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Wong A, Sun Q, Latif II, Karwi QG. Metabolic flux in macrophages in obesity and type-2 diabetes. JOURNAL OF PHARMACY & PHARMACEUTICAL SCIENCES : A PUBLICATION OF THE CANADIAN SOCIETY FOR PHARMACEUTICAL SCIENCES, SOCIETE CANADIENNE DES SCIENCES PHARMACEUTIQUES 2024; 27:13210. [PMID: 38988822 PMCID: PMC11233469 DOI: 10.3389/jpps.2024.13210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Accepted: 06/14/2024] [Indexed: 07/12/2024]
Abstract
Recent literature extensively investigates the crucial role of energy metabolism in determining the inflammatory response and polarization status of macrophages. This rapidly expanding area of research highlights the importance of understanding the link between energy metabolism and macrophage function. The metabolic pathways in macrophages are intricate and interdependent, and they can affect the polarization of macrophages. Previous studies suggested that glucose flux through cytosolic glycolysis is necessary to trigger pro-inflammatory phenotypes of macrophages, and fatty acid oxidation is crucial to support anti-inflammatory responses. However, recent studies demonstrated that this understanding is oversimplified and that the metabolic control of macrophage polarization is highly complex and not fully understood yet. How the metabolic flux through different metabolic pathways (glycolysis, glucose oxidation, fatty acid oxidation, ketone oxidation, and amino acid oxidation) is altered by obesity- and type 2 diabetes (T2D)-associated insulin resistance is also not fully defined. This mini-review focuses on the impact of insulin resistance in obesity and T2D on the metabolic flux through the main metabolic pathways in macrophages, which might be linked to changes in their inflammatory responses. We closely evaluated the experimental studies and methodologies used in the published research and highlighted priority research areas for future investigations.
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Affiliation(s)
- Angela Wong
- Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Qiuyu Sun
- Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Ismail Ibrahim Latif
- Department of Microbiology, College of Medicine, University of Diyala, Baqubaa, Diyala, Iraq
| | - Qutuba G Karwi
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, Saint John's, NL, Canada
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Rho SB, Byun HJ, Kim BR, Lee CH. Liver Kinase B1 Mediates Its Anti-Tumor Function by Binding to the N-Terminus of Malic Enzyme 3. Biomol Ther (Seoul) 2023; 31:330-339. [PMID: 37095735 PMCID: PMC10129855 DOI: 10.4062/biomolther.2023.041] [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: 03/01/2023] [Revised: 03/18/2023] [Accepted: 03/24/2023] [Indexed: 04/26/2023] Open
Abstract
Liver kinase B1 (LKB1) is a crucial tumor suppressor involved in various cellular processes, including embryonic development, tumor initiation and progression, cell adhesion, apoptosis, and metabolism. However, the precise mechanisms underlying its functions remain elusive. In this study, we demonstrate that LKB1 interacts directly with malic enzyme 3 (ME3) through the N-terminus of the enzyme and identified the binding regions necessary for this interaction. The binding activity was confirmed to promote the expression of ME3 in an LKB1-dependent manner and was also shown to induce apoptosis activity. Furthermore, LKB1 and ME3 overexpression upregulated the expression of tumour suppressor proteins (p53 and p21) and downregulated the expression of antiapoptotic proteins (nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and B-cell lymphoma 2 (Bcl-2)). Additionally, LKB1 and ME3 enhanced the transcription of p21 and p53 and inhibited the transcription of NF-κB. Moreover, LKB1 and ME3 suppressed the phosphorylation of various components of the phosphatidylinositol-4,5-bisphosphate 3-kinase/protein kinase B signaling pathway. Overall, these results suggest that LKB1 promotes pro-apoptotic activities by inducing ME3 expression.
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Affiliation(s)
- Seung Bae Rho
- Division of Cancer Biology, Research Institute, National Cancer Center, Goyang 10408
| | - Hyun Jung Byun
- College of Pharmacy, Dongguk University, Goyang 10326, Republic of Korea
| | - Boh-Ram Kim
- College of Pharmacy, Dongguk University, Goyang 10326, Republic of Korea
| | - Chang Hoon Lee
- College of Pharmacy, Dongguk University, Goyang 10326, Republic of Korea
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3
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Balas M, Popescu Din IM, Hermenean A, Cinteza LO, Dinischiotu A. Exposure to Iron Oxide Nanoparticles Coated with Phospholipid-Based Polymeric Micelles Induces Renal Transitory Biochemical and Histopathological Changes in Mice. MATERIALS (BASEL, SWITZERLAND) 2021; 14:2605. [PMID: 34067676 PMCID: PMC8156474 DOI: 10.3390/ma14102605] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 04/26/2021] [Accepted: 05/14/2021] [Indexed: 11/18/2022]
Abstract
The renal toxicity induced by the intravenously injected iron oxide nanoparticles (IONPs) encapsulated in phospholipid-based polymeric micelles was studied in CD1 mice for 2 weeks. Two doses of 5 and 15 mg of Fe/kg bodyweight of NPs or saline solution (control) were tested, and the levels of antioxidant enzyme activities, oxidative stress parameters, and the expressions of kidney fibrosis biomarkers were analyzed. The enzymatic activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase, glutathione reductase, and glucose-6-phosphate dehydrogenase in the kidney were significantly decreased compared to the control in the first 3 days followed by a recovery up to 14 days. Concomitantly, a significant increase in lipid peroxidation (malondialdehyde) levels and a decrease in protein thiol groups were recorded. Moreover, increases in the expressions of T cell immunoglobulin and mucin domain 1 (TIM-1) and transforming growth factor-β (TGF-β) were observed in mouse tissue samples in the first week, which were more pronounced for the higher dose. The results suggested the role of oxidative stress as a mechanism for induced toxicity in mice kidneys after the IV administration of IONPs encapsulated in phospholipid-based polymeric micelles but also the capacity of the kidneys' defense systems to revert efficiently the biochemical modifications that were moderate and for short duration.
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Affiliation(s)
- Mihaela Balas
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, 050095 Bucharest, Romania; (M.B.); (I.M.P.D.)
| | - Ioana Mihaela Popescu Din
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, 050095 Bucharest, Romania; (M.B.); (I.M.P.D.)
| | - Anca Hermenean
- Department of Experimental and Applied Biology, Institute of Life Sciences, Vasile Goldis Western University of Arad, 86 Rebreanu, 310414 Arad, Romania;
- Department of Histology, Faculty of Medicine, Vasile Goldis Western University of Arad, 1 Feleacului Street, 310396 Arad, Romania
| | - Ludmila Otilia Cinteza
- Department of Physical Chemistry, Faculty of Chemistry, University of Bucharest, 4-12 Regina Elisabeta Blvd, 030018 Bucharest, Romania;
| | - Anca Dinischiotu
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, 050095 Bucharest, Romania; (M.B.); (I.M.P.D.)
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Carvalho PLPF, Yamamoto FY, Barros MM, Gatlin Iii DM. l-glutamine in vitro supplementation enhances Nile tilapia Oreochromis niloticus (Linnaeus, 1758) leukocyte function. FISH & SHELLFISH IMMUNOLOGY 2018; 80:592-599. [PMID: 29960065 DOI: 10.1016/j.fsi.2018.06.043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 06/22/2018] [Accepted: 06/26/2018] [Indexed: 06/08/2023]
Abstract
Under appropriate conditions, glutamine (Gln) is an essential nutrient for immunological responses, acting as a metabolic substrate for proliferation of enterocytes and lymphocytes, and having positive effects on the function of stimulated immune cells. Thus, specific components of both innate and adaptive immune systems of Nile tilapia were evaluated after supplementing Gln to cell culture media. Primary cell cultures of kidney leukocytes were used for respiratory burst and phagocytic activity assessment. The ability of macrophages to kill Streptococcus iniae also was evaluated. Additionally, a proliferation assay was conducted with peripheral blood lymphocytes (PBL) exposed to non-specific mitogens. Results showed that macrophage phagocytosis, anion superoxide production, and bactericidal capacity were significantly (P < 0.05) enhanced by Gln supplementation to the culture media. The proliferation of lymphocytes upon mitogenic exposure also was significantly (P < 0.05) enhanced by Gln supplementation to the media. Our results suggest that in vitro, different levels of Gln were necessary for optimal immunological responses of leukocytes and lymphocytes. As such, Gln supplementation was able to enhance and modulate both innate and adaptive responses of Nile tilapia leukocytes, highlighting its potential application as an immunonutrient.
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Affiliation(s)
- Pedro L P F Carvalho
- Faculdade de Medicina Veterinária e Zootecnia, Departamento de Melhoramento e Nutrição Animal, Universidade Estadual Paulista "Júlio de Mesquita Filho", São Paulo, Brazil; Department of Wildlife and Fisheries Sciences, Texas A&M University System, College Station, TX, 77843-2258, USA.
| | - Fernando Y Yamamoto
- Department of Wildlife and Fisheries Sciences, Texas A&M University System, College Station, TX, 77843-2258, USA.
| | - Margarida M Barros
- Faculdade de Medicina Veterinária e Zootecnia, Departamento de Melhoramento e Nutrição Animal, Universidade Estadual Paulista "Júlio de Mesquita Filho", São Paulo, Brazil.
| | - Delbert M Gatlin Iii
- Department of Wildlife and Fisheries Sciences, Texas A&M University System, College Station, TX, 77843-2258, USA.
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Ježek P, Holendová B, Garlid KD, Jabůrek M. Mitochondrial Uncoupling Proteins: Subtle Regulators of Cellular Redox Signaling. Antioxid Redox Signal 2018; 29:667-714. [PMID: 29351723 PMCID: PMC6071544 DOI: 10.1089/ars.2017.7225] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
SIGNIFICANCE Mitochondria are the energetic, metabolic, redox, and information signaling centers of the cell. Substrate pressure, mitochondrial network dynamics, and cristae morphology state are integrated by the protonmotive force Δp or its potential component, ΔΨ, which are attenuated by proton backflux into the matrix, termed uncoupling. The mitochondrial uncoupling proteins (UCP1-5) play an eminent role in the regulation of each of the mentioned aspects, being involved in numerous physiological events including redox signaling. Recent Advances: UCP2 structure, including purine nucleotide and fatty acid (FA) binding sites, strongly support the FA cycling mechanism: UCP2 expels FA anions, whereas uncoupling is achieved by the membrane backflux of protonated FA. Nascent FAs, cleaved by phospholipases, are preferential. The resulting Δp dissipation decreases superoxide formation dependent on Δp. UCP-mediated antioxidant protection and its impairment are expected to play a major role in cell physiology and pathology. Moreover, UCP2-mediated aspartate, oxaloacetate, and malate antiport with phosphate is expected to alter metabolism of cancer cells. CRITICAL ISSUES A wide range of UCP antioxidant effects and participations in redox signaling have been reported; however, mechanisms of UCP activation are still debated. Switching off/on the UCP2 protonophoretic function might serve as redox signaling either by employing/releasing the extra capacity of cell antioxidant systems or by directly increasing/decreasing mitochondrial superoxide sources. Rapid UCP2 degradation, FA levels, elevation of purine nucleotides, decreased Mg2+, or increased pyruvate accumulation may initiate UCP-mediated redox signaling. FUTURE DIRECTIONS Issues such as UCP2 participation in glucose sensing, neuronal (synaptic) function, and immune cell activation should be elucidated. Antioxid. Redox Signal. 29, 667-714.
