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DeMichele E, Sosnowski O, Buret AG, Allain T. Regulatory Functions of Hypoxia in Host-Parasite Interactions: A Focus on Enteric, Tissue, and Blood Protozoa. Microorganisms 2023; 11:1598. [PMID: 37375100 PMCID: PMC10303274 DOI: 10.3390/microorganisms11061598] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 06/13/2023] [Accepted: 06/14/2023] [Indexed: 06/29/2023] Open
Abstract
Body tissues are subjected to various oxygenic gradients and fluctuations and hence can become transiently hypoxic. Hypoxia-inducible factor (HIF) is the master transcriptional regulator of the cellular hypoxic response and is capable of modulating cellular metabolism, immune responses, epithelial barrier integrity, and local microbiota. Recent reports have characterized the hypoxic response to various infections. However, little is known about the role of HIF activation in the context of protozoan parasitic infections. Growing evidence suggests that tissue and blood protozoa can activate HIF and subsequent HIF target genes in the host, helping or hindering their pathogenicity. In the gut, enteric protozoa are adapted to steep longitudinal and radial oxygen gradients to complete their life cycle, yet the role of HIF during these protozoan infections remains unclear. This review focuses on the hypoxic response to protozoa and its role in the pathophysiology of parasitic infections. We also discuss how hypoxia modulates host immune responses in the context of protozoan infections.
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Affiliation(s)
- Emily DeMichele
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada; (E.D.); (O.S.); (A.G.B.)
- Inflammation Research Network, University of Calgary, Calgary, AB T2N 1N4, Canada
- Host-Parasite Interactions, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Olivia Sosnowski
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada; (E.D.); (O.S.); (A.G.B.)
- Inflammation Research Network, University of Calgary, Calgary, AB T2N 1N4, Canada
- Host-Parasite Interactions, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Andre G. Buret
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada; (E.D.); (O.S.); (A.G.B.)
- Inflammation Research Network, University of Calgary, Calgary, AB T2N 1N4, Canada
- Host-Parasite Interactions, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Thibault Allain
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada; (E.D.); (O.S.); (A.G.B.)
- Inflammation Research Network, University of Calgary, Calgary, AB T2N 1N4, Canada
- Host-Parasite Interactions, University of Calgary, Calgary, AB T2N 1N4, Canada
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Yamasaki Y, Matsuura K, Sasaki D, Shimizu T. Assessment of human bioengineered cardiac tissue function in hypoxic and re-oxygenized environments to understand functional recovery in heart failure. Regen Ther 2021; 18:66-75. [PMID: 33869689 PMCID: PMC8044384 DOI: 10.1016/j.reth.2021.03.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 03/09/2021] [Accepted: 03/21/2021] [Indexed: 01/30/2023] Open
Abstract
Introduction Myocardial recovery is one of the targets for heart failure treatment. A non-negligible number of heart failure with reduced ejection fraction (EF) patients experience myocardial recovery through treatment. Although myocardial hypoxia has been reported to contribute to the progression of heart failure even in non-ischemic cardiomyopathy, the relationship between contractile recovery and re-oxygenation and its underlying mechanisms remain unclear. The present study investigated the effects of hypoxia/re-oxygenation on bioengineered cardiac cell sheets-tissue function and the underlying mechanisms. Methods Bioengineered cardiac cell sheets-tissue was fabricated with human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CM) using temperature-responsive culture dishes. Cardiac tissue functions in the following conditions were evaluated with a contractile force measurement system: continuous normoxia (20% O2) for 12 days; hypoxia (1% O2) for 4 days followed by normoxia (20% O2) for 8 days; or continuous hypoxia (1% O2) for 8 days. Cell number, sarcomere structure, ATP levels, mRNA expressions and Ca2+ transients of hiPSC-CM in those conditions were also assessed. Results Hypoxia (4 days) elicited progressive decreases in contractile force, maximum contraction velocity, maximum relaxation velocity, Ca2+ transient amplitude and ATP level, but sarcomere structure and cell number were not affected. Re-oxygenation (8 days) after hypoxia (4 days) was associated with progressive increases in contractile force, maximum contraction velocity and relaxation time to the similar extent levels of continuous normoxia group, while maximum relaxation velocity was still significantly low even after re-oxygenation. Ca2+ transient magnitude, cell number, sarcomere structure and ATP level after re-oxygenation were similar to those in the continuous normoxia group. Hypoxia/re-oxygenation up-regulated mRNA expression of PLN. Conclusions Hypoxia and re-oxygenation condition directly affected human bioengineered cardiac tissue function. Further understanding the molecular mechanisms of functional recovery of cardiac tissue after re-oxygenation might provide us the new insight on heart failure with recovered ejection fraction and preserved ejection fraction.
