences in serum concentrations of total, essential and branched-chain amino acids or insulin, glucagon-like peptide 1 (GLP-1) and gastric inhibitory polypeptide (GIP). Using a new ex vivo, in vitro approach, cell culture medium conditioned with postprandial serum after the ingestion of a whey protein hydrolysate increased GLUT4 translocation in skeletal muscle cells.
Collapse
Affiliation(s)
- Karl E Cogan
- Institute for Sport and Health, University College Dublin, Dublin, Ireland.,Food for Health Ireland, University College Dublin, Dublin, Ireland
| | - Brian P Carson
- Food for Health Ireland, University College Dublin, Dublin, Ireland.,Department of Physical Education & Sport Sciences, Faculty of Education and Health Sciences, University of Limerick, Limerick, Ireland.,Health Research Institute, University of Limerick, Limerick, Ireland
| | - Bijal Patel
- Food for Health Ireland, University College Dublin, Dublin, Ireland.,Department of Physical Education & Sport Sciences, Faculty of Education and Health Sciences, University of Limerick, Limerick, Ireland
| | - Miryam Amigo-Benavent
- Food for Health Ireland, University College Dublin, Dublin, Ireland.,Department of Physical Education & Sport Sciences, Faculty of Education and Health Sciences, University of Limerick, Limerick, Ireland
| | - Philip M Jakeman
- Food for Health Ireland, University College Dublin, Dublin, Ireland.,Department of Physical Education & Sport Sciences, Faculty of Education and Health Sciences, University of Limerick, Limerick, Ireland.,Centre for Intervention in Infection, Inflammation and Immunity (4i), University of Limerick, Limerick, Ireland
| | - Brendan Egan
- Food for Health Ireland, University College Dublin, Dublin, Ireland.,School of Health and Human Performance, Dublin City University, Dublin, Ireland.,National Institute for Cellular Biotechnology, Dublin City University, Dublin, Ireland
| |
Collapse
|
4
|
Bhute VJ, Ma Y, Bao X, Palecek SP. The Poly (ADP-Ribose) Polymerase Inhibitor Veliparib and Radiation Cause Significant Cell Line Dependent Metabolic Changes in Breast Cancer Cells. Sci Rep 2016; 6:36061. [PMID: 27811964 PMCID: PMC5095763 DOI: 10.1038/srep36061] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 10/04/2016] [Indexed: 12/22/2022] Open
Abstract
Breast tumors are characterized into subtypes based on their surface marker expression, which affects their prognosis and treatment. Poly (ADP-ribose) polymerase (PARP) inhibitors have shown promising results in clinical trials, both as single agents and in combination with other chemotherapeutics, in several subtypes of breast cancer patients. Here, we used NMR-based metabolomics to probe cell line-specific effects of the PARP inhibitor Veliparib and radiation on metabolism in three breast cancer cell lines. Our data reveal several cell line-independent metabolic changes upon PARP inhibition. Pathway enrichment and topology analysis identified that nitrogen metabolism, glycine, serine and threonine metabolism, aminoacyl-tRNA biosynthesis and taurine and hypotaurine metabolism were enriched after PARP inhibition in all three breast cancer cell lines. Many metabolic changes due to radiation and PARP inhibition were cell line-dependent, highlighting the need to understand how these treatments affect cancer cell response via changes in metabolism. Finally, both PARP inhibition and radiation induced a similar metabolic responses in BRCA-mutant HCC1937 cells, but not in MCF7 and MDAMB231 cells, suggesting that radiation and PARP inhibition share similar interactions with metabolic pathways in BRCA mutant cells. Our study emphasizes the importance of differences in metabolic responses to cancer treatments in different subtypes of cancers.
Collapse
Affiliation(s)
- Vijesh J Bhute
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Yan Ma
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Xiaoping Bao
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Sean P Palecek
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| |
Collapse
|
5
|
Ouro A, Arana L, Gangoiti P, Rivera IG, Ordoñez M, Trueba M, Lankalapalli RS, Bittman R, Gomez-Muñoz A. Ceramide 1-phosphate stimulates glucose uptake in macrophages. Cell Signal 2013; 25:786-95. [PMID: 23333242 DOI: 10.1016/j.cellsig.2013.01.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 12/28/2012] [Accepted: 01/07/2013] [Indexed: 12/24/2022]
Abstract
It is well established that ceramide 1-phosphate (C1P) is mitogenic and antiapoptotic, and that it is implicated in the regulation of macrophage migration. These activities require high energy levels to be available in cells. Macrophages obtain most of their energy from glucose. In this work, we demonstrate that C1P enhances glucose uptake in RAW264.7 macrophages. The major glucose transporter involved in this action was found to be GLUT 3, as determined by measuring its translocation from the cytosol to the plasma membrane. C1P-stimulated glucose uptake was blocked by selective inhibitors of phosphatidylinositol 3-kinase (PI3K) or Akt, also known as protein kinase B (PKB), and by specific siRNAs to silence the genes encoding for these kinases. C1P-stimulated glucose uptake was also inhibited by pertussis toxin (PTX) and by the siRNA that inhibited GLUT 3 expression. C1P increased the affinity of the glucose transporter for its substrate, and enhanced glucose metabolism to produce ATP. The latter action was also inhibited by PI3K- and Akt-selective inhibitors, PTX, or by specific siRNAs to inhibit GLUT 3 expression.
Collapse
Affiliation(s)
- Alberto Ouro
- Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), 48080 Bilbao, Spain
| | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Blumenthal J, Behar L, Elliott E, Ginzburg I. Dcp1a phosphorylation along neuronal development and stress. FEBS Lett 2008; 583:197-201. [PMID: 19084008 DOI: 10.1016/j.febslet.2008.12.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2008] [Revised: 11/21/2008] [Accepted: 12/01/2008] [Indexed: 11/18/2022]
Abstract
Decapping protein 1a (Dcp1a) is found in P-bodies and functions in mRNA cap removal prior to its degradation. The function and binding partners of Dcp1a have been thoroughly studied, however its expression pattern is still unclear. In this study we have monitored Dcp1a expression along brain development, neuronal differentiation and during cellular stress. We found that Dcp1a is hyperphosphorylated under these physiological conditions. We followed our observations and identified the specific amino acid residues that are phosphorylated. These findings suggest a novel post-translational modification that may influence the function of Dcp1a in response to various physiological cues.
Collapse
Affiliation(s)
- Jacob Blumenthal
- Department of Neurobiology, Weizmann Institute of Science, 76100 Rehovot, Israel.
| | | | | | | |
Collapse
|
7
|
Paul DS, Hernández-Zavala A, Walton FS, Adair BM, dina JD, Matoušek T, Stýblo M. Examination of the effects of arsenic on glucose homeostasis in cell culture and animal studies: development of a mouse model for arsenic-induced diabetes. Toxicol Appl Pharmacol 2007; 222:305-14. [PMID: 17336358 PMCID: PMC2680915 DOI: 10.1016/j.taap.2007.01.010] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2006] [Revised: 01/05/2007] [Accepted: 01/12/2007] [Indexed: 12/19/2022]
Abstract
Previous epidemiologic studies found increased prevalences of type 2 diabetes mellitus in populations exposed to high levels of inorganic arsenic (iAs) in drinking water. Although results of epidemiologic studies in low-exposure areas or occupational settings have been inconclusive, laboratory research has shown that exposures to iAs can produce effects that are consistent with type 2 diabetes. The current paper reviews the results of laboratory studies that examined the effects of iAs on glucose metabolism and describes new experiments in which the diabetogenic effects of iAs exposure were reproduced in a mouse model. Here, weanling male C57BL/6 mice drank deionized water with or without the addition of arsenite (25 or 50 ppm As) for 8 weeks. Intraperitoneal glucose tolerance tests revealed impaired glucose tolerance in mice exposed to 50 ppm As, but not to 25 ppm As. Exposure to 25 and 50 ppm As in drinking-water resulted in proportional increases in the concentration of iAs and its metabolites in the liver and in organs targeted by type 2 diabetes, including pancreas, skeletal muscle and adipose tissue. Dimethylarsenic was the predominant form of As in the tissues of mice in both 25 and 50 ppm groups. Notably, the average concentration of total speciated arsenic in livers from mice in the 50 ppm group was comparable to the highest concentration of total arsenic reported in the livers of Bangladeshi residents who had consumed water with an order of magnitude lower level of iAs. These data suggest that mice are less susceptible than humans to the diabetogenic effects of chronic exposure to iAs due to a more efficient clearance of iAs or its metabolites from target tissues.