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Affiliation(s)
- Petr Ježek
- 1 Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences , Prague, Czech Republic
| | - Blanka Holendová
- 1 Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences , Prague, Czech Republic
| | - Keith D Garlid
- 2 UCLA Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA , Los Angeles, California
| | - Martin Jabůrek
- 1 Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences , Prague, Czech Republic
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Abstract
PURPOSE OF REVIEW Glucose 6-phosphate dehydrogenase (G6PD) is the rate-limiting enzyme of the pentose phosphate pathway. G6PD is the main source of the essential cellular reductant, NADPH. The purpose of this review is to describe the biochemistry of G6PD and NADPH, cellular factors that regulate G6PD, normal physiologic roles of G6PD, and the pathogenic role altered G6PD/NADPH plays in kidney disease. RECENT FINDINGS NADPH is required for many essential cellular processes such as the antioxidant system, nitric oxide synthase, cytochrome p450 enzymes, and NADPH oxidase. Decreased G6PD activity and, as a result, decreased NADPH level have been associated with diabetic kidney disease, altered nitric oxide production, aldosterone-mediated endothelial dysfunction, and dialysis-associated anemia. Increased G6PD activity is associated with all cancers including kidney cancer. Inherited G6PD deficiency is the most common mutation in the world that is thought to be a relatively mild disorder primarily associated with anemia. Yet, intriguing studies have shown an increased prevalence of diabetes mellitus in G6PD-deficient people. It is not known if G6PD-deficient people are at more risk for other diseases. SUMMARY Much more research needs to be done to determine the role of altered G6PD activity (inherited or acquired) in the pathogenesis of kidney disease.
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A past and present overview of macrophage metabolism and functional outcomes. Clin Sci (Lond) 2017; 131:1329-1342. [PMID: 28592702 DOI: 10.1042/cs20170220] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 03/16/2017] [Accepted: 03/22/2017] [Indexed: 12/11/2022]
Abstract
In 1986 and 1987, Philip Newsholme et al. reported macrophages utilize glutamine, as well as glucose, at high rates. These authors measured key enzyme activities and consumption and production levels of metabolites in incubated or cultured macrophages isolated from the mouse or rat intraperitoneal cavity. Metabolic pathways essential for macrophage function were then determined. Macrophages utilize glucose to generate (i) ATP in the pathways of glycolysis and mitochondrial oxidative phosphorylation, (ii) glycerol 3-phosphate for the synthesis of phospholipids and triacylglycerols, (iii) NADPH for the production of reactive oxygen species (ROS) and (iv) ribose for the synthesis of RNA and subsequently production and secretion of protein mediators (e.g. cytokines). Glutamine plays an essential role in macrophage metabolism and function, as it is required for energy production but also provides nitrogen for synthesis of purines, pyrimidines and thus RNA. Macrophages also utilize fatty acids for both energy production in the mitochondria and lipid synthesis essential to plasma membrane turnover and lipid meditator production. Recent studies utilizing metabolomic approaches, transcriptional and metabolite tracking technologies have detailed mitochondrial release of tricarboxylic acid (TCA) intermediates (e.g. citrate and succinate) to the cytosol, which then regulate pro-inflammatory responses. Macrophages can reprogramme their metabolism and function according to environmental conditions and stimuli in order to polarize phenotype so generating pro- or anti-inflammatory cells. Changes in macrophage metabolism result in modified function/phenotype and vice versa. The plasticity of macrophage metabolism allows the cell to quickly respond to changes in environmental conditions such as those induced by hormones and/or inflammation. A past and present overview of macrophage metabolism and impact of endocrine regulation and the relevance to human disease are described in this review.
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Sympathetic Nervous System Control of Carbon Tetrachloride-Induced Oxidative Stress in Liver through α-Adrenergic Signaling. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2016:3190617. [PMID: 26798417 PMCID: PMC4699022 DOI: 10.1155/2016/3190617] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 08/17/2015] [Accepted: 09/29/2015] [Indexed: 12/14/2022]
Abstract
In addition to being the primary organ involved in redox cycling, the liver is one of the most highly innervated tissues in mammals. The interaction between hepatocytes and sympathetic, parasympathetic, and peptidergic nerve fibers through a variety of neurotransmitters and signaling pathways is recognized as being important in the regulation of hepatocyte function, liver regeneration, and hepatic fibrosis. However, less is known regarding the role of the sympathetic nervous system (SNS) in modulating the hepatic response to oxidative stress. Our aim was to investigate the role of the SNS in healthy and oxidatively stressed liver parenchyma. Mice treated with 6-hydroxydopamine hydrobromide were used to realize chemical sympathectomy. Carbon tetrachloride (CCl4) injection was used to induce oxidative liver injury. Sympathectomized animals were protected from CCl4 induced hepatic lipid peroxidation-mediated cytotoxicity and genotoxicity as assessed by 4-hydroxy-2-nonenal levels, morphological features of cell damage, and DNA oxidative damage. Furthermore, sympathectomy modulated hepatic inflammatory response induced by CCl4-mediated lipid peroxidation. CCl4 induced lipid peroxidation and hepatotoxicity were suppressed by administration of an α-adrenergic antagonist. We conclude that the SNS provides a permissive microenvironment for hepatic oxidative stress indicating the possibility that targeting the hepatic α-adrenergic signaling could be a viable strategy for improving outcomes in patients with acute hepatic injury.
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Palmieri EM, Spera I, Menga A, Infantino V, Porcelli V, Iacobazzi V, Pierri CL, Hooper DC, Palmieri F, Castegna A. Acetylation of human mitochondrial citrate carrier modulates mitochondrial citrate/malate exchange activity to sustain NADPH production during macrophage activation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:729-38. [PMID: 25917893 DOI: 10.1016/j.bbabio.2015.04.009] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 03/27/2015] [Accepted: 04/18/2015] [Indexed: 01/22/2023]
Abstract
The mitochondrial citrate-malate exchanger (CIC), a known target of acetylation, is up-regulated in activated immune cells and plays a key role in the production of inflammatory mediators. However, the role of acetylation in CIC activity is elusive. We show that CIC is acetylated in activated primary human macrophages and U937 cells and the level of acetylation is higher in glucose-deprived compared to normal glucose medium. Acetylation enhances CIC transport activity, leading to a higher citrate efflux from mitochondria in exchange with malate. Cytosolic citrate levels do not increase upon activation of cells grown in deprived compared to normal glucose media, indicating that citrate, transported from mitochondria at higher rates from acetylated CIC, is consumed at higher rates. Malate levels in the cytosol are lower in activated cells grown in glucose-deprived compared to normal glucose medium, indicating that this TCA intermediate is rapidly recycled back into the cytosol where it is used by the malic enzyme. Additionally, in activated cells CIC inhibition increases the NADP+/NADPH ratio in glucose-deprived cells; this ratio is unchanged in glucose-rich grown cells due to the activity of the pentose phosphate pathway. Consistently, the NADPH-producing isocitrate dehydrogenase level is higher in activated glucose-deprived as compared to glucose rich cells. These results demonstrate that, in the absence of glucose, activated macrophages increase CIC acetylation to enhance citrate efflux from mitochondria not only to produce inflammatory mediators but also to meet the NADPH demand through the actions of isocitrate dehydrogenase and malic enzyme.
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Affiliation(s)
- Erika M Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari "Aldo Moro", Bari, Italy
| | - Iolanda Spera
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari "Aldo Moro", Bari, Italy
| | - Alessio Menga
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari "Aldo Moro", Bari, Italy
| | | | - Vito Porcelli
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari "Aldo Moro", Bari, Italy
| | - Vito Iacobazzi
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari "Aldo Moro", Bari, Italy; Center of Excellence in Comparative Genomics, University of Bari "Aldo Moro", Bari, Italy; CNR Institute of Biomembranes and Bioenergetics, Bari, Italy
| | - Ciro L Pierri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari "Aldo Moro", Bari, Italy
| | - Douglas C Hooper
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, USA; Department of Neurological Surgery, Thomas Jefferson University, Philadelphia, USA
| | - Ferdinando Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari "Aldo Moro", Bari, Italy; Center of Excellence in Comparative Genomics, University of Bari "Aldo Moro", Bari, Italy.
| | - Alessandra Castegna
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari "Aldo Moro", Bari, Italy; Center of Excellence in Comparative Genomics, University of Bari "Aldo Moro", Bari, Italy.
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Jiang P, Du W, Wu M. Regulation of the pentose phosphate pathway in cancer. Protein Cell 2014; 5:592-602. [PMID: 25015087 PMCID: PMC4112277 DOI: 10.1007/s13238-014-0082-8] [Citation(s) in RCA: 320] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 05/22/2014] [Indexed: 12/19/2022] Open
Abstract
Energy metabolism is significantly reprogrammed in many human cancers, and these alterations confer many advantages to cancer cells, including the promotion of biosynthesis, ATP generation, detoxification and support of rapid proliferation. The pentose phosphate pathway (PPP) is a major pathway for glucose catabolism. The PPP directs glucose flux to its oxidative branch and produces a reduced form of nicotinamide adenine dinucleotide phosphate (NADPH), an essential reductant in anabolic processes. It has become clear that the PPP plays a critical role in regulating cancer cell growth by supplying cells with not only ribose-5-phosphate but also NADPH for detoxification of intracellular reactive oxygen species, reductive biosynthesis and ribose biogenesis. Thus, alteration of the PPP contributes directly to cell proliferation, survival and senescence. Furthermore, recent studies have shown that the PPP is regulated oncogenically and/or metabolically by numerous factors, including tumor suppressors, oncoproteins and intracellular metabolites. Dysregulation of PPP flux dramatically impacts cancer growth and survival. Therefore, a better understanding of how the PPP is reprogrammed and the mechanism underlying the balance between glycolysis and PPP flux in cancer will be valuable in developing therapeutic strategies targeting this pathway.
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Affiliation(s)
- Peng Jiang
- School of Life Sciences, Tsinghua University, Beijing, 100084, China,
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Ho HY, Cheng ML, Chiu DTY. Glucose-6-phosphate dehydrogenase--beyond the realm of red cell biology. Free Radic Res 2014; 48:1028-48. [PMID: 24720642 DOI: 10.3109/10715762.2014.913788] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Glucose-6-phosphate dehydrogenase (G6PD) is critical to the maintenance of NADPH pool and redox homeostasis. Conventionally, G6PD deficiency has been associated with hemolytic disorders. Most biochemical variants were identified and characterized at molecular level. Recently, a number of studies have shone light on the roles of G6PD in aspects of physiology other than erythrocytic pathophysiology. G6PD deficiency alters the redox homeostasis, and affects dysfunctional cell growth and signaling, anomalous embryonic development, and altered susceptibility to infection. The present article gives a brief review of basic science and clinical findings about G6PD, and covers the latest development in the field. Moreover, how G6PD status alters the susceptibility of the affected individuals to certain degenerative diseases is also discussed.