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Key Words
- ATP, adenosine triphosphate
- Cardiac cell sheet
- Contractile force
- DMEM, Dulbecco's Modified Eagle Medium
- EF, ejection fraction
- FBS, fetal bovine serum
- HFmrEF, heart failure with midrange EF
- HFpEF, heart failure with preserved EF
- HFrEF, heart failure with reduced EF
- Heart failure
- Human induced pluripotent stem cells
- Hypoxia
- NPPA, natriuretic peptide precursor A
- PLN, phospholamban
- Re-oxygenation
- SERCA, sarco/endoplasmic reticulum Ca2+ ATPase
- cTnT, cardiac troponin T
- hiPSC-CMs, human induced pluripotent stem cell-derived cardiomyocytes
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Affiliation(s)
- Yu Yamasaki
- Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, Tokyo, Japan
| | - Katsuhisa Matsuura
- Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, Tokyo, Japan
- Department of Cardiology, Tokyo Women's Medical University, Tokyo, Japan
- Corresponding author. Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan.
| | - Daisuke Sasaki
- Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, Tokyo, Japan
| | - Tatsuya Shimizu
- Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, Tokyo, Japan
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Datta Chaudhuri R, Banerjee D, Banik A, Sarkar S. Severity and duration of hypoxic stress differentially regulates HIF-1α-mediated cardiomyocyte apoptotic signaling milieu during myocardial infarction. Arch Biochem Biophys 2020; 690:108430. [PMID: 32473132 DOI: 10.1016/j.abb.2020.108430] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 04/30/2020] [Accepted: 05/21/2020] [Indexed: 01/04/2023]
Abstract
BACKGROUND The severity and duration of hypoxia is known to determine apoptotic fate in heart; however, its implication during myocardial infarction (MI) remains unaddressed. Therefore the aim of the study was to determine apoptotic regulation in cardiomyocytes under varied hypoxic intensity and duration and to unravel the role of HIF-1α in such modulation. METHODS Treatment of cardiomyocytes to varied hypoxic intensity and duration was carried out in vitro, which was mimicked in vivo by dose-dependent Isoproterenol hydrochloride treatment for varied time-points. Myocardium-targeted HIF-1α knockdown in vivo was performed to decipher its role in cardiomyocyte apoptosis under varied stress. Signaling intermediates were analyzed by RT-PCR, immunoblotting and co-immunoprecipitation. DCFDA-based ROS assay, Griess assay for NO release and biochemical assays for estimating caspase activity were performed. RESULTS Severe stress resulted in cardiomyocyte apoptosis in both shorter and longer time-points. Moderate stress, on the other hand, induced apoptosis only in the shorter time-point which was downregulated in the longer time-point. ROS activity was upregulated under severe hypoxic stress for both time-points and only in the early time-point under moderate hypoxia. Increased ROS accumulation activated ERK-1/2 which stabilized nuclear HIF-1α, promoting bnip3-mediated apoptosis. Stable HSP90-IRE-1 association in such cells caused elevated endoplasmic reticulum stress-related caspase-12 activity. Sustained moderate hypoxia caused decline in ROS activity, but upregulated NFκB-dependent NO generation. NO-stabilized HIF-1α was predominantly cytosolic, since low ROS levels downregulated ERK-1/2 activity, thereby suppressing bnip3 expression. Cytosolic HIF-1α in such cells sequestered HSP90 from IRE-1, downregulating caspase-12 activity due to proteasomal degradation of IRE-1. Accordingly, myocardium-specific in vivo silencing of HIF-1α was beneficial at both time-points under severe stress as also for lesser duration of moderate stress. However, silencing of HIF-1α aggravated apoptotic injury during sustained moderate stress. CONCLUSION ROS-mediated HIF-1α stabilization promotes cardiomyocyte apoptosis on one hand while NO-mediated stabilization of HIF-1α disrupts apoptosis depending upon the severity and duration of hypoxia. Therefore the outcome of modulation of cardiac HIF-1α activity is regulated by both the severity and duration of ischemic stress.