Collapse
Affiliation(s)
- David S. Paul
- Department of Nutrition, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599
| | - Araceli Hernández-Zavala
- Center for Environmental Medicine, Asthma, and Lung Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599
| | - Felecia S. Walton
- Department of Nutrition, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599
| | - Blakely M. Adair
- Experimental Toxicology Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, 27711
| | - Jiří D dina
- Academy of Sciences of the Czech Republic, Institute of Analytical Chemistry, Laboratory of Trace Element Analysis, Vídeňská 1083, CZ-142 20 Prague, Czech Republic
| | - Tomáš Matoušek
- Academy of Sciences of the Czech Republic, Institute of Analytical Chemistry, Laboratory of Trace Element Analysis, Vídeňská 1083, CZ-142 20 Prague, Czech Republic
| | - Miroslav Stýblo
- Department of Nutrition, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599
- Center for Environmental Medicine, Asthma, and Lung Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599
| |
Collapse
|
8
|
Paul DS, Harmon AW, Devesa V, Thomas DJ, Stýblo M. Molecular mechanisms of the diabetogenic effects of arsenic: inhibition of insulin signaling by arsenite and methylarsonous acid. ENVIRONMENTAL HEALTH PERSPECTIVES 2007; 115:734-42. [PMID: 17520061 PMCID: PMC1867998 DOI: 10.1289/ehp.9867] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2006] [Accepted: 01/29/2007] [Indexed: 04/14/2023]
Abstract
BACKGROUND Increased prevalences of diabetes mellitus have been reported among individuals chronically exposed to inorganic arsenic (iAs). However, the mechanisms underlying the diabetogenic effects of iAs have not been characterized. We have previously shown that trivalent metabolites of iAs, arsenite (iAs(III)) and methylarsonous acid (MAs(III)) inhibit insulin-stimulated glucose uptake (ISGU) in 3T3-L1 adipocytes by suppressing the insulin-dependent phosphorylation of protein kinase B (PKB/Akt). OBJECTIVES Our goal was to identify the molecular mechanisms responsible for the suppression of PKB/Akt phosphorylation by iAs(III) and MAs(III). METHODS The effects of iAs(III) and MAs(III) on components of the insulin-activated signal transduction pathway that regulate PKB/Akt phosphorylation were examined in 3T3-L1 adipocytes. RESULTS Subtoxic concentrations of iAs(III) or MAs(III) had little or no effect on the activity of phosphatidylinositol 3-kinase (PI-3K), which synthesizes phosphatidylinositol-3,4,5-triphosphate (PIP(3)), or on phosphorylation of PTEN (phosphatase and tensin homolog deleted on chromosome ten), a PIP(3) phosphatase. Neither iAs(III) nor MAs(III) interfered with the phosphorylation of 3-phosphoinositide-dependent kinase-1 (PDK-1) located downstream from PI-3K. However, PDK-1 activity was inhibited by both iAs(III) and MAs(III). Consistent with these findings, PDK-1-catalyzed phosphorylation of PKB/Akt(Thr308) and PKB/Akt activity were suppressed in exposed cells. In addition, PKB/Akt(Ser473) phosphorylation, which is catalyzed by a putative PDK-2, was also suppressed. Notably, expression of constitutively active PKB/Akt restored the normal ISGU pattern in adipocytes treated with either iAs(III) or MAs(III). CONCLUSIONS These results suggest that inhibition of the PDK-1/PKB/Akt-mediated transduction step is the key mechanism for the inhibition of ISGU in adipocytes exposed to iAs(III) or MAs(III), and possibly for impaired glucose tolerance associated with human exposures to iAs.
Collapse
Affiliation(s)
- David S Paul
- Department of Nutrition, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7461, USA.
| | | | | | | | | |
Collapse
|
9
|
Zachara NE, Hart GW. Cell signaling, the essential role of O-GlcNAc! Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:599-617. [PMID: 16781888 DOI: 10.1016/j.bbalip.2006.04.007] [Citation(s) in RCA: 293] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2005] [Revised: 04/20/2006] [Accepted: 04/24/2006] [Indexed: 11/28/2022]
Abstract
An increasing body of evidence points to a central regulatory role for glucose in mediating cellular processes and expands the role of glucose well beyond its traditional role(s) in energy metabolism. Recently, it has been recognized that one downstream effector produced from glucose is UDP-GlcNAc. Levels of UDP-GlcNAc, and the subsequent addition of O-linked beta-N-acetylglucosamine (O-GlcNAc) to Ser/Thr residues, is involved in regulating nuclear and cytoplasmic proteins in a manner analogous to protein phosphorylation. O-GlcNAc protein modification is essential for life in mammalian cells, highlighting the importance of this simple post-translational modification in basic cellular regulation. Recent research has highlighted key roles for O-GlcNAc serving as a nutrient sensor in regulating insulin signaling, the cell cycle, and calcium handling, as well as the cellular stress response.
Collapse
Affiliation(s)
- Natasha E Zachara
- Department of Biological Chemistry, Johns Hopkins Singapore, 31 Biopolis Way, #02-01 The Nanos, 138669 Singapore
| | | |
Collapse
|
10
|
Navas-Acien A, Silbergeld EK, Streeter RA, Clark JM, Burke TA, Guallar E. Arsenic exposure and type 2 diabetes: a systematic review of the experimental and epidemiological evidence. ENVIRONMENTAL HEALTH PERSPECTIVES 2006; 114:641-8. [PMID: 16675414 PMCID: PMC1459913 DOI: 10.1289/ehp.8551] [Citation(s) in RCA: 245] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
Chronic arsenic exposure has been suggested to contribute to diabetes development. We performed a systematic review of the experimental and epidemiologic evidence on the association of arsenic and type 2 diabetes. We identified 19 in vitro studies of arsenic and glucose metabolism. Five studies reported that arsenic interfered with transcription factors involved in insulin-related gene expression: upstream factor 1 in pancreatic beta-cells and peroxisome proliferative-activated receptor gamma in preadipocytes. Other in vitro studies assessed the effect of arsenic on glucose uptake, typically using very high concentrations of arsenite or arsenate. These studies provide limited insight on potential mechanisms. We identified 10 in vivo studies in animals. These studies showed inconsistent effects of arsenic on glucose metabolism. Finally, we identified 19 epidemiologic studies (6 in high-arsenic areas in Taiwan and Bangladesh, 9 in occupational populations, and 4 in other populations). In studies from Taiwan and Bangladesh, the pooled relative risk estimate for diabetes comparing extreme arsenic exposure categories was 2.52 (95% confidence interval, 1.69-3.75), although methodologic problems limit the interpretation of the association. The evidence from occupational studies and from general populations other than Taiwan or Bangladesh was inconsistent. In summary, the current available evidence is inadequate to establish a causal role of arsenic in diabetes. Because arsenic exposure is widespread and diabetes prevalence is reaching epidemic proportions, experimental studies using arsenic concentrations relevant to human exposure and prospective epidemiologic studies measuring arsenic biomarkers and appropriately assessing diabetes should be a research priority.