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Affiliation(s)
- H-Y Ho
- Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University , Kwei-san, Tao-yuan , Taiwan
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12
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Kimmel DW, Meschievitz ME, Hiatt LA, Cliffel DE. Multianalyte Microphysiometry of Macrophage Responses to Phorbol Myristate Acetate, Lipopolysaccharide, and Lipoarabinomannan. ELECTROANAL 2013; 25:1706-1712. [PMID: 25798034 PMCID: PMC4365790 DOI: 10.1002/elan.201300121] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Accepted: 04/08/2013] [Indexed: 01/09/2023]
Abstract
This study examined the hypothesis that mycobacterial antigens generate different metabolic responses in macrophages as compared to gram-negative effectors and macrophage activators. The metabolic activation of macrophages by PMA is a useful tool for studying virulent agents and can be compared to other effectors. While phorbol myristate acetate (PMA) is commonly used to study macrophage activation, the concentration used to create this physiological response varies. The response of RAW-264.7 macrophages is concentration-dependent, where the metabolic response to high concentrations of PMA decreases suggesting deactivation. The gram-negative effector, lipopolysaccharide (LPS), was seen to promote glucose and oxygen production which were used to produce a delayed onset of oxidative burst. Pre-incubation with interferon-γ (IFN-γ) increased the effect on cell metabolism, where the synergistic effects of IFN-γ and LPS immediately initiated oxidative burst. These studies exhibited a stark contrast with lipoarabinomannan (LAM), an antigenic glycolipid component associated with the bacterial genus Mycobacterium. The presence of LAM effectively inhibits any metabolic response preventing consumption of glucose and oxygen for the promotion of oxidative burst and to ensure pathogenic proliferation. This study demonstrates for the first time the immediate inhibitory metabolic effects LAM has on macrophages, suggesting implications for future intervention studies with Mycobacterium tuberculosis.
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Affiliation(s)
| | | | | | - David E. Cliffel
- Corresponding Author: Department of Chemistry, Vanderbilt University, 7330 Stevenson Center, VU Station B 351822, Nashville, TN 37235-1822; Phone: (615) 343-3937;
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13
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Lama JL, Bell RAV, Storey KB. Glucose-6-phosphate dehydrogenase regulation in the hepatopancreas of the anoxia-tolerant marine mollusc, Littorina littorea. PeerJ 2013; 1:e21. [PMID: 23638356 PMCID: PMC3628605 DOI: 10.7717/peerj.21] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 01/08/2013] [Indexed: 12/14/2022] Open
Abstract
Glucose-6-phosphate dehydrogenase (G6PDH) gates flux through the pentose phosphate pathway and is key to cellular antioxidant defense due to its role in producing NADPH. Good antioxidant defenses are crucial for anoxia-tolerant organisms that experience wide variations in oxygen availability. The marine mollusc, Littorina littorea, is an intertidal snail that experiences daily bouts of anoxia/hypoxia with the tide cycle and shows multiple metabolic and enzymatic adaptations that support anaerobiosis. This study investigated the kinetic, physical and regulatory properties of G6PDH from hepatopancreas of L. littorea to determine if the enzyme is differentially regulated in response to anoxia, thereby providing altered pentose phosphate pathway functionality under oxygen stress conditions. Several kinetic properties of G6PDH differed significantly between aerobic and 24 h anoxic conditions; compared with the aerobic state, anoxic G6PDH (assayed at pH 8) showed a 38% decrease in Km G6P and enhanced inhibition by urea, whereas in pH 6 assays Km NADP and maximal activity changed significantly between the two states. The mechanism underlying anoxia-responsive changes in enzyme properties proved to be a change in the phosphorylation state of G6PDH. This was documented with immunoblotting using an anti-phosphoserine antibody, in vitro incubations that stimulated endogenous protein kinases versus protein phosphatases and significantly changed Km G6P, and phosphorylation of the enzyme with 32P-ATP. All these data indicated that the aerobic and anoxic forms of G6PDH were the high and low phosphate forms, respectively, and that phosphorylation state was modulated in response to selected endogenous protein kinases (PKA or PKG) and protein phosphatases (PP1 or PP2C). Anoxia-induced changes in the phosphorylation state of G6PDH may facilitate sustained or increased production of NADPH to enhance antioxidant defense during long term anaerobiosis and/or during the transition back to aerobic conditions when the reintroduction of oxygen causes a rapid increase in oxidative stress.
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Affiliation(s)
- Judeh L Lama
- Institute of Biochemistry and Department of Biology , Carleton University , Ottawa, Ontario , Canada K1S 5B6
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14
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Zhang Z, Yang Z, Zhu B, Hu J, Liew CW, Zhang Y, Leopold JA, Handy DE, Loscalzo J, Stanton RC. Increasing glucose 6-phosphate dehydrogenase activity restores redox balance in vascular endothelial cells exposed to high glucose. PLoS One 2012. [PMID: 23185302 PMCID: PMC3501497 DOI: 10.1371/journal.pone.0049128] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Previous studies have shown that high glucose increases reactive oxygen species (ROS) in endothelial cells that contributes to vascular dysfunction and atherosclerosis. Accumulation of ROS is due to dysregulated redox balance between ROS-producing systems and antioxidant systems. Previous research from our laboratory has shown that high glucose decreases the principal cellular reductant, NADPH by impairing the activity of glucose 6-phosphate dehydrogenase (G6PD). We and others also have shown that the high glucose-induced decrease in G6PD activity is mediated, at least in part, by cAMP-dependent protein kinase A (PKA). As both the major antioxidant enzymes and NADPH oxidase, a major source of ROS, use NADPH as substrate, we explored whether G6PD activity was a critical mediator of redox balance. We found that overexpression of G6PD by pAD-G6PD infection restored redox balance. Moreover inhibition of PKA decreased ROS accumulation and increased redox enzymes, while not altering the protein expression level of redox enzymes. Interestingly, high glucose stimulated an increase in NADPH oxidase (NOX) and colocalization of G6PD with NOX, which was inhibited by the PKA inhibitor. Lastly, inhibition of PKA ameliorated high glucose mediated increase in cell death and inhibition of cell growth. These studies illustrate that increasing G6PD activity restores redox balance in endothelial cells exposed to high glucose, which is a potentially important therapeutic target to protect ECs from the deleterious effects of high glucose.
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Affiliation(s)
- Zhaoyun Zhang
- Research Division, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts, United States of America
- Division of Endocrinology and Metabolism, Huashan Hospital, Shanghai, China
| | - Zhihong Yang
- Research Division, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Bo Zhu
- Division of Endocrinology and Metabolism, Nanfang Hospital, Guangzhou, China
| | - Ji Hu
- Division of Endocrinology and Metabolism, 2nd Affiliated Hospital of Soochow University, Suzhou, China
| | - Chong Wee Liew
- Research Division, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Yingyi Zhang
- Brigham Woman's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jane A. Leopold
- Brigham Woman's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Diane E. Handy
- Brigham Woman's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Joseph Loscalzo
- Brigham Woman's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Robert C. Stanton
- Research Division, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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Guerra B, Bolin A, Otton R. Carbonyl stress and a combination of astaxanthin/vitamin C induce biochemical changes in human neutrophils. Toxicol In Vitro 2012; 26:1181-90. [DOI: 10.1016/j.tiv.2012.06.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 06/15/2012] [Accepted: 06/22/2012] [Indexed: 10/28/2022]
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16
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Hammami I, Chen J, Bronte V, DeCrescenzo G, Jolicoeur M. L-glutamine is a key parameter in the immunosuppression phenomenon. Biochem Biophys Res Commun 2012; 425:724-9. [PMID: 22885179 DOI: 10.1016/j.bbrc.2012.07.139] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 07/25/2012] [Indexed: 02/07/2023]
Abstract
Suppression of tumour-specific T-cell functions by myeloid-derived suppressor cells (MDSCs) is a dominant mechanism of tumour escape. MDSCs express two enzymes, i.e. inducible nitric oxide synthase (iNOS) and arginase (ARG1), which metabolize the semi-essential amino acid L-arginine (L-Arg) whose bioavailability is crucial for T-cell proliferation and functions. Recently, we showed that glutaminolysis supports MDSC maturation process by ensuring the supply of intermediates and energy. In this work, we used an immortalized cell line derived from mouse MDSCs (MSC-1 cell line) to further investigate the role of L-glutamine (L-Gln) in the maintenance of MDSC immunosuppressive activity. Culturing MSC-1 cells in L-Gln-limited medium inhibited iNOS activity, while ARG1 was not affected. MSC-1 cells inhibited Jukat cell growth without any noticeable effect on their viability. The characterization of MSC-1 cell metabolic profile revealed that L-Gln is an important precursor of lactate production via the NADP(+)-dependent malic enzyme, which co-produces NADPH. Moreover, the TCA cycle activity was down-regulated in the absence of L-Gln and the cell bioenergetic status was deteriorated accordingly. This strongly suggests that iNOS activity, but not that of ARG1, is related to an enhanced central carbon metabolism and a high bioenergetic status. Taken altogether, our results suggest that the control of glutaminolysis fluxes may represent a valuable target for immunotherapy.
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Affiliation(s)
- Ines Hammami
- Department of Chemical Engineering, Ecole Polytechnique de Montréal, 2500 Chemin de Polytechnique, Montreal, Quebec, Canada H3T 1J4
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Hammami I, Chen J, Murschel F, Bronte V, De Crescenzo G, Jolicoeur M. Immunosuppressive activity enhances central carbon metabolism and bioenergetics in myeloid-derived suppressor cells in vitro models. BMC Cell Biol 2012; 13:18. [PMID: 22762146 PMCID: PMC3433355 DOI: 10.1186/1471-2121-13-18] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 07/04/2012] [Indexed: 01/10/2023] Open
Abstract
Background The tumor microenvironment contains a vast array of pro- and anti-inflammatory cytokines that alter myelopoiesis and lead to the maturation of immunosuppressive cells known as myeloid-derived suppressor cells (MDSCs). Incubating bone marrow (BM) precursors with a combination of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-6 (IL-6) generated a tumor-infiltrating MDSC-like population that impaired anti-tumor specific T-cell functions. This in vitro experimental approach was used to simulate MDSC maturation, and the cellular metabolic response was then monitored. A complementary experimental model that inhibited L-arginine (L-Arg) metabolizing enzymes in MSC-1 cells, an immortalized cell line derived from primary MDSCs, was used to study the metabolic events related to immunosuppression. Results Exposure of BM cells to GM-CSF and IL-6 activated, within 24 h, L-Arg metabolizing enzymes which are responsible for the MDSCs immunosuppressive potential. This was accompanied by an increased uptake of L-glutamine (L-Gln) and glucose, the latter being metabolized by anaerobic glycolysis. The up-regulation of nutrient uptake lead to the accumulation of TCA cycle intermediates and lactate as well as the endogenous synthesis of L-Arg and the production of energy-rich nucleotides. Moreover, inhibition of L-Arg metabolism in MSC-1 cells down-regulated central carbon metabolism activity, including glycolysis, glutaminolysis and TCA cycle activity, and led to a deterioration of cell bioenergetic status. The simultaneous increase of cell specific concentrations of ATP and a decrease in ATP-to-ADP ratio in BM-derived MDSCs suggested cells were metabolically active during maturation. Moreover, AMP-activated protein kinase (AMPK) was activated during MDSC maturation in GM-CSF and IL-6–treated cultures, as revealed by the continuous increase of AMP-to-ATP ratios and the phosphorylation of AMPK. Likewise, AMPK activity was decreased in MSC-1 cells when L-Arg metabolizing enzymes were inhibited. Finally, inhibition of AMPK activity by the specific inhibitor Compound C (Comp-C) resulted in the inhibition of L-Arg metabolizing enzyme activity and abolished MDSCs immunosuppressive activity. Conclusions We anticipate that the inhibition of AMPK and the control of metabolic fluxes may be considered as a novel therapeutic target for the recovery of the immunosurveillance process in cancer-bearing hosts.