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Affiliation(s)
- Ratul Datta Chaudhuri
- Department of Zoology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata 700019, West Bengal, India.
| | - Durba Banerjee
- Department of Zoology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata 700019, West Bengal, India.
| | - Anirban Banik
- Department of Zoology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata 700019, West Bengal, India.
| | - Sagartirtha Sarkar
- Department of Zoology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata 700019, West Bengal, India.
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Zhang Q, Kong X, Yuan H, Guan H, Li Y, Niu Y. Mangiferin Improved Palmitate-Induced-Insulin Resistance by Promoting Free Fatty Acid Metabolism in HepG2 and C2C12 Cells via PPAR α: Mangiferin Improved Insulin Resistance. J Diabetes Res 2019; 2019:2052675. [PMID: 30809553 PMCID: PMC6369470 DOI: 10.1155/2019/2052675] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 09/29/2018] [Accepted: 10/23/2018] [Indexed: 01/10/2023] Open
Abstract
Elevated free fatty acid (FFA) is a key risk factor for insulin resistance (IR). Our previous studies found that mangiferin could decrease serum FFA levels in obese rats induced by a high-fat diet. Our research was to determine the effects and mechanism of mangiferin on improving IR by regulating FFA metabolism in HepG2 and C2C12 cells. The model was used to quantify PA-induced lipid accumulation in the two cell lines treated with various concentrations of mangiferin simultaneously for 24 h. We found that mangiferin significantly increased insulin-stimulated glucose uptake, via phosphorylation of protein kinase B (P-AKT), glucose transporter 2 (GLUT2), and glucose transporter 4 (GLUT4) protein expressions, and markedly decreased glucose content, respectively, in HepG2 and C2C12 cells induced by PA. Mangiferin significantly increased FFA uptake and decreased intracellular FFA and triglyceride (TG) accumulations. The activity of the peroxisome proliferator-activated receptor α (PPARα) protein and its downstream proteins involved in fatty acid translocase (CD36) and carnitine palmitoyltransferase 1 (CPT1) and the fatty acid β-oxidation rate corresponding to FFA metabolism were also markedly increased by mangiferin in HepG2 and C2C12 cells. Furthermore, the effects were reversed by siRNA-mediated knockdown of PPARα. Mangiferin ameliorated IR by increasing the consumption of glucose and promoting the FFA oxidation via the PPARα pathway in HepG2 and C2C12 cells.