Collapse
Affiliation(s)
- Ana Navas-Acien
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205-2223, USA.
| | | | | | | | | | | |
Collapse
|
11
|
Tawakol A, Migrino RQ, Hoffmann U, Abbara S, Houser S, Gewirtz H, Muller JE, Brady TJ, Fischman AJ. Noninvasive in vivo measurement of vascular inflammation with F-18 fluorodeoxyglucose positron emission tomography. J Nucl Cardiol 2005; 12:294-301. [PMID: 15944534 DOI: 10.1016/j.nuclcard.2005.03.002] [Citation(s) in RCA: 208] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND Fluorine 18 fluorodeoxyglucose (FDG) has been shown to accumulate in inflamed tissues. However, it is not known whether vascular inflammation can be measured noninvasively. The aim of this study was to test the hypothesis that vascular inflammation can be measured noninvasively by use of positron emission tomography (PET) with FDG. METHODS AND RESULTS Inflamed atherosclerotic lesions were induced in 9 male New Zealand white rabbits via balloon injury of the aortoiliac arterial segment and exposure to a high cholesterol diet. Ten rabbits fed standard chow served as controls. Three to six months after balloon injury, the rabbits were injected with FDG (1 mCi/kg), after which aortic uptake of FDG was assessed (3 hours after injection). Biodistribution of FDG activity within aortic segments was obtained by use of standard well gamma counting. FDG uptake was also determined noninvasively in a subset of 6 live atherosclerotic rabbits and 5 normal rabbits, via PET imaging and measurement of standardized uptake values over the abdominal aorta. Plaque macrophage density and smooth muscle cell density were determined by planimetric analysis of RAM-11 and smooth muscle actin staining, respectively. Biodistribution of FDG within nontarget organs was similar between atherosclerotic and control rabbits. However, well counter measurements of FDG uptake were significantly higher within atherosclerotic aortas compared with control aortas (P < .001). Within the upper abdominal aorta of the atherosclerotic group (area of greatest plaque formation), there was an approximately 19-fold increase in FDG uptake compared with controls (108.9 +/- 55.6 percent injected dose [%ID]/g x 10(3) vs 5.7 +/- 1.2 %ID/g x 10(3) [mean +/- SEM], P < .001). In parallel with these findings, FDG uptake, as determined by PET, was higher in atherosclerotic aortas (standardized uptake value for atherosclerotic aortas vs control aortas, 0.68 +/- 0.06 vs 0.13 +/- 0.01; P < .001). Moreover, macrophage density, assessed histologically, correlated with noninvasive (PET) measurements of FDG uptake (r = 0.93, P < .0001). In contrast to this finding, FDG uptake did not correlate with either aortic wall thickness or smooth muscle cell staining of the specimens. CONCLUSION These data show that FDG accumulates in macrophage-rich atherosclerotic plaques and demonstrate that vascular macrophage activity can be quantified noninvasively with FDG-PET. As such, measurement of vascular FDG uptake with PET holds promise for the noninvasive characterization of vascular inflammation.
Collapse
Affiliation(s)
- Ahmed Tawakol
- Department of Medicine (Cardiac Unit), Massachusetts General Hospital and Harvard Medical School, Boston 02114, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Zachara NE, O'Donnell N, Cheung WD, Mercer JJ, Marth JD, Hart GW. Dynamic O-GlcNAc modification of nucleocytoplasmic proteins in response to stress. A survival response of mammalian cells. J Biol Chem 2004; 279:30133-42. [PMID: 15138254 DOI: 10.1074/jbc.m403773200] [Citation(s) in RCA: 471] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cellular response to environmental, physiological, or chemical stress is key to survival following injury or disease. Here we describe a unique signaling mechanism by which cells detect and respond to stress in order to survive. A wide variety of stress stimuli rapidly increase nucleocytoplasmic protein modification by O-linked beta-N-acetylglucosamine (O-GlcNAc), an essential post-translational modification of Ser and Thr residues of metazoans. Blocking this post-translational modification, or reducing it, renders cells more sensitive to stress and results in decreased cell survival; and increasing O-GlcNAc levels protects cells. O-GlcNAc regulates both the rates and extent of the stress-induced induction of heat shock proteins, providing a molecular basis for these findings.
Collapse
Affiliation(s)
- Natasha E Zachara
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2185, USA
| | | | | | | | | | | |
Collapse
|
13
|
Al-Khalili L, Cartee GD, Krook A. RNA interference-mediated reduction in GLUT1 inhibits serum-induced glucose transport in primary human skeletal muscle cells. Biochem Biophys Res Commun 2003; 307:127-32. [PMID: 12849991 DOI: 10.1016/s0006-291x(03)01124-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Using RNA interference (RNAi), we specifically down-regulate protein expression in differentiated human skeletal myotube cultures. Serum stimulation of myotubes increases glucose uptake. Using a sensitive photolabeling technique, we demonstrate that this increase in glucose uptake is accompanied by increased cell-surface content of glucose transporter (GLUT) 1. Using RNAi, we specifically reduce GLUT1 mRNA and protein expression, leading to inhibition of serum-mediated increase in glucose transport. Thus, we demonstrate the utility of RNAi in a primary human differentiated cell system, and apply this methodology to demonstrate that serum-mediated increase in glucose transport in human skeletal muscle cells is dependent on GLUT1.
Collapse
Affiliation(s)
- Lubna Al-Khalili
- Department of Surgical Science, Karolinska Institute, S-171 77, Stockholm, Sweden
| | | | | |
Collapse
|
14
|
Haberkorn U, Altmann A. Imaging Techniques for Gene Therapy: SPECT, PET, and MRI. J Pharm Pract 2001. [DOI: 10.1106/eqat-deqg-6hr6-11h3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Gene therapy by the transfer and expression of suicide genes is performed using genes coding for nonmammalian enzymes that transform nontoxic prodrugs into toxic metabolites. Employing radiolabeled specific substrates and scintigraphic procedures to determine the functional activity of the recombinant enzyme in vivo, a therapeutic window of maximal gene expression and consecutive drug administration may be defined. If the gene therapy approach is based on the transduction of receptor genes, the recombinant gene expression in tumor cells can be monitored with radiolabeled ligands. Transfer of transporter genes as the sodium iodide transporter may also lead to the visualization of transduction via accumulation of iodide or pertechnetate. Furthermore, imaging based on transchelation of oxotechnetate to a polypeptide motif from a biocompatible complex with a higher dissociation constant than that of a diglycilcysteine complex or tyrosinase gene transfer for metal ion scavenging have been described. In addition, therapy effects may be assessed by the evaluation of the morphological changes of the tumor using magnetic resonance imaging or, more effectively, by the measurement of changes in metabolism with positron emission tomography employing tracers of tumor metabolism and proliferation. Finally, enzyme or receptor genes may serve as noninvasive reporter genes, if applied in the context of bicistronic vectors leading to coexpression of the therapeutic gene and the noninvasive reporter gene.
Collapse
Affiliation(s)
- Uwe Haberkorn
- Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center, Department of Nuclear Medicine, University of Heidelberg, Im Neuenheimer Feld 400, FRG-69120 Heidelberg, Germany,
| | - Annette Altmann
- Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center, Department of Nuclear Medicine, University of Heidelberg, Im Neuenheimer Feld 400, FRG-69120 Heidelberg, Germany
| |
Collapse
|
15
|
Dickman KG, Hempson SJ, Anderson J, Lippe S, Zhao L, Burakoff R, Shaw RD. Rotavirus alters paracellular permeability and energy metabolism in Caco-2 cells. Am J Physiol Gastrointest Liver Physiol 2000; 279:G757-66. [PMID: 11005763 DOI: 10.1152/ajpgi.2000.279.4.g757] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Rotaviruses infect epithelial cells of the small intestine, but the pathophysiology of the resulting severe diarrhea is incompletely understood. Histological damage to intestinal epithelium is not a consistent feature, and in vitro studies showed that intestinal cells did not undergo rapid death and lysis during viral replication. We show that rotavirus infection of Caco-2 cells caused disruption of tight junctions and loss of transepithelial resistance (TER) in the absence of cell death. TER declined from 300 to 22 Omega. cm(2) between 8 and 24 h after infection and was accompanied by increased transepithelial permeability to macromolecules of 478 and 4,000 Da. Distribution of tight junction proteins claudin-1, occludin, and ZO-1 was significantly altered during infection. Claudin-1 redistribution was notably apparent at the onset of the decline in TER. Infection was associated with increased production of lactate, decreased mitochondrial oxygen consumption, and reduced cellular ATP (60% of control at 24 h after infection), conditions known to reduce the integrity of epithelial tight junctions. In conclusion, these data show that rotavirus infection of Caco-2 intestinal cells altered tight junction structure and function, which may be a response to metabolic dysfunction.