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Affiliation(s)
- Ines Hammami
- Department of Chemical Engineering, Ecole Polytechnique de Montréal, 2500 Chemin de Polytechnique, H3T-1J4, Montreal, QC, Canada
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18
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Stanton RC. Glucose-6-phosphate dehydrogenase, NADPH, and cell survival. IUBMB Life 2012; 64:362-9. [PMID: 22431005 DOI: 10.1002/iub.1017] [Citation(s) in RCA: 431] [Impact Index Per Article: 35.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Accepted: 02/07/2012] [Indexed: 02/06/2023]
Abstract
Glucose-6-phosphate dehydrogenase (G6PD) is the rate-limiting enzyme of the pentose phosphate pathway. Many scientists think that the roles and regulation of G6PD in physiology and pathophysiology have been well established as the enzyme was first identified 80 years ago. And that G6PD has been extensively studied especially with respect to G6PD deficiency and its association with hemolysis, and with respect to the role G6PD plays in lipid metabolism. But there has been a growing understanding of the central importance of G6PD to cellular physiology as it is a major source of NADPH that is required by many essential cellular systems including the antioxidant pathways, nitric oxide synthase, NADPH oxidase, cytochrome p450 system, and others. Indeed G6PD is essential for cell survival. It has also become evident that G6PD is highly regulated by many signals that affect transcription, post-translation, intracellular location, and interactions with other protein. Pathophysiologic roles for G6PD have also been identified in such disease processes as diabetes, aldosterone-induced endothelial dysfunction, cancer, and others. It is now clear that G6PD is under complex regulatory control and of central importance to many cellular processes. In this review the biochemistry, regulatory signals, physiologic roles, and pathophysiologic roles for G6PD that have been elucidated over the past 20 years are discussed.
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Affiliation(s)
- Robert C Stanton
- Renal Section, Joslin Diabetes Center, and Harvard Medical School, Boston, MA 02215, USA.
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19
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Hiatt LA, McKenzie JR, Deravi LF, Harry RS, Wright DW, Cliffel DE. A printed superoxide dismutase coated electrode for the study of macrophage oxidative burst. Biosens Bioelectron 2012; 33:128-33. [PMID: 22257735 PMCID: PMC3291099 DOI: 10.1016/j.bios.2011.12.038] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Revised: 12/16/2011] [Accepted: 12/20/2011] [Indexed: 11/23/2022]
Abstract
The miniaturization of electrochemical sensors allows for the minimally invasive and cost effective examination of cellular responses at a high efficacy rate. In this work, an ink-jet printed superoxide dismutase electrode was designed, characterized, and utilized as a novel microfluidic device to examine the metabolic response of a 2D layer of macrophage cells. Since superoxide production is one of the first indicators of oxidative burst, macrophage cells were exposed within the microfluidic device to phorbol myristate acetate (PMA), a known promoter of oxidative burst, and the production of superoxide was measured. A 46 ± 19% increase in current was measured over a 30 min time period demonstrating successful detection of sustained macrophage oxidative burst, which corresponds to an increase in the superoxide production rate by 9 ± 3 attomoles/cell/s. Linear sweep voltammetry was utilized to show the selectivity of this sensor for superoxide over hydrogen peroxide. This novel controllable microfluidic system can be used to study the impact of multiple effectors from a large number of bacteria or other invaders along a 2D layer of macrophages, providing an in vitro platform for improved electrochemical studies of metabolic responses.
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Affiliation(s)
- Leslie A. Hiatt
- Department of Chemistry, Vanderbilt University, 7330 Stevenson Center, VU Station B 351822, Nashville, TN 37235-1822 USA
| | - Jennifer R. McKenzie
- Department of Chemistry, Vanderbilt University, 7330 Stevenson Center, VU Station B 351822, Nashville, TN 37235-1822 USA
| | - Leila F. Deravi
- Department of Chemistry, Vanderbilt University, 7330 Stevenson Center, VU Station B 351822, Nashville, TN 37235-1822 USA
| | - Reese S. Harry
- Department of Chemistry, Vanderbilt University, 7330 Stevenson Center, VU Station B 351822, Nashville, TN 37235-1822 USA
| | - David W. Wright
- Department of Chemistry, Vanderbilt University, 7330 Stevenson Center, VU Station B 351822, Nashville, TN 37235-1822 USA
| | - David E. Cliffel
- Department of Chemistry, Vanderbilt University, 7330 Stevenson Center, VU Station B 351822, Nashville, TN 37235-1822 USA
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20
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Robinson MA, Baumgardner JE, Otto CM. Oxygen-dependent regulation of nitric oxide production by inducible nitric oxide synthase. Free Radic Biol Med 2011; 51:1952-65. [PMID: 21958548 DOI: 10.1016/j.freeradbiomed.2011.08.034] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 08/29/2011] [Accepted: 08/30/2011] [Indexed: 12/19/2022]
Abstract
Inducible nitric oxide synthase (iNOS) catalyzes the reaction that converts the substrates O(2) and l-arginine to the products nitric oxide (NO) and l-citrulline. Macrophages, and many other cell types, upregulate and express iNOS primarily in response to inflammatory stimuli. Physiological and pathophysiological oxygen tension can regulate NO production by iNOS at multiple levels, including transcriptional, translational, posttranslational, enzyme dimerization, cofactor availability, and substrate dependence. Cell culture techniques that emphasize control of cellular PO(2), and measurement of NO or its stable products, have been used by several investigators for in vitro study of the O(2) dependence of NO production at one or more of these levels. In most cell types, prior or concurrent exposure to cytokines or other inflammatory stimuli is required for the upregulation of iNOS mRNA and protein by hypoxia. Important transcription factors that target the iNOS promoter in hypoxia include hypoxia-inducible factor 1 and/or nuclear factor κB. In contrast to the upregulation of iNOS by hypoxia, in most cell types NO production is reduced by hypoxia. Recent work suggests a prominent role for O(2) substrate dependence in the short-term regulation of iNOS-mediated NO production.
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Affiliation(s)
- Mary A Robinson
- Department of Clinical Studies, New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104-6010, USA
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21
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Impact of the carotenoid astaxanthin on phagocytic capacity and ROS/RNS production of human neutrophils treated with free fatty acids and high glucose. Int Immunopharmacol 2011; 11:2220-6. [DOI: 10.1016/j.intimp.2011.10.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Accepted: 10/04/2011] [Indexed: 01/08/2023]
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22
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Bourque S, Dutartre A, Hammoudi V, Blanc S, Dahan J, Jeandroz S, Pichereaux C, Rossignol M, Wendehenne D. Type-2 histone deacetylases as new regulators of elicitor-induced cell death in plants. THE NEW PHYTOLOGIST 2011; 192:127-139. [PMID: 21651563 DOI: 10.1111/j.1469-8137.2011.03788.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
• Plant resistance to pathogen attack is often associated with a localized programmed cell death called hypersensitive response (HR). How this cell death is controlled remains largely unknown. • Upon treatment with cryptogein, an elicitor of tobacco defence and cell death, we identified NtHD2a and NtHD2b, two redundant isoforms of type-2 nuclear histone deacetylases (HDACs). These HDACs are phosphorylated after a few minutes' treatment, and their rate of mRNAs are rapidly and strongly reduced, leading to a 40-fold decrease after 10 h of treatment. • By using HDAC inhibitors, RNAi- and overexpression-based approaches, we showed that HDACs, and especially NtHD2a/b, act as inhibitors of cryptogein-induced cell death. Moreover, in NtHD2a/b-silenced plants, infiltration with cryptogein led to HR-like symptoms in distal leaves. • Taken together, these results show for the first time that type-2 HDACs, which are specific to plants, act as negative regulators of elicitor-induced cell death in tobacco (Nicotiana tabacum), suggesting that the HR is controlled by post-translational modifications including (de)acetylation of nuclear proteins.
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Affiliation(s)
- Stéphane Bourque
- UMR INRA 1088/CNRS 5184/Université de Bourgogne Plante-Microbe-Environnement, 17 Rue Sully, BP 86510, 21065 Dijon cedex, France
- GDR CNRS N°2688 'Calcium et régulation de l'expression des gènes en contexte normal et pathologique', 31000 Toulouse, France
| | - Agnès Dutartre
- UMR INRA 1088/CNRS 5184/Université de Bourgogne Plante-Microbe-Environnement, 17 Rue Sully, BP 86510, 21065 Dijon cedex, France
| | - Valentin Hammoudi
- UMR INRA 1088/CNRS 5184/Université de Bourgogne Plante-Microbe-Environnement, 17 Rue Sully, BP 86510, 21065 Dijon cedex, France
| | - Sabrina Blanc
- UMR INRA 1088/CNRS 5184/Université de Bourgogne Plante-Microbe-Environnement, 17 Rue Sully, BP 86510, 21065 Dijon cedex, France
| | - Jennifer Dahan
- UMR INRA 1088/CNRS 5184/Université de Bourgogne Plante-Microbe-Environnement, 17 Rue Sully, BP 86510, 21065 Dijon cedex, France
| | - Sylvain Jeandroz
- UPSP PROXISS, AgroSup Dijon, 26 Boulevard du Dr Petitjean, BP 87999, 21079 Dijon cedex, France
| | - Carole Pichereaux
- Plateforme Protéomique Génopole Toulouse Midi-Pyrénées, Institut de Pharmacologie et de Biologie Structurale (IPBS), CNRS, 205 route de Narbonne, F-31077 Toulouse, France and Université Paul Sabatier, Université de Toulouse, F-31077 Toulouse, France
| | - Michel Rossignol
- Plateforme Protéomique Génopole Toulouse Midi-Pyrénées, Institut de Pharmacologie et de Biologie Structurale (IPBS), CNRS, 205 route de Narbonne, F-31077 Toulouse, France and Université Paul Sabatier, Université de Toulouse, F-31077 Toulouse, France
| | - David Wendehenne
- UMR INRA 1088/CNRS 5184/Université de Bourgogne Plante-Microbe-Environnement, 17 Rue Sully, BP 86510, 21065 Dijon cedex, France
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23
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Dieni CA, Storey KB. Regulation of glucose-6-phosphate dehydrogenase by reversible phosphorylation in liver of a freeze tolerant frog. J Comp Physiol B 2010; 180:1133-42. [DOI: 10.1007/s00360-010-0487-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Revised: 05/17/2010] [Accepted: 05/22/2010] [Indexed: 11/29/2022]
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24
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Emre Y, Nübel T. Uncoupling protein UCP2: When mitochondrial activity meets immunity. FEBS Lett 2010; 584:1437-42. [DOI: 10.1016/j.febslet.2010.03.014] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2009] [Revised: 02/20/2010] [Accepted: 03/10/2010] [Indexed: 11/26/2022]
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25
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Effects of glutamine on the nuclear factor-kappaB signaling pathway of murine peritoneal macrophages. Amino Acids 2010; 39:435-41. [DOI: 10.1007/s00726-009-0459-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Accepted: 12/20/2009] [Indexed: 12/15/2022]
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26
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Robinson MA, Turtle SW, Otto CM, Koch CJ. pO(2)-dependent NO production determines OPPC activity in macrophages. Free Radic Biol Med 2010; 48:189-95. [PMID: 19822207 PMCID: PMC4159751 DOI: 10.1016/j.freeradbiomed.2009.10.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Revised: 09/28/2009] [Accepted: 10/06/2009] [Indexed: 01/01/2023]
Abstract
Stimulated macrophages produce nitric oxide (NO) via inducible nitric oxide synthase (iNOS) using molecular O(2), L-arginine, and NADPH. Exposure of macrophages to hypoxia decreases NO production within seconds, suggesting substrate limitation as the mechanism. Conflicting data exist regarding the effect of pO(2) on NADPH production via the oxidative pentose phosphate cycle (OPPC). Therefore, the present studies were developed to determine whether NADPH could be limiting for NO production under hypoxia. Production of NO metabolites (NOx) and OPPC activity by RAW 264.7 cells was significantly increased by stimulation with lipopolysaccharide (LPS) and interferon gamma (IFNgamma) at pO(2) ranging from 0.07 to 50%. OPPC activity correlated linearly with NOx production at pO(2)>0.13%. Increased OPPC activity by stimulated RAW 264.7 cells was significantly reduced by 1400 W, an iNOS inhibitor. OPPC activity was significantly increased by concomitant treatment of stimulated RAW 264.7 cells with chemical oxidants such as hydroxyethyldisulfide or pimonidazole, at 0.07 and 50% O(2), without decreasing NOx production. These results are the first to investigate the effect of pO(2) on the relationship between NO production and OPPC activity, and to rule out limitations in OPPC activity as a mechanism by which NO production is decreased under hypoxia.