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Affiliation(s)
- Qiao Zhang
- Department of Nutrition and Food Hygiene, Public Health College, Harbin Medical University, Harbin 150086, China
| | - Xiangju Kong
- Department of Gynaecology, First Affiliated Hospital of Harbin Medical University, Harbin 150000, China
| | - Hang Yuan
- Department of Nutrition and Food Hygiene, Public Health College, Harbin Medical University, Harbin 150086, China
| | - Hongjun Guan
- Public Health College, Mudanjiang Medical University, Mudanjiang 157011, China
| | - Ying Li
- Department of Nutrition and Food Hygiene, Public Health College, Harbin Medical University, Harbin 150086, China
| | - Yucun Niu
- Department of Nutrition and Food Hygiene, Public Health College, Harbin Medical University, Harbin 150086, China
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Abstract
In some organisms and cells, oxygen availability influences oxygen consumption. In this review, we examine this phenomenon of hypoxic hypometabolism (HH), discussing its features, mechanisms, and implications. Small mammals and other vertebrate species exhibit "oxyconformism," a downregulation of metabolic rate and body temperature during hypoxia which is sensed by the central nervous system. Smaller body mass and cooler ambient temperature contribute to a high metabolic rate in mammals. It is this hypermetabolic state that is suppressed by hypoxia leading to HH. Larger mammals including humans do not exhibit HH. Tissues and cells also exhibit reductions in respiration during hypoxia in vitro, even at oxygen levels ample for mitochondrial oxidative phosphorylation. The mechanisms of cellular HH involve intracellular oxygen sensors including hypoxia-inducible factors, AMP-activated protein kinase (AMPK), and mitochondrial reactive oxygen species (ROS) which downregulate mitochondrial activity and ATP utilization. HH has a profound impact on cardiovascular, respiratory, and metabolic physiology in rodents. Therefore, caution should be exercised when extrapolating the results of rodent hypoxia studies to human physiology.
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Abstract
Although it is generally believed that oxidative phosphorylation and adequate oxygenation are essential for life, human development occurs in a profoundly hypoxic environment and "normal" levels of oxygen during embryogenesis are even harmful. The ability of embryos not only to survive but also to thrive in such an environment is made possible by adaptations related to metabolic pathways. Similarly, cancerous cells are able not only to survive but also to grow and spread in environments that would typically be fatal for healthy adult cells. Many biological states, both normal and pathological, share underlying similarities related to metabolism, the electron transport chain, and reactive species. The purpose of Part I of this review is to review the similarities among embryogenesis, mammalian adaptions to hypoxia (primarily driven by hypoxia-inducible factor-1), ischemia-reperfusion injury (and its relationship with reactive oxygen species), hibernation, diving animals, cancer, and sepsis, with a particular focus on the common characteristics that allow cells and organisms to survive in these states.
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Affiliation(s)
- Robert H Thiele
- From the Department of Anesthesiology, University of Virginia, Charlottesville, VA
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Gozal E, Metz CJ, Dematteis M, Sachleben LR, Schurr A, Rane MJ. PKA activity exacerbates hypoxia-induced ROS formation and hypoxic injury in PC-12 cells. Toxicol Lett 2017; 279:107-114. [PMID: 28751209 DOI: 10.1016/j.toxlet.2017.07.895] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 07/22/2017] [Indexed: 10/19/2022]
Abstract
Hypoxia is a primary factor in many pathological conditions. Hypoxic cell death is commonly attributed to metabolic failure and oxidative injury. cAMP-dependent protein kinase A (PKA) is activated in hypoxia and regulates multiple enzymes of the mitochondrial electron transport chain, thus may be implicated in cellular energy depletion and hypoxia-induced cell death. Wild type (WT) PC-12 cells and PKA activity-deficient 123.7 PC-12 cells were exposed to 3, 6, 12 and 24h hypoxia (0.1% or 5% O2). Hypoxia, at 24h 0.1% O2, induced cell death and increased reactive oxygen species (ROS) in WT PC-12 cells. Despite lower ATP levels in normoxic 123.7 cells than in WT cells, hypoxia only decreased ATP levels in WT cells. However, menadione-induced oxidative stress similarly affected both cell types. While mitochondrial COX IV expression remained consistently higher in 123.7 cells, hypoxia decreased COX IV expression in both cell types. N-acetyl cysteine antioxidant treatment blocked hypoxia-induced WT cell death without preventing ATP depletion. Transient PKA catα expression in 123.7 cells partially restored hypoxia-induced ROS but did not alter ATP levels or COX IV expression. We conclude that PKA signaling contributes to hypoxic injury, by regulating oxidative stress rather than by depleting ATP levels. Therapeutic strategies targeting PKA signaling may improve cellular adaptation and recovery in hypoxic pathologies.