Collapse
Affiliation(s)
- K G Dickman
- Research Service, Department of Veterans Affairs Medical Center, Northport, New York 11768, USA
| | | | | | | | | | | | | |
Collapse
|
16
|
Toussaint O, Medrano EE, von Zglinicki T. Cellular and molecular mechanisms of stress-induced premature senescence (SIPS) of human diploid fibroblasts and melanocytes. Exp Gerontol 2000; 35:927-45. [PMID: 11121681 DOI: 10.1016/s0531-5565(00)00180-7] [Citation(s) in RCA: 463] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Replicative senescence of human diploid fibroblasts (HDFs) or melanocytes is caused by the exhaustion of their proliferative potential. Stress-induced premature senescence (SIPS) occurs after many different sublethal stresses including H(2)O(2), hyperoxia, or tert-butylhydroperoxide. Cells in replicative senescence share common features with cells in SIPS: morphology, senescence-associated beta-galactosidase activity, cell cycle regulation, gene expression and telomere shortening. Telomere shortening is attributed to the accumulation of DNA single-strand breaks induced by oxidative damage. SIPS could be a mechanism of accumulation of senescent-like cells in vivo. Melanocytes exposed to sublethal doses of UVB undergo SIPS. Melanocytes from dark- and light- skinned populations display differences in their cell cycle regulation. Delayed SIPS occurs in melanocytes from light-skinned populations since a reduced association of p16(Ink-4a) with CDK4 and reduced phosphorylation of the retinoblastoma protein are observed. The role of reactive oxygen species in melanocyte SIPS is unclear. Both replicative senescence and SIPS are dependent on two major pathways. One is triggered by DNA damage, telomere damage and/or shortening and involves the activation of the p53 and p21(waf-1) proteins. The second pathway results in the accumulation of p16(Ink-4a) with the MAP kinase signalling pathway as possible intermediate. These data corroborate the thermodynamical theory of ageing, according to which the exposure of cells to sublethal stresses of various natures can trigger SIPS, with possible modulations of this process by bioenergetics.
Collapse
Affiliation(s)
- O Toussaint
- Laboratory of Cellular Biochemistry & Biology, Department of Biology, University of Namur (FUNDP), 61, Rue de Bruxelles, B-5000 Namur, Belgium.
| | | | | |
Collapse
|
17
|
Fladeby C, Serck-Hanssen G. Stress-induced glucose uptake in bovine chromaffin cells: a comparison of the effect of arsenite and anisomycin. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1452:313-21. [PMID: 10590320 DOI: 10.1016/s0167-4889(99)00145-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The effect of the toxic chemical Na-arsenite and the protein synthesis inhibitor anisomycin on glucose transport in primary cultures of bovine chromaffin cells was compared using the effect of insulin-like growth factor I (IGF-I) as a reference. The enhanced uptake of glucose obtained in response to arsenite and anisomycin reached maximum after 60 min, with the response to anisomycin being delayed in onset relative to that of arsenite. At maximal doses the arsenite effect was consistently higher than that of anisomycin and comparable to the approximately 2-fold effect produced by IGF-I. The selective inhibitor of stress-activated protein kinase 2 (SAPK2), SB 203580, inhibited completely anisomycin-induced glucose uptake but only partly suppressed uptake stimulated by arsenite. Both substances, in concentrations producing maximal effects on glucose transport, led to a strong phosphorylation of SAPK2. In contrast to the effect on glucose transport, the arsenite-induced phosphorylation of SAPK2 was relatively slow compared to the anisomycin-induced activation. The results indicate that glucose uptake induced by the two types of cellular stress are mediated by at least two different signaling pathways, which also differ from that activated by IGF-I.
Collapse
Affiliation(s)
- C Fladeby
- Department of Physiology, University of Bergen, Arstadveien 19, 5009, Bergen, Norway.
| | | |
Collapse
|
18
|
Kubasova T, Petcu I, Pfüller U, Köteles GJ. Effects of mistletoe lectin I and ionizing radiation on the glucose and thymidine uptake in tumour cells in vitro. Phytother Res 1999; 13:655-9. [PMID: 10594933 DOI: 10.1002/(sici)1099-1573(199912)13:8<655::aid-ptr517>3.0.co;2-n] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The increased uptake of hexose by mammalian cells is considered to be a general response to stress. Nowadays, mistletoe lectin separated from the extracts of the European mistletoe (Viscum album L.) is often used in adjuvant cancer therapy. The present work studies the effect of the lectin on unirradiated and x-irradiated tumour cells. The response of cultured human lung carcinoma cells (Calu-1) was followed by radioactive glucose uptake as well as by tritiated thymidine incorporation. The cells were maintained either in a complete or a so-called restrictive medium. Slight metabolic changes were found in the restrictive medium but not in the complete one. Mistletoe lectin I at a very low concentration (0.001 ng/mL) increased the glucose uptake and thymidine incorporation. Ionizing radiation (1 Gy) did not influence the hexose uptake but it enhanced the incorporation of thymidine. It seems that the actions of two different factors (mistletoe lectin I and radiation) proved to be rather provoking stress effects for the tumour cells as detected in the restrictive medium.
Collapse
Affiliation(s)
- T Kubasova
- Frédéric Joliot-Curie National Research Institute for Radiobiology and Radiohygiene, Budapest, P.O. Box 101, H-1775 Hungary
| | | | | | | |
Collapse
|
19
|
Haberkorn U. Monitoring of gene transfer for cancer therapy with radioactive isotopes. Ann Nucl Med 1999; 13:369-77. [PMID: 10656269 DOI: 10.1007/bf03164929] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- U Haberkorn
- Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center, and University of Heidelberg, FRG.
| |
Collapse
|
20
|
Fiorentini D, Hakim G, Zambonin L, Landi L. The effect of oxygen radicals on rat thymocyte glucose transport is independent of the site of their generation. Free Radic Biol Med 1999; 26:661-8. [PMID: 10218655 DOI: 10.1016/s0891-5849(98)00255-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We studied the relationship between the site of production of oxygen radicals and their effect on a rat thymocyte functional activity, the glucose transport, measured using a radioactive analogue of glucose, 2-deoxy-glucose. We compared the effects of a hydrophilic thermolabile azo compound, mimicking a radical attack outside the cell, with the lipid-soluble cumene hydroperoxide, which initiates lipid peroxidation in cell membranes. Our results show that a low grade oxidative stress stimulated glucose uptake rapidly, independently of the site of radical generation. In the presence of the azocompound, glucose uptake increased smoothly, attaining its maximum extent within 1 h. In thymocytes treated with cumene hydroperoxide the rate of glucose transport increased suddenly and remained constant over 1 h. The effects of the radical donors on TBARS production and protein sulfhydryl groups content were also evaluated. In thymocytes treated with the azo derivative no lipid peroxidation was observed, but a slow decrease of protein thiol groups occurred; after the addition of cumene hydroperoxide sulfhydryl groups did not change and TBARS increased significantly. The water-soluble antioxidant Trolox was able to remove the glucose uptake increase induced by the hydrophilic initiator and to delay the loss of membrane integrity.