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Affiliation(s)
- Mary A. Robinson
- Department of Radiation Oncology, School of Medicine, University of Pennsylvania Philadelphia PA 19104
| | - Stephen W. Turtle
- Department of Radiation Oncology, School of Medicine, University of Pennsylvania Philadelphia PA 19104
| | - Cynthia M. Otto
- Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania Philadelphia PA 19104
- Center for Sleep and Respiratory Neurobiology, University of Pennsylvania Philadelphia, PA 19104
| | - Cameron J. Koch
- Department of Radiation Oncology, School of Medicine, University of Pennsylvania Philadelphia PA 19104
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27
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Busque SM, Wagner CA. Potassium restriction, high protein intake, and metabolic acidosis increase expression of the glutamine transporter SNAT3 (Slc38a3) in mouse kidney. Am J Physiol Renal Physiol 2009; 297:F440-50. [PMID: 19458124 DOI: 10.1152/ajprenal.90318.2008] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Kidneys produce ammonium to buffer and excrete acids through metabolism of glutamine. Expression of the glutamine transporter Slc38a3 (SNAT3) increases in kidney during metabolic acidosis (MA), suggesting a role during ammoniagenesis. Potassium depletion and high dietary protein intake are known to elevate renal ammonium excretion. In this study, we examined SNAT3, phosphate-dependent glutaminase (PDG), and phosphoenolpyruvate carboxykinase (PEPCK) regulation during a control (0.36%) or low-K(+) (0.02%) diet for 7 or 14 days or a control (20%) or high-protein (50%) diet for 7 days. MA was induced in control and low-K(+) groups by addition of NH(4)Cl. Urinary ammonium excretion increased during MA, after 14-day K(+) restriction alone, and during high protein intake. SNAT3, PDG, and PEPCK mRNA abundance were elevated during MA and after 14-day K(+) restriction but not during high protein intake. SNAT3 protein abundance was enhanced during MA (both control and low K(+)), after 14-day low-K(+) treatment alone, and during high protein intake. Seven-day dietary K(+) depletion alone had no effect. Immunohistochemistry showed SNAT3 staining in earlier parts of the proximal tubule during 14-day K(+) restriction with and without NH(4)Cl treatment and during high protein intake. In summary, SNAT3, PDG, and PEPCK mRNA expression were congruent with urinary ammonium excretion during MA. Chronic dietary K(+) restriction, high protein intake, and MA enhance ammoniagenesis, an effect that may involve enhanced SNAT3 mRNA and protein expression. Our data suggest that SNAT3 plays an important role as the glutamine uptake mechanism in ammoniagenesis under these conditions.
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Affiliation(s)
- Stephanie M Busque
- Institute of Physiology, Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
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28
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Dahan J, Pichereaux C, Rossignol M, Blanc S, Wendehenne D, Pugin A, Bourque S. Activation of a nuclear-localized SIPK in tobacco cells challenged by cryptogein, an elicitor of plant defence reactions. Biochem J 2009; 418:191-200. [PMID: 18925873 DOI: 10.1042/bj20081465] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
When a plant cell is challenged by a well-defined stimulus, complex signal transduction pathways are activated to promote the modulation of specific sets of genes and eventually to develop adaptive responses. In this context, protein phosphorylation plays a fundamental role through the activation of multiple protein kinase families. Although the involvement of protein kinases at the plasma membrane and cytosolic levels are now well-documented, their nuclear counterparts are still poorly investigated. In the field of plant defence reactions, no known study has yet reported the activation of a nuclear protein kinase and/or its nuclear activity in plant cells, although some protein kinases, e.g. MAPK (mitogen-activated protein kinase), are known to be translocated into the nucleus. In the present study, we investigated the ability of cryptogein, a proteinaceous elicitor of tobacco defence reactions, to induce different nuclear protein kinase activities. We found that at least four nuclear protein kinases are activated in response to cryptogein treatment in a time-dependent manner, some of them exhibiting Ca(2+)-dependent activity. The present study focused on one 47 kDa protein kinase with a Ca(2+)-independent activity, closely related to the MAPK family. After purification and microsequencing, this protein kinase was formally identified as SIPK (salicyclic acid-induced protein kinase), a biotic and abiotic stress-activated MAPK of tobacco. We also showed that cytosolic activation of SIPK is not sufficient to promote a nuclear SIPK activity, the latter being correlated with cell death. In that way, the present study provides evidence of a functional nuclear MAPK activity involved in response to an elicitor treatment.
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Affiliation(s)
- Jennifer Dahan
- UMR INRA 1088/CNRS 5184/Université de Bourgogne Plante-Microbe-Environnement, 17 Rue Sully, BP 86510, 21065 Dijon cédex, France
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Xu J, Han J, Long YS, Lock J, Weir GC, Epstein PN, Liu YQ. Malic enzyme is present in mouse islets and modulates insulin secretion. Diabetologia 2008; 51:2281-9. [PMID: 18802677 PMCID: PMC2777632 DOI: 10.1007/s00125-008-1155-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Accepted: 08/18/2008] [Indexed: 11/29/2022]
Abstract
AIMS/HYPOTHESIS The pyruvate-malate shuttle is a metabolic cycle in pancreatic beta cells and is important for beta cell function. Cytosolic malic enzyme (ME) carries out an essential step in the shuttle by converting malate to pyruvate and generating NADPH. In rat islets the pyruvate-malate shuttle may regulate insulin secretion and it has been shown to play a critical role in adaptation to obesity and insulin resistance. However, ME has not been demonstrated in mouse islets and three reports indicate that mouse islets contain no ME activity. If mouse islets lack ME, rat and mouse islets must regulate insulin secretion by different mechanisms. METHODS We measured ME activity by a fluorometric enzymatic assay and Me mRNA by real-time PCR. ME activity was also measured in streptozotocin-treated mouse islets. FACS-purified beta cells were obtained from MIP-GFP mouse islets, agouti-L obese mouse islets and mouse beta cell line MIN-6. Insulin secretion and NADPH/NADP(+) ratios were measured in Me siRNA-treated beta cells. RESULTS ME activity and Me mRNA were present in C57BL/6 mouse islets. ME activity was reduced in streptozotocin-treated mouse islets. ME activity was also measurable in FACS-purified mouse beta cells. In addition, ME activity was significantly increased in obese agouti-L mouse islets and the mouse MIN-6 cell line. Me siRNA inhibited ME activity and reduced glucose-stimulated insulin secretion and also inhibited NADPH products. CONCLUSIONS/INTERPRETATION Mouse islets contain ME, which plays a significant role in regulating insulin secretion.
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Affiliation(s)
- Jianxiang Xu
- Kosair Children's Hospital Research Institute, Department of Pediatrics, University of Louisville School of Medicine, Louisville, KY, 40202
| | - Junying Han
- Kosair Children's Hospital Research Institute, Department of Pediatrics, University of Louisville School of Medicine, Louisville, KY, 40202
- The Research Institute for Children, Children’s Hospital; Department of Pediatrics, LSUHSC, New Orleans, LA 70118
| | - Yun Shi Long
- Kosair Children's Hospital Research Institute, Department of Pediatrics, University of Louisville School of Medicine, Louisville, KY, 40202
| | - Jennifer Lock
- Joslin Diabetes Center, One Joslin Place, Harvard Medical School, Boston, MA, 02215
| | - Gordon C. Weir
- Joslin Diabetes Center, One Joslin Place, Harvard Medical School, Boston, MA, 02215
| | - Paul N. Epstein
- Kosair Children's Hospital Research Institute, Department of Pediatrics, University of Louisville School of Medicine, Louisville, KY, 40202
| | - Ye Qi Liu
- Kosair Children's Hospital Research Institute, Department of Pediatrics, University of Louisville School of Medicine, Louisville, KY, 40202
- The Research Institute for Children, Children’s Hospital; Department of Pediatrics, LSUHSC, New Orleans, LA 70118
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30
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Mouillet-Richard S, Nishida N, Pradines E, Laude H, Schneider B, Féraudet C, Grassi J, Launay JM, Lehmann S, Kellermann O. Prions impair bioaminergic functions through serotonin- or catecholamine-derived neurotoxins in neuronal cells. J Biol Chem 2008; 283:23782-90. [PMID: 18617522 DOI: 10.1074/jbc.m802433200] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The conversion of the cellular prion protein, PrP(C), to an abnormal isoform, PrP(Sc), is a central event leading to neurodegeneration in prion diseases. Deciphering the molecular and cellular changes imparted by PrP(Sc) accumulation remains an arduous task due to the small number of cell lines supporting prion replication. Here we introduce the 1C11 cell line as a new in vitro model to investigate prion pathogenesis. This cell line is a committed neuroectodermal progenitor able to differentiate into fully functional serotonergic or catecholaminergic neurons. 1C11 cells, which naturally express PrP(C) from the undifferentiated state, can be chronically infected with various prion strains. Prion infection does not promote any noticeable phenotypic change in the progenitor cells nor prevent the onset of the serotonergic and catecholaminergic differentiation programs. Pathogenic prions, however, deviate the overall neurotransmitter-metabolism in both pathways by decreasing bioamine synthesis, storage, and transport, and enhancing catabolism. Noteworthy, oxidized derivatives of both serotonin and catecholamines are selectively detected in the differentiated progenies of infected cells and contribute to irreversible impairment in bioamine synthesis. Finally, the level of PrP(Sc) accumulation, that of infectivity, and the extent of all prion-induced changes in infected cells appear to be correlated. The report of such specific effects of infection on neuronal functions provides a foundation for dissecting the events underlying loss of neuronal homeostasis in prion diseases.