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Affiliation(s)
- Evelyne Gozal
- Department of Pediatrics PRI, University of Louisville, School of Medicine, Louisville, KY, USA; Department of Physiology, University of Louisville, School of Medicine, Louisville, KY, USA; Department of Pharmacology & Toxicology, University of Louisville, School of Medicine, Louisville, KY, USA.
| | - Cynthia J Metz
- Department of Pediatrics PRI, University of Louisville, School of Medicine, Louisville, KY, USA; Department of Physiology, University of Louisville, School of Medicine, Louisville, KY, USA
| | - Maurice Dematteis
- University Hospital, Department of Addiction Medicine, Grenoble F-38043, France; Grenoble Alpes University, Faculty of Medicine, Grenoble, F-38042, France
| | - Leroy R Sachleben
- Department of Pediatrics PRI, University of Louisville, School of Medicine, Louisville, KY, USA
| | - Avital Schurr
- Department of Anesthesiology & Perioperative Medicine, University of Louisville, School of Medicine, Louisville, KY, USA
| | - Madhavi J Rane
- Department of Medicine/Nephrology, University of Louisville, School of Medicine, Louisville, KY, USA
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Diers AR, Vayalil PK, Oliva CR, Griguer CE, Darley-Usmar V, Hurst DR, Welch DR, Landar A. Mitochondrial bioenergetics of metastatic breast cancer cells in response to dynamic changes in oxygen tension: effects of HIF-1α. PLoS One 2013; 8:e68348. [PMID: 23840849 DOI: 10.1371/journal.pone.0068348] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 05/28/2013] [Indexed: 11/19/2022] Open
Abstract
Solid tumors are characterized by regions of low oxygen tension (OT), which play a central role in tumor progression and resistance to therapy. Low OT affects mitochondrial function and for the cells to survive, mitochondria must functionally adapt to low OT to maintain the cellular bioenergetics. In this study, a novel experimental approach was developed to examine the real-time bioenergetic changes in breast cancer cells (BCCs) during adaptation to OT (from 20% to <1% oxygen) using sensitive extracellular flux technology. Oxygen was gradually removed from the medium, and the bioenergetics of metastatic BCCs (MDA-MB-231 and MCF10CA clones) was compared with non-tumorigenic (MCF10A) cells. BCCs, but not MCF10A, rapidly responded to low OT by stabilizing HIF-1α and increasing HIF-1α responsive gene expression and glucose uptake. BCCs also increased extracellular acidification rate (ECAR), which was markedly lower in MCF10A. Interestingly, BCCs exhibited a biphasic response in basal respiration as the OT was reduced from 20% to <1%. The initial stimulation of oxygen consumption is found to be due to increased mitochondrial respiration. This effect was HIF-1α-dependent, as silencing HIF-1α abolished the biphasic response. During hypoxia and reoxygenation, BCCs also maintained oxygen consumption rates at specific OT; however, HIF-1α silenced BCC were less responsive to changes in OT. Our results suggest that HIF-1α provides a high degree of bioenergetic flexibility under different OT which may confer an adaptive advantage for BCC survival in the tumor microenvironment and during invasion and metastasis. This study thus provides direct evidence for the cross-talk between HIF-1α and mitochondria during adaptation to low OT by BCCs and may be useful in identifying novel therapeutic agents that target the bioenergetics of BCCs in response to low OT.