Collapse
Affiliation(s)
- D Fiorentini
- Dipartimento di Biochimica G. Moruzzi, Università di Bologna, Italy
| | | | | | | |
Collapse
|
21
|
Ahmed N, Berridge MV. Transforming oncogenes regulate glucose transport by increasing transporter affinity for glucose: contrasting effects of oncogenes and heat stress in a murine marrow-derived cell line. Life Sci 1998; 63:1887-903. [PMID: 9825767 DOI: 10.1016/s0024-3205(98)00465-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Transforming oncogenes often overcome the growth factor requirements of cells by activating growth factor signal transduction pathways. Increased energy utilization by transformed cells is a well known phenomenon, but whether glucose uptake is regulated at the level of the glucose transporter has not been clearly established. To determine whether cell transformation by specific oncogenes like, v-H-ras and v-abl affects the activation state of glucose transporters, bone marrow-derived IL-3-dependent 32D (clone3) cells transfected with temperature-sensitive ras and abl oncogenes were used to compare proliferative responses and glucose transporting ability of these cells with the parental cell line at permissive (32 degrees C) and non-permissive (40 degrees C) temperatures. Transformed cells showed elevated incorporation of [3H]thymidine and enhanced tyrosine kinase activity, both of which were abrogated in temperature-sensitive mutants maintained at the non-permissive temperature. Compared with control cells, 2-deoxy-D-[1-(3)H]glucose (2-DOG) uptake was not significantly different in transformed cells at the permissive temperature. However, transformation was associated with a 2-2.5-fold greater affinity of glucose transporters for glucose (Km) and this was reversed following treatment with tyrosine kinase inhibitor, genistein. Maximum velocity of glucose transport (Vmax) and membrane expression of transporters were reduced in oncogene-transformed cells. At the non-permissive temperature, glucose uptake was elevated in both control and oncogene-transformed cells. This increase in glucose transport was not associated with a change in transporter affinity for glucose, but increased Glut-1 expression was observed indicating a 'heat stress' effect that overrode the effects attributable to oncogene loss. The 'heat stress' effect was inhibited by protein synthesis inhibitor cycloheximide. These results provide evidence for intrinsic activation of glucose transporters by the transforming oncogenes ras and abl, and indicate that oncogenes and 'heat stress' regulate glucose transport by different mechanisms.
Collapse
Affiliation(s)
- N Ahmed
- Malaghan Institute of Medical Research, Wellington School of Medicine, Wellington South, New Zealand.
| | | |
Collapse
|
22
|
Waki A, Fujibayashi Y, Yokoyama A. Recent advances in the analyses of the characteristics of tumors on FDG uptake. Nucl Med Biol 1998; 25:589-92. [PMID: 9804038 DOI: 10.1016/s0969-8051(98)00047-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- A Waki
- Biomedical Imaging Research Center, Fukui Medical University, Japan.
| | | | | |
Collapse
|
23
|
Toussaint O, Schneider ED. The thermodynamics and evolution of complexity in biological systems. Comp Biochem Physiol A Mol Integr Physiol 1998; 120:3-9. [PMID: 9773494 DOI: 10.1016/s1095-6433(98)10002-8] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Recent advances in nonequilibrium thermodynamics leads to the conclusion that similar processes, constrained by the second law of thermodynamics, give rise to the emergence of structure and process in a broad class of dissipative systems. The second law suggests that, in systems moved away from equilibrium, processes can emerge so that the system organizes in a way that reduces the effect of the applied gradient. If dynamic and or kinetic conditions permit, self organization processes can be expected. As biosystems grow and develop, they should increase their total dissipation, and develop more complex structures with more energy flow, increase their cycling activity, develop greater diversity and generate more hierarchical levels. As a corollary to this general statement, biosystems which do not increase their total dissipation, are organisms dedicated to death, like observed during the aging of any biosystem. Species which survive in ecosystems are those that funnel energy into their own production and reproduction and contribute to autocatalytic processes which increase the total dissipation of the ecosystem while at same time surviving within the constraints of their changing environment. In a broad class of biosystems, stress and aging have similar thermodynamic properties and suggests common underlying principles.
Collapse
Affiliation(s)
- O Toussaint
- Laboratory of Cellular Biochemistry and Biology, University of Namur, Belgium.
| | | |
Collapse
|
24
|
Acute Regulation of Glucose Transport After Activation of Human Peripheral Blood Neutrophils by Phorbol Myristate Acetate, fMLP, and Granulocyte-Macrophage Colony-Stimulating Factor. Blood 1998. [DOI: 10.1182/blood.v91.2.649.649_649_655] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Activation of human peripheral blood neutrophils by pathogens or by phorbol myristate acetate (PMA), fMLP, or myeloid growth factors generates a respiratory burst in which superoxide production plays an important role in killing invading microorganisms. Although the increased energy demands of activated neutrophils would be expected to be associated with increased glucose uptake and utilization, previous studies have shown that PMA inhibits 2-deoxyglucose (2-DOG) uptake. In this study, we show that PMA activation of neutrophils, isolated by methods not involving hypotonic lysis, increases the rate of 2-DOG uptake and results in a 1.6-fold to 2.1-fold increase in transporter affinity for glucose without changing Vmax. Increased transporter affinity in response to PMA was also observed with 3-O-methyglucose, which is not phosphorylated, and inclusion of glucose in the activation medium further increased respiratory burst activity. Increased 2-DOG uptake and increased transporter affinity for glucose were also observed with the peptide activator, fMLP, and with granulocyte-macrophage colony-stimulating factor (GM-CSF). The protein kinase C (PKC) inhibitor, calphostin C, and the tyrosine kinase inhibitor, genistein, inhibited both PMA- and fMLP-stimulated 2-DOG uptake. In contrast, genistein inhibited fMLP-induced superoxide production, but had little effect on the PMA-induced response, while staurosporine differentially inhibited PMA-induced superoxide production. These results show that neutrophil activation involves increased glucose transport and intrinsic activation of glucose transporter molecules. Both tyrosine kinases and PKC are implicated in the activation process.
Collapse
|
25
|
Acute Regulation of Glucose Transport After Activation of Human Peripheral Blood Neutrophils by Phorbol Myristate Acetate, fMLP, and Granulocyte-Macrophage Colony-Stimulating Factor. Blood 1998. [DOI: 10.1182/blood.v91.2.649] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractActivation of human peripheral blood neutrophils by pathogens or by phorbol myristate acetate (PMA), fMLP, or myeloid growth factors generates a respiratory burst in which superoxide production plays an important role in killing invading microorganisms. Although the increased energy demands of activated neutrophils would be expected to be associated with increased glucose uptake and utilization, previous studies have shown that PMA inhibits 2-deoxyglucose (2-DOG) uptake. In this study, we show that PMA activation of neutrophils, isolated by methods not involving hypotonic lysis, increases the rate of 2-DOG uptake and results in a 1.6-fold to 2.1-fold increase in transporter affinity for glucose without changing Vmax. Increased transporter affinity in response to PMA was also observed with 3-O-methyglucose, which is not phosphorylated, and inclusion of glucose in the activation medium further increased respiratory burst activity. Increased 2-DOG uptake and increased transporter affinity for glucose were also observed with the peptide activator, fMLP, and with granulocyte-macrophage colony-stimulating factor (GM-CSF). The protein kinase C (PKC) inhibitor, calphostin C, and the tyrosine kinase inhibitor, genistein, inhibited both PMA- and fMLP-stimulated 2-DOG uptake. In contrast, genistein inhibited fMLP-induced superoxide production, but had little effect on the PMA-induced response, while staurosporine differentially inhibited PMA-induced superoxide production. These results show that neutrophil activation involves increased glucose transport and intrinsic activation of glucose transporter molecules. Both tyrosine kinases and PKC are implicated in the activation process.