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Affiliation(s)
- Sophie Mouillet-Richard
- Différenciation Cellulaire et prions, CNRS FRE 2937, Institut Pasteur, INSERM U747, 7 rue Guy Môquet, Villejuif, France.
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31
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Rogero MM, Tirapegui J, Vinolo MAR, Borges MC, de Castro IA, Pires ISDO, Borelli P. Dietary glutamine supplementation increases the activity of peritoneal macrophages and hemopoiesis in early-weaned mice inoculated with Mycobacterium bovis bacillus Calmette-Guérin. J Nutr 2008; 138:1343-8. [PMID: 18567758 DOI: 10.1093/jn/138.7.1343] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Infants who are breast-fed have been shown to have a lower incidence of certain infectious diseases compared with formula-fed infants. Glutamine is one of the most abundant amino acids found in maternal milk and it is essential for the function of immune system cells such as macrophages. The purpose of this study was to investigate the effect of glutamine supplementation on the function of peritoneal macrophages and on hemopoiesis in early-weaned mice inoculated with Mycobacterium bovis bacillus Calmette-Guérin (BCG). Mice were weaned at 14 d of age and distributed to 2 groups and fed either a glutamine-free diet (n = 16) or a glutamine-supplemented diet (+Gln) (n = 16). Both diets were isonitrogenous (with addition of a mixture of nonessential amino acids) and isocaloric. At d 21, 2 subgroups of mice (n = 16) were intraperitoneally injected with BCG and all mice were killed at d 28. Plasma, muscle and liver glutamine concentrations and muscle glutamine synthetase activity were not affected by diet or inoculation with BCG. The +Gln diet led to increased leukocyte and lymphocyte counts in the peripheral blood (P < 0.05) and granulocyte and lymphocyte counts in the bone marrow and spleen (P < 0.05). The +Gln diet increased spreading and adhesion capacities, hydrogen peroxide, nitric oxide, and tumor necrosis factor-alpha (TNFalpha) syntheses and the phagocytic and fungicidal activity of peritoneal macrophages (P < 0.05). The interaction between the +Gln diet and BCG inoculation increased the area under the curve of interleukin (IL)-1beta and TNFalpha syntheses (P < 0.05). In conclusion, the intake of glutamine increases the function of peritoneal macrophages and hemopoiesis in early-weaned and BCG-inoculated mice. These data have important implications for the design of breast milk substitutes for human infants.
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Affiliation(s)
- Marcelo Macedo Rogero
- Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil.
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32
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Bacurau AVN, Belmonte MA, Navarro F, Moraes MR, Pontes FL, Pesquero JL, Araújo RC, Bacurau RFP. Effect of a high-intensity exercise training on the metabolism and function of macrophages and lymphocytes of walker 256 tumor bearing rats. Exp Biol Med (Maywood) 2008; 232:1289-99. [PMID: 17959841 DOI: 10.3181/0704-rm-93] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Epidemiologic studies suggest that moderately intense training promotes augmented immune function, whereas strenuous exercise can cause immunosupression. Because the combat of cancer requires high immune function, high-intensity exercise could negatively affect the host organism; however, despite the epidemiologic data, there is a lack of experimental evidence to show that high-intensity training is harmful to the immune system. Therefore, we tested the influence of high-intensity treadmill training (10 weeks, 5 days/week, 30 mins/day, 85% VO(2)max) on immune system function and tumor development in Walker 256 tumor-bearing Wistar rats. The metabolism of glucose and glutamine in lymphocytes and macrophages was assessed, in addition to some functional parameters such as hydrogen peroxide production, phagocytosis, and lymphocyte proliferative responses. The metabolism of Walker 256 cells was also investigated. Results demonstrated that high-intensity training increased the life span of tumor-bearing rats, promoted a reduction in tumor mass, and prevented indicators of cachexia. Several changes, such as a reduction in body weight and food intake and activation of glutamine metabolism in macrophages and lymphocytes induced by the presence of Walker 256 tumor, were prevented by high intensity training. The reduction in tumor growth was associated with an impairment of tumor cell glucose and glutamine metabolism. These data suggest that high-intensity exercise training may be a viable strategy against tumors.
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33
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Dammer EB, Sewer MB. Phosphorylation of CtBP1 by cAMP-dependent protein kinase modulates induction of CYP17 by stimulating partnering of CtBP1 and 2. J Biol Chem 2008; 283:6925-34. [PMID: 18184656 DOI: 10.1074/jbc.m708432200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the human adrenal cortex, the peptide hormone adrenocorticotropin (ACTH) directs cortisol and adrenal androgen biosynthesis by activating a cAMP/cAMP-dependent protein kinase (PKA) pathway. Carboxyl-terminal binding protein 1 (CtBP1) is a corepressor that regulates transcription of the CYP17 gene by periodically interacting with steroidogenic factor-1 in response to ACTH signaling. Given that CtBP1 function is regulated by NADH binding, we hypothesized that ACTH-stimulated changes in cellular pyridine nucleotide concentrations modulate the ability of CtBP1 to repress CYP17 transcription. Further, we postulated that PKA evokes changes in the phosphorylation status of CtBP1 that control the ability of the protein to bind to steroidogenic factor-1 and the coactivator GCN5 (general control nonderepressed 5) and repress CYP17 gene expression. We show that ACTH alters pyridine nucleotide redox state and identify amino acid residues in CtBP1 that are targeted by PKA and PAK6. Both ACTH/cAMP signaling and NADH/NAD+ ratio stimulate nuclear-cytoplasmic oscillation of both CtBP proteins. We provide evidence that PKA 1) induces metabolic changes in the adrenal cortex and 2) phosphorylates CtBP proteins, particularly CtBP1 at T144, resulting in CtBP protein partnering and ACTH-dependent CYP17 transcription.
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Affiliation(s)
- Eric B Dammer
- School of Biology and Parker H Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332-0230, USA
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34
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Sudnikovich EJ, Maksimchik YZ, Zabrodskaya SV, Kubyshin VL, Lapshina EA, Bryszewska M, Reiter RJ, Zavodnik IB. Melatonin attenuates metabolic disorders due to streptozotocin-induced diabetes in rats. Eur J Pharmacol 2007; 569:180-7. [PMID: 17597602 DOI: 10.1016/j.ejphar.2007.05.018] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2007] [Revised: 05/10/2007] [Accepted: 05/15/2007] [Indexed: 12/31/2022]
Abstract
Enhanced oxidative stress and impairments in nitric oxide synthesis and bioavailability are of considerable importance in the pathogenesis of diabetic vascular diseases. The aim of the present work was to evaluate the metabolic effects of pharmacological doses of the melatonin, a known antioxidant, on streptozotocin-induced diabetic damage in rats. We investigated the indolamine's influence on the cellular redox-balance, nitric oxide (NO) level, and the activities of antioxidative defence enzymes, as well as the activities of enzymes involved in phase II detoxication and NADPH-generating pentose phosphate pathway. Blood glucose, glycated hemoglobin, bilirubin, as well as plasma alanine aminotransferase activities increased and body weight was reduced in rats with streptozotocin-induced (60 mg/kg, i.p.) diabetes (25 days). The NO level was markedly increased in diabetic plasma (by 50%) and aortic tissue (by 30%). The hyperglycemia resulted in reduced activities of glutathione peroxidase (by 25%), catalase (by 20%), glucose-6-phosphate dehydrogenase (by 55%) and transketolase (by 40%) in liver tissue of diabetic animals. Melatonin treatment (10 mg/kg, 18 days) did not influence the level of hyperglycemia or glycated hemoglobin and it had little effect on the activities of antioxidative enzymes. However, melatonin markedly reversed the activities of glucose-6-phosphate dehydrogenase and transketolase in liver tissue of diabetic rats. The most pronounced effect of the melatonin administration was the prevention of an increase in nitric oxide levels in blood plasma and aortic tissue during diabetes. In in vitro experiments, nitrosomelatonin formation in the presence of nitrosodonors was observed. This implies that melatonin might operate as an NO scavenger and carrier. Thus, melatonin treatment may have some beneficial effects in controlling diabetic vascular complications.
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Affiliation(s)
- Elena Ju Sudnikovich
- State Research and Innovation Center, Institute for Pharmacology and Biochemistry of the National Academy of Sciences of Belarus, BLK-50, 230017 Grodno, Belarus
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35
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Lapshina EA, Sudnikovich EJ, Maksimchik JZ, Zabrodskaya SV, Zavodnik LB, Kubyshin VL, Nocun M, Kazmierczak P, Dobaczewski M, Watala C, Zavodnik IB. Antioxidative enzyme and glutathione S-transferase activities in diabetic rats exposed to long-term ASA treatment. Life Sci 2006; 79:1804-11. [PMID: 16815474 DOI: 10.1016/j.lfs.2006.06.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2005] [Revised: 05/21/2006] [Accepted: 06/09/2006] [Indexed: 11/18/2022]
Abstract
Low-dose acetylsalicylic acid (ASA) treatment is a standard therapeutic approach in diabetes mellitus for prevention of long-term vascular complications. The aim of the present work was to investigate the effect of long-term ASA administration in experimental diabetes on activities of some liver enzymes: glutathione peroxidase (GSHPx), catalase, glucose-6-phosphate dehydrogenase (G6PDH) and glutathione S-transferase (GST). Blood glucose, glycated hemoglobin, as well as plasma ALT and AST activities increased in rats with streptozotocin-induced experimental diabetes. The long-term hyperglycemia resulted in decreased activities of GSHPx (by 26%), catalase (by 34%), GST (by 38%) and G6PDH (by 27%) in diabetic animals. We did not observe increased accumulation of membrane lipid peroxidation products or altered levels of reduced glutathione in livers. The linear correlation between blood glucose and glycated hemoglobin in diabetic animals was distorted upon ASA treatment, which was likely due to a chemical competition between nonenzymatic protein glycosylation and protein acetylation. The long-term ASA administration partially reversed the decrease in GSHPx activity, but did not influence the activities of catalase and GST in diabetic rats. Otherwise, some decrease in these parameters was noted in ASA-treated nondiabetic animals. Increased ASA-induced G6PDH activity was recorded in both diabetic and nondiabetic rats. While both glycation due to diabetic hyperglycemia and ASA-mediated acetylation had very similar effects on the activities of all studied enzymes but G6PDH, we conclude that non-enzymatic modification by either glucose or ASA may be a common mechanism of the observed convergence.