Collapse
|
26
|
Ahmed N, Kansara M, Berridge MV. Acute regulation of glucose transport in a monocyte-macrophage cell line: Glut-3 affinity for glucose is enhanced during the respiratory burst. Biochem J 1997; 327 ( Pt 2):369-75. [PMID: 9359403 PMCID: PMC1218803 DOI: 10.1042/bj3270369] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Activation of the respiratory burst imposes acute metabolic demands on phagocytic cells. These are met by mobilizing internal energy stores and by increasing the utilization of exogenous energy, including glucose in the circulation. To determine whether the increased glucose uptake that is known to be associated with the respiratory burst involves the regulation of glucose transporter molecules, the intrinsic transport properties of glucose transporters on the macrophage cell line RAW 264.7 were determined after activation with PMA, N-formyl-methionine-leucine-phenylalanine (fMLP) and the cytokines granulocyte/macrophage colony-stimulating factor (GM-CSF) and interleukin 3 (IL-3). Treatment with PMA resulted in a 2-fold increase in respiratory burst activity within 10 min; this was associated with a 30-50% increase in 2-deoxyglucose uptake and a 4-fold increase in transporter affinity for glucose. Similarly, fMLP, GM-CSF and IL-3 treatments stimulated 2-deoxyglucose uptake that was associated with a 3-4-fold increase in transporter affinity for glucose. To determine whether the changes observed in 2-deoxyglucose uptake in response to PMA, fMLP and growth factors were influenced by phosphorylation of the sugar, 3-O-methylglucose, which is not phosphorylated, was used. Increased 3-O-methylglucose uptake and increased transporter affinity for glucose were also observed after PMA, fMLP and GM-CSF treatments. Whereas both fMLP and GM-CSF stimulated superoxide production, IL-3 failed to activate respiratory burst activity. The protein kinase inhibitors genistein and staurosporine inhibited the increase in 2-deoxyglucose uptake observed with fMLP and GM-CSF, and partly reversed the affinity increase towards that of untreated control cells. In contrast, the phosphatidylinositol 3-kinase inhibitor wortmannin had little effect on 2-deoxyglucose uptake in response to these activators. Western blotting with subtype-specific antisera showed that Glut-3 was the predominant transporter on RAW 264.7 cells. These studies demonstrate that acute regulation of glucose transporters occurs in response to activators that promote respiratory burst activity, and show that this regulation involves both tyrosine kinases and protein kinase C activity.
Collapse
Affiliation(s)
- N Ahmed
- Malaghan Institute of Medical Research, Wellington School of Medicine, P.O. Box 7060, Wellington South, New Zealand
| | | | | |
Collapse
|
27
|
McDowell HE, Walker T, Hajduch E, Christie G, Batty IH, Downes CP, Hundal HS. Inositol phospholipid 3-kinase is activated by cellular stress but is not required for the stress-induced activation of glucose transport in L6 rat skeletal muscle cells. EUROPEAN JOURNAL OF BIOCHEMISTRY 1997; 247:306-13. [PMID: 9249041 DOI: 10.1111/j.1432-1033.1997.00306.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A characteristic response of cells subjected to a stress stimulus is a rapid activation of cellular glucose transport. The mechanisms governing this increase in glucose transport are poorly understood, but it has been suggested that the response may involve the intracellular-signaling components that also participate in the hormonal activation of glucose transport. In skeletal muscle and fat tissue, inositol phospholipid 3-kinase plays an integral role in the regulation of both basal and insulin-stimulated glucose transport. In this study, we have investigated whether inositol phospholipid 3-kinase is activated by chemical stress and, if so, whether it has a role to play in the stress-induced increase in glucose transport in L6 muscle cells. Furthermore, we have attempted to assess the basis by which inositol phospholipid 3-kinase may participate in the regulation of basal glucose transport. Acute exposure (30 min) of L6 muscle cells to 0.5 mM arsenite induced an 80% stimulation in glucose transport. This activation was due to a rise in the number of cell-surface glucose transporters, based on an increase in the Vmax of glucose transport and the observation that arsenite increases the plasma membrane content of GLUT1 and GLUT4 glucose transporters by 95% and 60%, respectively, from an intracellular compartment. Arsenite induced rapid activation (< 2 min) of inositol phospholipid 3-kinase with an approximately fourfold increase in phosphatidylinositol 3,4,5-trisphosphate (PtdIns3,4,5P3). In contrast, phosphatidylinositol 3-phosphate (PtdIns3P) levels were unaffected. Prior treatment of L6 cells with 100 nM wortmannin suppressed the arsenite-induced increase in PtdIns3,4,5P3 and reduced the cellular content of PtdIns3P by 50%. Under these conditions however, wortmannin failed to prevent the stress-induced activation of glucose transport, but suppressed basal glucose transport by 60% with an IC50 of about 10 nM. In the absence of arsenite, wortmannin caused a dose-dependent inhibition in the cellular levels of PtdIns3P and PtdIns3,4,5P3 with IC50 values of about 10 nM and 100 nM, respectively. In summary, the present results demonstrate that chemical stress activates inositol phospholipid 3-kinase and glucose transport in L6 muscle cells, but unlike the hormonal responses of these cells the activation of inositol phospholipid 3-kinase is not responsible for the stress-induced increase in glucose transport. This implies that stress-induced and hormonal stimulated increases in PtdIns3,4,5P3 levels are functionally distinct. By contrast, the maintenance of PtdIns3P levels, presumably involving a PtdIns-specific, wortmannin-sensitive inositol phospholipid 3-kinase may be required to support basal glucose transport.
Collapse
Affiliation(s)
- H E McDowell
- Department of Anatomy and Physiology, The University of Dundee, UK
| | | | | | | | | | | | | |
Collapse
|
28
|
Furuta M, Hasegawa M, Hayakawa K, Yamakawa M, Ishikawa H, Nonaka T, Mitsuhashi N, Niibe H. Rapid rise in FDG uptake in an irradiated human tumour xenograft. EUROPEAN JOURNAL OF NUCLEAR MEDICINE 1997; 24:435-8. [PMID: 9096096 DOI: 10.1007/bf00881817] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In order to investigate early changes in the glucose metabolism of irradiated tumours, tumour uptake of 2-[18F]fluoro-2-deoxy-d-glucose (18FDG) was studied in human tumour xenografts. Three human tumour lines [ependymoblastoma (NNE), small cell lung cancer (GLS), and glioblastoma (KYG)] showing different radiosensitivities and incidences of radiation-induced apoptosis were subcutaneously transplanted into nude mice, and were irradiated at a single dose of 10 Gy. Then 0.5 mCi of 18FDG was intravenously administered 1 h before sacrifice. The animals were sacrificed at 2, 4 and 6 h following irradiation, and 18FDG accumulation in the tumours was examined. Before irradiation, GLS and KYG tumours showed significantly higher rates of 18FDG accumulation compared with NNE tumours (P <0.004 and P <0.001, respectively). NNE (the most radiosensitive tumour with the highest incidence of radiation-induced apoptosis), however, displayed a 2.3-fold higher rate of 18FDG accumulation at 2 h following irradiation compared with a non-irradiated group (P <0.01), and thereafter showed a plateau up to 6 h. The accumulation did not increase significantly in the other tumours with lower radiosensitivity and much less radiation-induced apoptosis. The rapidity of the increase in 18FDG accumulation in the most radiosensitive tumour line, occurring as early as 2 h following irradiation, suggests that the increase was independent of recovery phenomena following radiation damage.
Collapse
Affiliation(s)
- M Furuta
- Department of Radiology and Radiation Oncology, Gunma University School of Medicine, Japan
| | | | | | | | | | | | | | | |
Collapse
|
29
|
Boyer S, Sharp PA, Debnam ES, Baldwin SA, Srai SK. Streptozotocin diabetes and the expression of GLUT1 at the brush border and basolateral membranes of intestinal enterocytes. FEBS Lett 1996; 396:218-22. [PMID: 8914990 DOI: 10.1016/0014-5793(96)01102-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Changes in membrane expression of sodium-dependent glucose transporter (SGLT1) and glucose transporter isoform (GLUT2) protein have been implicated in the increased intestinal glucose transport in streptozotocin-diabetes. The possible involvement of GLUT1 in the transport response, however, has not previously been studied. Using confocal microscopy on tissue sections and Western blotting of purified brush border membrane (BBM) and basolateral membrane (BLM), we have examined enterocyte expression of GLUT1 in untreated and in 1 and 21 day streptozotocin diabetic rats. In control enterocytes, GLUT1 was absent at the BBM and detected at low levels at the BLM. Diabetes resulted in a 4- to 5-fold increased expression of GLUT1 at the BLM and the protein could also be readily detected at the BBM. Insulin treatment of diabetic rats increased GLUT1 level at the BBM but was without effect on expression of the protein at the BLM.
Collapse
Affiliation(s)
- S Boyer
- Department of Biochemistry and Molecular Biology, University of Leeds, UK
| | | | | | | | | |
Collapse
|
30
|
Schaider H, Haberkorn U, Berger MR, Oberdorfer F, Morr I, van Kaick G. Application of alpha-aminoisobutyric acid, L-methionine, thymidine and 2-fluoro-2-deoxy-D-glucose to monitor effects of chemotherapy in a human colon carcinoma cell line. EUROPEAN JOURNAL OF NUCLEAR MEDICINE 1996; 23:55-60. [PMID: 8586103 DOI: 10.1007/bf01736990] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Up to 4 h after treatment of human SW 707 colon carcinoma cells with the antineoplastic drug 4-amino-N-(2'-aminophenyl)-benzamide (GOE 1734, dinaline), the effects of tumour cell metabolism and proliferation were examined in vitro. Four tracers which can be labelled with isotopes suitable for positron emission tomography (PET) were used for this purpose: alpha-aminoisobutyric acid (AIB) and methionine to study changes in amino acid transport and protein synthesis, thymidine to observe changes in tumour proliferation and 2-fluoro-2-deoxy-D-glucose (FDG) to estimate glucose metabolism. Dinaline showed an inhibition of the sodium-dependent and -independent uptake of AIB. The methionine uptake was found to increase shortly after therapy. Thymidine incorporation into DNA was impaired and the FDG uptake showed a maximally 2.2-fold enhancement. Inhibition of AIB uptake suggests changes in amino acid transport, whereas increased uptake of methionine and FDG points to an enhancement of protein synthesis and glycolysis caused by repair mechanisms. The cytostatic and antiproliferative effect of dinaline, observed in cell growth curves, could be demonstrated by the impaired thymidine incorporation into DNA. This study demonstrates that in vitro screening with radiotracers suitable for PET can help to clarify effects of new antineoplastic substances on tumour cell metabolism. These data may be applied to choose the appropriate time schedule for monitoring therapeutic effects on tumour tissue.
Collapse
Affiliation(s)
- H Schaider
- Department of Dermatology, Karl-Franzens University, Auenbruggerplatz 8, A-8036 Graz, Austria
| | | | | | | | | | | |
Collapse
|
31
|
Widnell CC. Control of glucose transport by GLUT1: regulated secretion in an unexpected environment. Biosci Rep 1995; 15:427-43. [PMID: 9156574 DOI: 10.1007/bf01204347] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Studies designed to elucidate the mechanism of regulation of the GLUT1 isoform of the glucose transporter in response to a variety of cellular stresses are reviewed. Using ts mutants of vesicular stomatitis virus, it was shown that the viral L gene was responsible for the stimulation of glucose transport in infected cells. Immunofluorescence of GLUT1 demonstrated that the increase in glucose transport was the consequence of a translocation of the transporter from a reservoir in cytoplasmic vesicles to the plasma membrane. When cells were cycled between deficient and standard medium, the change in glucose transport rates was paralleled by a cycling of the transporter between the plasma membrane and the cytoplasmic vesicles. The redistribution of GLUT1 was not a consequence of a general redistribution of recycling plasma membrane proteins. Instead, the findings focus attention on the regulated exocytosis of specific membrane constituents in cells that, until recently, were not thought to exhibit this capacity.
Collapse
Affiliation(s)
- C C Widnell
- Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine, PA 15261, USA
| |
Collapse
|
32
|
Vann JM, Goldman AJ, Szurek PF, Brooks BR. Deoxyglucose uptake by mouse astrocytes: effects of temperature and retrovirus infection. Neurochem Res 1995; 20:1013-20. [PMID: 8570004 DOI: 10.1007/bf00995554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Deoxyglucose uptake by FVB/N mouse astrocytes was studied before and after infection by ts1 retrovirus which causes a neurodegenerative disease in mice similar to HIV-1 encephalopathy in man. The Michaelis-Menten kinetic parameters, Km and Vmax, of 2-deoxy-D-glucose uptake by brain and cerebellar astrocytes were measured following culture at 34 degrees C where ts1 retrovirus replicates optimally, and at 37 degrees C. Compared to astrocytes cultured at 37 degrees C, astrocytes cultured at 34 degrees C had increased Km and decreased deoxyglucose uptake despite increased or unchanged Vmax. Following ts1 retrovirus infection, brain astrocyte deoxyglucose uptake doubled [132%] associated with decreased Km but unchanged Vmax, whereas cerebellar astrocyte deoxyglucose uptake doubled [102%] associated with increased Vmax but unchanged Km. These observations of altered deoxyglucose uptake kinetic parameters following retrovirus infection indicate different neurochemical mechanisms for the regional variation in deoxyglucose uptake observed following retrovirus infection of the CNS in vivo.
Collapse
Affiliation(s)
- J M Vann
- Neurology Service, William S. Middleton Memorial Veterans Hospital, Madison, WI 53705-2286, USA
| | | | | | | |
Collapse
|
33
|
Barros LF, Marchant RB, Baldwin SA. Dissection of stress-activated glucose transport from insulin-induced glucose transport in mammalian cells using wortmannin and ML-9. Biochem J 1995; 309 ( Pt 3):731-6. [PMID: 7639686 PMCID: PMC1135693 DOI: 10.1042/bj3090731] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The signaling pathways responsible for the activation of glucose transport by insulin and by metabolic stress in mammalian cells were studied in Clone 9 cells and 3T3-L1 adipocytes. Exposure of both cell types to azide or insulin markedly increased their glucose uptake capacity (Vmax.) without affecting their apparent affinity for glucose (Km). The effects of azide and insulin were not additive. Wortmannin, a selective inhibitor of phosphatidylinositol (PI) 3-kinase, did not affect stimulation of transport by azide but inhibited insulin-induced glucose transport with a Ki of < 10 nM. ML-9, a putative mitogen-activated protein kinase inhibitor, was equipotent in its inhibition of azide- and insulin-stimulated glucose transport. These findings suggest that multiple signalling cascades are involved in the stimulation of glucose transport in mammalian cells and that PI 3-kinase, an essential link in the pathway by which insulin stimulates glucose transport, is not necessary for the activation of glucose uptake by metabolic stress.
Collapse
Affiliation(s)
- L F Barros
- Department of Biochemistry and Molecular Biology, University of Leeds, U.K
| | | | | |
Collapse
|
34
|
Schaider H, Haberkorn U, Petru E, Berger MR. Combination treatment based on metabolic effects of dinaline. J Cancer Res Clin Oncol 1995; 121:203-10. [PMID: 7751318 DOI: 10.1007/bf01366963] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The human colon carcinoma cell line SW 707 was exposed for up to 72 h to the new antineoplastic agent 4-amino-N-(2'-aminophenyl)benzamide (GOE 1734, dinaline). Thereafter, uptake measurements with fluorodeoxy-[14C]glucose (FdGlc) were performed and cell-cycle fractions as well as adenine nucleotide pools were determined by flow cytometry and HPLC. One day after a 24 h exposure to 20-540 microM dinaline a 2.0-to 2.5-fold enhancement of FdGlc uptake was observed, and the values after 48-h or 72-h incubations showed a 2.5- to 3.5-fold or a 2.0-fold increase respectively. For all periods of exposure a diminished S phase (3%-71% of control) was found initially after incubation, demonstrating the antiproliferative effect of dinaline, with total recovery after 1 day. Adenine nucleotide pools were not diminished concomitantly. The enhanced FdGlc uptake caused by dinaline was the basis for choosing 2-deoxyglucose (dGlc) as the combination partner, which acts as an antimetabolite to enzymes involved in glucose metabolism. Several combinations of dinaline and dGlc were analyzed for their effects on growth inhibition. Almost 50% additional decrease in cell number as compared to monotherapy with dinaline was found after coexposure to 12 mM dGlc and 20 microM dinaline 24 h after incubation. Similar effects were observed 2 days after incubation with the two drugs. After 3 days, the cell numbers reached monotherapy levels. Since the cytostatic effect of dinaline could be enhanced by dGlc although incubation with dGlc alone caused no changes in cell number, the combined effect of both agents is synergistic. These results imply that dinaline might have applications in combination treatment in vivo.