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Affiliation(s)
- E A Lapshina
- Institute of Biochemistry, National Academy of Sciences of Belarus, BLK-50, Grodno, Belarus
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36
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Moinard C. Immunomodulation par les nutriments. NUTR CLIN METAB 2006. [DOI: 10.1016/j.nupar.2006.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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37
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Kanno Y, Levi BZ, Tamura T, Ozato K. Immune cell-specific amplification of interferon signaling by the IRF-4/8-PU.1 complex. J Interferon Cytokine Res 2006; 25:770-9. [PMID: 16375605 DOI: 10.1089/jir.2005.25.770] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Both type I interferon (IFN-alpha/beta) and type II IFN (IFN-gamma) exert many functions that are restricted to immune cells. Thus, they play critical roles in innate and adaptive immunity. IFN regulatory factor-4 (IRF-4) and IRF-8 (formerly PU.1 interaction partner [Pip] and IFN consensus sequence binding domain [ICSBP], respectively) are immune cell-specific members of the IRF family that regulate the development of myeloid, lymphoid, and dendritic cells. They form a heterodimeric complex with another immune cell-specific transcription factor PU.1-Spi-1 and regulate transcription of genes in the immune system. This review describes the role of the IRF-8-PU.1 complex in modulating IFN signaling in an immune cell-specific manner. Our studies revealed that some but not all IFN-gamma-inducible genes carry an IFN-gamma activation site (GAS) element that contains a binding site for the IRF- 8-PU.1 complex. The IRF-8-PU.1 complex can take part in GAS-mediated transcription and amplify expression of IFN-gamma-responsive genes initiated by Stat1 in macrophages. Similarly, some but not all IFN-alpha/beta-responsive genes are shown to carry an IFN-stimulated response element (ISRE) that contains an IRF-8-PU.1 binding site. The participation of IRF-8-PU.1 in ISRE-mediated transcription results in the augmentation of IFN-stimulated gene factor 3 (ISGF3)-induced transcription in macrophages. Thus, GAS and ISRE elements, classically defined as universal IFN-alpha/beta and IFN-gamma response sequences, are not the same, and some harbor an embedded motif for IRF- 8-PU.1 binding that functions only in immune cells. Accordingly, the IRF-8-PU.1complex provides secondary IFN signaling pathways unique to the immune system. Collectively, the contribution of IRF-8 and PU.1 to IFN-regulated gene expression may in part account for immune cell-specific functions of IFNs.
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Affiliation(s)
- Yuka Kanno
- Molecular Immunology and Inflammation Branch, National Institute of Arthritis, Muscuolskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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38
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Silveira EMS, Rodrigues MF, Krause MS, Vianna DR, Almeida BS, Rossato JS, Oliveira LP, Curi R, de Bittencourt PIH. Acute exercise stimulates macrophage function: possible role of NF-κB pathways. Cell Biochem Funct 2006; 25:63-73. [PMID: 16906627 DOI: 10.1002/cbf.1365] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Moderate physical activity when performed on a regular basis presents a number of benefits to the whole organism, especially regarding immune system function, such as augmenting resistance to infections and to cancer growth. Although glutamine production by active muscle cells as well as neuroendocrine alterations mediated by the chronic adaptation to exercise may play a role, the entire mechanism by which exercise makes the immune system aware of challenges remains mostly uncovered. This is particularly true for the effects of an acute exercise session on immune function. In this work, circulating monocytes/macrophages from sedentary rats submitted to an acute (1 h) swimming session were tested for the ability of phagocytosing zymosan particles, phorbol myristate acetate (PMA)-induced hydrogen peroxide production, nitric oxide (NO) release (assessed by nitrate and nitrite production) and the expression of NO synthases (NOS-1, NOS-2 and NOS-3). The results showed that an exercise bout induced a 2.4-fold rise in macrophage phagocytic capacity (p = 0.0041), a 9.6-fold elevation in PMA-induced hydrogen peroxide release into the incubation media (1-h, p = 0.0022) and a 95.5%-augmentation in nitrite basal production (1-h incubation; p = 0.0220), which was associated with a marked expression of NOS-2 (the inducible NOS isoform; p = 0.0319), but not in other NOS gene products. Although NOS-2 expression is nuclear factor-kappaB (NF-kappaB)-dependent, no systemic oxidative stress was found, as inferred from the data of plasma TBARS and glutathione disulphide (GSSG) to glutathione (GSH) ratio in circulating blood erythrocytes which remained constant after the acute exercise. Also, no stressful situation seemed to be faced by monocytes/macrophages, since the expression of the 70-kDa heat shock protein (HSP70) remained unchanged. We conclude that NF-kappaB-dependent induction of NOS-2 and macrophage activation must be related to local factor(s) produced in the surroundings of monocytes/macrophages.
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Affiliation(s)
- Elza M S Silveira
- Department of Physiology, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
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Ramnanan CJ, Storey KB. Glucose-6-phosphate dehydrogenase regulation during hypometabolism. Biochem Biophys Res Commun 2005; 339:7-16. [PMID: 16256936 DOI: 10.1016/j.bbrc.2005.10.036] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2005] [Accepted: 10/08/2005] [Indexed: 11/27/2022]
Abstract
Glucose-6-phosphate dehydrogenase (G6PDH) from hepatopancreas of the land snail, Otala lactea, shows distinct changes in properties between active and estivating (dormant) states, providing the first evidence of pentose phosphate cycle regulation during hypometabolism. Compared with active snails, G6PDH Vmax increased by 50%, Km for glucose-6-phosphate decreased by 50%, Ka Mg x citrate decreased by 35%, and activation energy (from Arrhenius plots) decreased by 35% during estivation. DEAE-Sephadex chromatography separated two peaks of activity and in vitro incubations stimulating protein kinases or phosphatases showed that peak I (low phosphate) G6PDH was higher in active snails (57% of activity) whereas peak II (high phosphate) G6PDH dominated during estivation (71% of total). Kinetic properties of peaks I and II forms mirrored the enzyme from active and estivated states, respectively. Peak II G6PDH also showed reduced sensitivity to urea inhibition of activity and greater stability to thermolysin protease treatment. The interconversion of G6PDH between active and estivating forms was linked to protein kinase G and protein phosphatase 1. Estivation-induced phosphorylation of G6PDH may enhance relative carbon flow through the pentose phosphate cycle, compared with glycolysis, to help maintain NADPH production for use in antioxidant defense.
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Affiliation(s)
- Christopher J Ramnanan
- Institute of Biochemistry and Department of Biology, College of Natural Sciences, Carleton University, 1125 Colonel By Drive, Ottawa, Ont., Canada K1S 5B6
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40
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Abstract
To propose a new pathogenesis called Radical Induction to explain the genesis and progression of ulcerative colitis (UC). UC is an inflammatory bowel disease. Colonic inflammation in UC is mediated by a buildup of white blood cells (WBCs) within the colonic mucosal lining; however, to date there is no answer for why WBCs initially enter the colonic mucosa to begin with. A new pathogenesis termed “Radical Induction Theory” is proposed to explain this and states that excess un-neutralized hydrogen peroxide, produced within colonic epithelial cells as a result of aberrant cellular metabolism, diffuses through cell membranes to the extracellular space where it is converted to the highly damaging hydroxyl radical resulting in oxidative damage to structures comprising the colonic epithelial barrier. Once damaged, the barrier is unable to exclude highly immunogenic fecal bacterial antigens from invading the normally sterile submucosa. This antigenic exposure provokes an initial immune response of WBC infiltration into the colonic mucosa. Once present in the mucosa, WBCs are stimulated to secrete toxins by direct exposure to fecal bacteria leading to mucosal ulceration and bloody diarrhea characteristic of this disease.
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41
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Blanc MC, Moinard C, Béziel A, Darquy S, Cynober L, De Bandt JP. Arginine and glutamine availability and macrophage functions in the obese insulin-resistant Zucker rat. J Cell Physiol 2005; 202:153-9. [PMID: 15389544 DOI: 10.1002/jcp.20092] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Increased susceptibility to infections in obese patients may be related to decreased availability of arginine and glutamine, which may affect immune cell functions. Our aim was to evaluate the in vitro effects of these amino acids on the function of macrophages from obese insulin-resistant Zucker rats. Macrophages, isolated from male Zucker obese or lean rats by peritoneal lavage, were incubated in Dulbecco's modified Eagle medium (DMEM) without arginine or glutamine. Arginine or glutamine was added to the medium at increasing final concentrations (0, 0.25, 0.5, 1 or 2 mM). After stimulation by lipopolysaccharide (LPS) from E. coli (40 microg/ml), productions of tumour necrosis factor alpha (TNFalpha) and of nitric oxide (NO) were measured after 3 or 48 h incubation, respectively. NO production, lower in macrophages from obese rats, decreased in macrophages from lean rats (0 mM: 2,423 +/- 1,174 vs. 2 mM: 198 +/- 31 microM/mg protein/24 h; P < 0.05), but not in those from obese rats, when glutamine was added. TNFalpha production, lower in macrophages from obese rats, was inversely correlated with glutamine concentration. In the presence of arginine, NO production was constantly higher in macrophages from obese rats. It peaked at 0.5 mM arginine and decreased thereafter in both groups. TNFalpha production in macrophages from lean rats was unaffected by arginine, but decreased in macrophages from obese rats (0 mM: 1920 +/- 450 vs. 2 mM: 810 +/- 90 microM/mg protein/3 h; P < 0.05). These results suggest that abnormalities in cell signalling or in arginine and glutamine metabolism in macrophages of obese rats, resulting in decreased TNFalpha production and increased NO release, may contribute to increased susceptibility to infection in insulin-resistant states.
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Affiliation(s)
- Marie-Céline Blanc
- Laboratoire de Biologie de la Nutrition, Faculté des Sciences Pharmaceutiques et Biologiques, Université Paris 5-René Descartes, Paris, France
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42
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Newsholme P, Procopio J, Lima MMR, Pithon-Curi TC, Curi R. Glutamine and glutamate--their central role in cell metabolism and function. Cell Biochem Funct 2003; 21:1-9. [PMID: 12579515 DOI: 10.1002/cbf.1003] [Citation(s) in RCA: 407] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Glucose is widely accepted as the primary nutrient for maintenance and promotion of cell function. However, we propose that the 5-carbon amino acids, glutamine and glutamate, should be considered to be equally important for maintenance and promotion of cell function. The functions of glutamine are many and include: substrate for protein synthesis, anabolic precursor for muscle growth, acid-base balance in the kidney, substrate for ureogenesis in the liver, substrate for hepatic and renal gluconeogenesis, an oxidative fuel for intestine and cells of the immune system, inter-organ nitrogen transport, precursor for neurotransmitter synthesis, precursor for nucleotide and nucleic acid synthesis and precursor for glutathione production. Many of these functions are connected to the formation of glutamate from glutamine. We propose that the unique properties regarding concentration and routes of metabolism of these amino acids allow them to be used for a diverse array of processes related to the specialized function of each of the glutamine utilizing cells. In this review we highlight the specialized aspects of glutamine/glutamate metabolism of different glutamine-utilizing cells and in each case relate key aspects of metabolism to cell function.
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Affiliation(s)
- Philip Newsholme
- Department of Biochemistry, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Ireland.
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43
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Abstract
RESUMO O estudo da relação entre o exercício e a resposta imune teve grande impulso a partir da metade da década de 70, tendo como principais áreas de interesse o estudo da infecção de vias aéreas superiores em atletas submetidos a grandes esforços, o exercício como modelo de estresse e a resposta do treinamento como resposta adaptativa frente a situações de estresse. A descrição da interação entre os sistemas imune e neuroendócrino foi de importância capital no desenvolvimento desses estudos. O exercício gerando um desvio da homeostase orgânica leva à reorganização das respostas de diversos sistemas, entre eles o sistema imune. É adequado dividir a resposta ao exercício em resposta aguda, resposta transitória ao estresse e resposta de adaptação crônica, na qual o treinamento capacita o organismo a lidar com o estímulo estressante de maneira mais adequada. Ambas as respostas afetam os diversos componentes do sistema imune, tanto a resposta inata em seu componente celular compreendendo neutrófilos, macrófagos e células natural killer, como em seu componente humoral, proteínas de fase aguda, sistema do complemento e enzimas, como o sistema imune adaptativo, em seu componente celular (linfócitos T e B), como no componente humoral (anticorpos e citocinas). Apesar das incorreções que cometemos quando das generalizações, podemos dizer que, de modo geral, o exercício de intensidade moderada, praticado com regularidade, melhora a capacidade de resposta do sistema imune, enquanto o exercício de alta intensidade praticado sob condições estressantes provoca um estado transitório de imunodepressão.
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Vernet P, Fulton N, Wallace C, Aitken RJ. Analysis of reactive oxygen species generating systems in rat epididymal spermatozoa. Biol Reprod 2001; 65:1102-13. [PMID: 11566731 DOI: 10.1095/biolreprod65.4.1102] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Epididymal sperm maturation culminates in the acquisition of functional competence by testicular spermatozoa. The expression of this functional state is dependent upon a redox-regulated, cAMP-mediated signal transduction cascade that controls the tyrosine phosphorylation status of the spermatozoa during capacitation. Analysis of superoxide anion (O2(-.)) generation by rat epididymal spermatozoa has revealed a two-component process involving electron leakage from the sperm mitochondria at complexes I and II and a plasma membrane NAD(P)H oxidoreductase. Following incubation in a glucose-, lactate-, and pyruvate-free medium (-GLP), O2(-.) generation was suppressed by 86% and 96% in caput and cauda spermatozoa, respectively. The addition of lactate, malate, or succinate to spermatozoa incubated in medium -GLP stimulated O2(-.) generation. This increase could be blocked by rotenone and oligomycin (R/O) in the presence of malate or lactate but not succinate. Stimulation with all three substrates, as well as spontaneous O2(-.) production in +GLP medium, was blocked by the flavoprotein inhibitor, diphenylene iodonium. Diphenylene iodonium, but not R/O, suppressed NAD(P)H-induced lucigenin-dependent chemiluminescence. This NAD(P)H-dependent enzyme resided in the sperm plasma membrane and its activity was regulated by zinc and uncharacterized cytosolic factors. Reverse transcription-polymerase chain reaction analysis indicated that the sperm NAD(P)H oxidoreductase complex is quite distinct from the equivalent leukocyte system.
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Affiliation(s)
- P Vernet
- MRC Reproductive Biology Unit, Edinburgh EH3 9ET, Scotland, UK
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45
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Newsholme P. Why is L-glutamine metabolism important to cells of the immune system in health, postinjury, surgery or infection? J Nutr 2001; 131:2515S-22S; discussion 2523S-4S. [PMID: 11533304 DOI: 10.1093/jn/131.9.2515s] [Citation(s) in RCA: 376] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Glutamine is normally considered to be a nonessential amino acid. However, recent studies have provided evidence that glutamine may become "conditionally essential" during inflammatory conditions such as infection and injury. It is now well documented that under appropriate conditions, glutamine is essential for cell proliferation, that it can act as a respiratory fuel and that it can enhance the function of stimulated immune cells. Studies thus far have determined the effect of extracellular glutamine concentration on lymphocyte proliferation and cytokine production, macrophage phagocytic plus secretory activities and neutrophil bacterial killing. Other cells of the immune system remain to be studied. The high rate of glutamine utilization and its importance to the function of lymphocytes, macrophages and neutrophils have raised the question "why glutamine?" because these cells have access to a variety of metabolic fuels both in vivo and in vitro. I have attempted to answer this question in this article. Additionally, knowledge of the rate of utilization and the pathway of metabolism of glutamine by cells of the immune system raises some intriguing questions concerning therapeutic manipulation of utilization of this amino acid such that the proliferative, phagocytic and secretory capacities of cells of the defense system may be beneficially altered. Evidence to support the hypothesis that glutamine is beneficially immunomodulatory in animal models of infection and trauma, as well as trauma in humans, is provided.
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Affiliation(s)
- P Newsholme
- Department of Biochemistry, Conway Institute for Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
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Zhang Z, Apse K, Pang J, Stanton RC. High glucose inhibits glucose-6-phosphate dehydrogenase via cAMP in aortic endothelial cells. J Biol Chem 2000; 275:40042-7. [PMID: 11007790 DOI: 10.1074/jbc.m007505200] [Citation(s) in RCA: 151] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Recent studies have shown that hyperglycemia is a principal cause of cellular damage in patients with diabetes mellitus. A major consequence of hyperglycemia is increased oxidative stress. Glucose-6-phosphate dehydrogenase (G6PD) plays an essential role in the regulation of oxidative stress by primarily regulating NADPH, the main intracellular reductant. In this paper we show that increased glucose (10-25 mm) caused inhibition of G6PD resulting in decreased NADPH levels in bovine aortic endothelial cells (BAEC). Inhibition was seen within 15 min. High glucose-induced inhibition of G6PD predisposed cells to cell death. High glucose via increased activity of adenylate cyclase also stimulated an increase in cAMP levels in BAEC. Agents that increased cAMP caused a decrease in G6PD activity. Inhibition of cAMP-dependent protein kinase A ameliorated the high glucose-induced inhibition of G6PD. Finally, high glucose stimulated phosphorylation of G6PD. These results suggest that, in BAEC, high glucose stimulated increased cAMP, which led to increased protein kinase A activity, phosphorylation of G6PD, and inhibition of G6PD activity. We conclude that these changes in G6PD activity play an important role in high glucose-induced cell damage/death.
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Affiliation(s)
- Z Zhang
- Renal Division and Department of Medicine, Joslin Diabetes Center, Beth Israel Deaconess Medical Center, and Harvard Medical School, Boston, Massachusetts 02215, USA
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Bacurau RF, Homem De Bittencourt PI, Newsholme P, Costa Rosa LF. Metabolic response of macrophages to injury promoted by the activated complement system. Cell Biochem Funct 1999; 17:175-82. [PMID: 10451538 DOI: 10.1002/(sici)1099-0844(199909)17:3<175::aid-cbf825>3.0.co;2-s] [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: 01/20/2023]
Abstract
In nucleated cells, the swelling promoted by a complement system (CS) attack is not enough to promote cell death, because unlike erythrocytes these cells are able to eliminate cytolytic complement channels from the plasma membrane, by processes that include endocytosis. Several studies have demonstrated that the resistance of nucleated cells to the injury promoted by the CS is related to the cellular metabolism. Despite this, to the present day, no study has clearly related cell survival capacity to injury by the CS to its energetic metabolic status. In macrophages, the challenge imposed by the CS provoked an increase in the total amount of glucose incorporated into fatty acids, including phospholipids and cholesterol; substrates for membrane synthesis. The inhibition of cholesterol synthesis promoted an increase of the cell death rate. These data support the importance of cholesterol metabolism for macrophage resistance to necrosis induced by the activated complement system.
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Affiliation(s)
- R F Bacurau
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, SP, Brazil
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48
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Seelaender MC, Kazantzis M, Costa Rosa LF. The effect of adrenaline and Walker-256 tumour-induced cachexia upon Kupffer cell metabolism. Cell Biochem Funct 1999; 17:151-6. [PMID: 10451535 DOI: 10.1002/(sici)1099-0844(199909)17:3<151::aid-cbf820>3.0.co;2-k] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Kupffer cells (KC), the liver macrophages, are able to produce PGE(2), which is involved in immune suppression and in the aggravation of cancer cachexia due to interference with lipid metabolism in the liver. Since tumour-bearing (TB) rats present high plasma epinephrine levels, and this hormone is able to affect macrophage metabolism and function, we have assessed the effect of epinephrine (5 nM) upon Kupffer cell PGE(2) production. Epinephrine induced increased production of PGE(2) both by control (3.5-fold) and TB rats (27 per cent) KC, an effect blocked by propranolol. Enhancement of cAMP content in the cells by addition of isoproterenol (0.1 microM) to the incubations, however, failed to induce the same response in the cells. Nevertheless, when phenylephrine (1 microM) was added to the incubation, a similar pattern of PGE(2) production to that observed for epinephrine was found for control and TB rat KC. We propose that the effect of epinephrine upon KC PGE(2) production is mediated by alpha-adrenergic receptors and that Ca(2+) is involved in the response, since increasing concentrations of the ion added to the incubation medium (0.25, 0.5 and 1.0 mM) enhanced the eicosanoid production, while EDTA abolished the response.
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Affiliation(s)
- M C Seelaender
- Department of Histology and Embryology, Institute of Biomedical Sciences, University of São Paulo, Brazil
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Tian WN, Braunstein LD, Apse K, Pang J, Rose M, Tian X, Stanton RC. Importance of glucose-6-phosphate dehydrogenase activity in cell death. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 276:C1121-31. [PMID: 10329961 DOI: 10.1152/ajpcell.1999.276.5.c1121] [Citation(s) in RCA: 175] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The intracellular redox potential plays an important role in cell survival. The principal intracellular reductant NADPH is mainly produced by the pentose phosphate pathway by glucose-6-phosphate dehydrogenase (G6PDH), the rate-limiting enzyme, and by 6-phosphogluconate dehydrogenase. Considering the importance of NADPH, we hypothesized that G6PDH plays a critical role in cell death. Our results show that 1) G6PDH inhibitors potentiated H2O2-induced cell death; 2) overexpression of G6PDH increased resistance to H2O2-induced cell death; 3) serum deprivation, a stimulator of cell death, was associated with decreased G6PDH activity and resulted in elevated reactive oxygen species (ROS); 4) additions of substrates for G6PDH to serum-deprived cells almost completely abrogated the serum deprivation-induced rise in ROS; 5) consequences of G6PDH inhibition included a significant increase in apoptosis, loss of protein thiols, and degradation of G6PDH; and 6) G6PDH inhibition caused changes in mitogen-activated protein kinase phosphorylation that were similar to the changes seen with H2O2. We conclude that G6PDH plays a critical role in cell death by affecting the redox potential.
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Affiliation(s)
- W N Tian
- Renal Division and Department of Medicine, Joslin Diabetes Center, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02115, USA
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50
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Abstract
The liver plays a central role in the establishment and maintenance of the cachectic state in rats bearing extra-hepatic tumours. Kupffer cells, which as macrophages, show a strong relationship between metabolism and function could be involved in the alterations observed in the disruption of many functions of the organ as a whole. To assess whether the metabolic/functional pattern of Kupffer cells was altered by cachexia we have investigated the utilization of glucose, glutamine and palmitate by the cells from tumour-bearing and control rats. We have found an enhanced utilization of the three substrates by the cells from tumour-bearing rats as compared with controls, which was related to greater energy production through the Krebs cycle and enhanced production of precursors for the synthesis of the many substances the cells secrete when activated. The use of palmitate as substrate was also augmented in these cells, in the opposition to the observation in stimulated peritoneal macrophages. The availability of palmitate however, was not associated with a reduction of glucose or glutamine consumption. The cycle of interconversion, free fatty acids/triacyglycerol in Kupffer cells from tumour-bearing rats was also found to be increased, as was hydrogen peroxide production. Taken together the results suggest an increased utilization of substrates for both energy production and for synthetic processes (e.g. NADPH for hydrogen peroxide production).
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Affiliation(s)
- L F Rosa
- Department of Histology and Emrbyology, University of São Paulo, Brazil.
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