Collapse
Affiliation(s)
- H Schaider
- Department of Carcinogenesis and Chemotherapy, Germany Cancer Research Center, Heidelberg
| | | | | | | |
Collapse
|
35
|
Abstract
The in vitro aging of human fibroblasts has become a classical model for studying cellular aging. This model was lately redefined by showing that these cells represent a stem cell system in which they progressively pass through seven morphotypes. Experimental data showed that external conditions that can be considered as stresses for the cells, can modulate the genome expression by speeding up the passage of the cells from one morphotype to the other. In this article, we will interpret these observations from the point of view of the thermodynamics of far from equilibrium open systems, which shows the importance of the production and the use of energy, both responsible for the generation of a given amount of entropy production. In stable systems like these cell morphotypes, such a production is constant but external stresses can prematurely destabilize the steady state of entropy production and, in doing so, accelerate the process of aging. It is also predicted that cells submitted to a stress will use part of their energy in response to the stress. Some experimental data in favor of such an interpretation have been obtained and more will be presented here that show that both cell death and accelerated cell aging under stress are modulated by the level of energy metabolism. All theoretical and experimental arguments presented in this article will show that cellular aging is related to stress and also to energy production through a very elaborate system of regulatory processes necessary for the cell to survive and to perform specific functions according to its differentiated state. This regulatory system also permits the cell to adapt its response according to the intensity of external as well as internal challenges and one of these responses will influence the cellular aging rate.
Collapse
Affiliation(s)
- O Toussaint
- Laboratoire de Biochimie Cellulaire, Facultés Universitaires, Namur, Belgium
| | | | | | | |
Collapse
|
36
|
Abstract
Patients with sepsis, burn, or trauma commonly enter a hypermetabolic stress state that is associated with a number of alterations in carbohydrate metabolism. These alterations include enhanced peripheral glucose uptake and utilization, hyperlactatemia, increased glucose production, depressed glycogenesis, glucose intolerance, and insulin resistance. The hypermetabolic state is induced by the area of infection or injury as well as by organs involved in the immunologic response to stress; it generates a glycemic milieu that is directed toward satisfying an obligatory requirement for glucose as an energy substrate. This article reviews experimental and clinical data that indicate potential mechanisms for these alterations and emphasizes aspects that have relevance for the clinician.
Collapse
Affiliation(s)
- B A Mizock
- Department of Medicine, Chicago Medical School, Illinois
| |
Collapse
|
37
|
Kan O, Baldwin SA, Whetton AD. Apoptosis is regulated by the rate of glucose transport in an interleukin 3 dependent cell line. J Exp Med 1994; 180:917-23. [PMID: 8064240 PMCID: PMC2191668 DOI: 10.1084/jem.180.3.917] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
In the absence of a survival stimulus, the interleukin 3 (IL-3)-dependent IC.DP cell line undergoes a process termed programmed cell death or apoptosis. Survival can be induced by IL-3, which can also stimulate proliferation of IC.DP cells. IC.DP cells have been stably transfected with the p160v-abl protein tyrosine kinase, activation of the kinase at the permissive temperature permits cell survival in the absence of IL-3 by suppression of apoptosis, although the growth factor is still required for proliferation. Both IL-3 and activation of the v-ABL tyrosine kinase stimulated glucose transport, which may in part be due to a translocation of transporters to the cell surface. Inhibition of glucose uptake markedly increased the rate of apoptosis in these cells, an effect that could be reversed by the provision of alternative energy sources such as glutamine. Growth factor- or oncogene-mediated increases in glucose uptake may therefore represent an important regulatory point in the suppression of apoptosis.
Collapse
Affiliation(s)
- O Kan
- Department of Biochemistry and Applied Molecular Biology, UMIST, Manchester, United Kingdom
| | | | | |
Collapse
|
38
|
Haberkorn U, Oberdorfer F, Klenner T, Strauss LG, Stöhr M, Wallich R, Altmann A, Kaick GV. Metabolic and transcriptional changes in osteosarcoma cells treated with chemotherapeutic drugs. Nucl Med Biol 1994; 21:835-45. [PMID: 9234333 DOI: 10.1016/0969-8051(94)90163-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Two cell lines derived from a lung metastasis of a rat osteosarcoma were treated with cisplatin (CDDP) and two phosphonic acid compounds (AMDP, DADP), AMDP-treated cells showed a decrease in FDG uptake, CDDP and DADP resulted in an increase. A block in G2 or in S and G2 phase was seen after CDDP and AMDP treatment. The changes in the cell cycle fractions were not related to the changes in FDG uptake. Furthermore, the transcription of the glucose transporter and hexokinase genes were elevated in CDDP and decreased in AMDP treated cells. However, the changes in FDG uptake were not fully explained by changes at the transcriptional level. The total uptake of thymidine was elevated although the incorporation of thymidine into DNA decreased. In both cell lines the changes in FDG uptake correlated with the changes in thymidine incorporation into DNA (r = 0.95 and r = 0.83, respectively). Cells with an increased FDG uptake showed a weaker growth inhibition than cells with a decrease in FDG uptake.
Collapse
Affiliation(s)
- U Haberkorn
- Department of Oncologic Diagnosis and Therapy, German Cancer Research Center, Heidelberg, Germany
| | | | | | | | | | | | | | | |
Collapse
|
39
|
Toussaint O, Houbion A, Remacle J. Effects of modulations of the energetic metabolism on the mortality of cultured cells. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1186:209-20. [PMID: 8043593 DOI: 10.1016/0005-2728(94)90180-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Since cells are open systems which exchange material with their surroundings, they can be considered as open systems far from equilibrium and in this way, they follow the principles of thermodynamics of open systems. This approach stresses the fact that cells optimize their use of energy according to their functions. However, with time and/or under environmental challenges, cells can reorganize themselves at other lower levels of energy production and utilization (Toussaint et al. (1991) Mech. Ageing Dev. 61, 45-64). Considered as optimized systems, cells can adapt their behaviours according to the balance between, on one side, their energetic potential and the level of their defence systems, and on the other side, the intensity of the stress. Mainly three types of behaviour can be theoretically predicted. If the stresses are very low, the damages generated are instantaneously repaired and the cellular system remains at its steady state of energy production and utilization. If the stresses are of an intermediary intensity, it is predicted that the cell can leave its steady state of energy production and utilization and find a new one characterized by a lower level of entropy production and a higher level of errors. Third, if the stresses are of a very high intensity which can be cytotoxic, the level of the energetic potential of the cell is directly related to cell survival. We tested the latter prediction in the present work in two ways. First, the level of energy production was lowered by partially uncoupling the mitochondria. Then the effect of stresses under tert-butylhydroperoxide or ethanol was investigated in order to look for a synergistic effect on cell death with the mitochondria uncoupling. Secondly, the effect of a modification of the energetic sources during the stress was tested. Besides a protective effect found with specific defence systems, the presence of energetic metabolites such as D-glucose, pyruvate/malate, glutamate/malate, was tested and found to be protective. The effect of a stimulator of the energetic metabolism, naftidrofuryl oxalate, was also investigated and found protective. The experimental data provide good evidence that energetic factors can modulate the resistance of cells to various stresses.
Collapse
Affiliation(s)
- O Toussaint
- Laboratoire de Biochimie Cellulaire, Facultés Universitaires N.-D. de la Paix, Namur, Belgium
| | | | | |
Collapse
|
40
|
Baldwin SA. Mammalian passive glucose transporters: members of an ubiquitous family of active and passive transport proteins. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1154:17-49. [PMID: 8507645 DOI: 10.1016/0304-4157(93)90015-g] [Citation(s) in RCA: 225] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- S A Baldwin
- Department of Biochemistry and Molecular Biology, University of Leeds, UK
| |
Collapse
|