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Li W, Hu ZF, Chen B, Ni GX. Response of C2C12 myoblasts to hypoxia: the relative roles of glucose and oxygen in adaptive cellular metabolism. Biomed Res Int 2013; 2013:326346. [PMID: 24294605 PMCID: PMC3835707 DOI: 10.1155/2013/326346] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 09/22/2013] [Accepted: 09/23/2013] [Indexed: 02/08/2023]
Abstract
BACKGROUND Oxygen and glucose are two important nutrients for mammalian cell function. In this study, the effect of glucose and oxygen concentrations on C2C12 cellular metabolism was characterized with an emphasis on detecting whether cells show oxygen conformance (OC) in response to hypoxia. METHODS After C2C12 cells being cultured in the levels of glucose at 0.6 mM (LG), 5.6 mM (MG), or 23.3 mM(HG) under normoxic or hypoxic (1% oxygen) condition, cellular oxygen consumption, glucose consumption, lactate production, and metabolic status were determined. Short-term oxygen consumption was measured with a novel oxygen biosensor technique. Longer-term measurements were performed with standard glucose, lactate, and cell metabolism assays. RESULTS It was found that oxygen depletion in normoxia is dependent on the glucose concentration in the medium. Cellular glucose uptake and lactate production increased significantly in hypoxia than those in normoxia. In hypoxia the cellular response to the level of glucose was different to that in normoxia. The metabolic activities decreased while glucose concentration increased in normoxia, while in hypoxia, metabolic activity was reduced in LG and MG, but unchanged in HG condition. The OC phenomenon was not observed in the present study. CONCLUSIONS Our findings suggested that a combination of low oxygen and low glucose damages the viability of C2C12 cells more seriously than low oxygen alone. In addition, when there is sufficient glucose, C2C12 cells will respond to hypoxia by upregulating anaerobic respiration, as shown by lactate production.
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Affiliation(s)
- Wei Li
- 1Clinical Medicine Education Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Zhen-Fu Hu
- 2Department of Plastic Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Bin Chen
- 3Department of Orthopaedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Guo-Xin Ni
- 3Department of Orthopaedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
- *Guo-Xin Ni:
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Kamga C, Krishnamurthy S, Shiva S. Myoglobin and mitochondria: a relationship bound by oxygen and nitric oxide. Nitric Oxide 2012; 26:251-8. [PMID: 22465476 DOI: 10.1016/j.niox.2012.03.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 03/22/2012] [Indexed: 01/04/2023]
Abstract
Since their initial discovery over a century ago, our knowledge of the functions of myoglobin and the mitochondrion has gradually evolved. The mitochondrion, once thought to be solely responsible for energy production, is now known to be an integral redox and apoptotic signal transducer within the cell. Likewise, myoglobin, traditionally thought of only as an oxygen store, has emerged as a physiological catalyst that can modulate reactive oxygen species levels, facilitate oxygen diffusion and scavenge or generate nitric oxide (NO) depending on oxygen tensions within the cell. By virtue of its unique ability to regulate O(2) and NO levels within the cell, myoglobin can modulate mitochondrial function in energy-demanding tissues such as the beating heart and exercising muscle. In this review, we present the conventional functions of myoglobin and mitochondria, and describe how these roles have been reassessed and advanced, particularly in the context of NO and nitrite signaling. We present the mechanisms by which mitochondria and myoglobin regulate one another within the cell through their interactions with NO and oxygen and discuss the implications of these interactions in terms of health and disease.
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Affiliation(s)
- Christelle Kamga
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15261, United States
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Niu Y, Li S, Na L, Feng R, Liu L, Li Y, Sun C. Mangiferin decreases plasma free fatty acids through promoting its catabolism in liver by activation of AMPK. PLoS One 2012; 7:e30782. [PMID: 22292039 DOI: 10.1371/journal.pone.0030782] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 12/27/2011] [Indexed: 12/23/2022] Open
Abstract
Mangiferin has been shown to have the effect of improving dyslipidemia. Plasma free fatty acids (FFA) are closely associated with blood lipid metabolism as well as many diseases including metabolic syndrome. This study is to investigate whether mangiferin has effects on FFA metabolism in hyperlipidemic rats. Wistar rats were fed a high-fat diet and administered mangiferin simultaneously for 6 weeks. Mangiferin (50, 100, 150 mg/kg BW) decreased dose-dependently FFA and triglycerides (TG) levels in plasma, and their accumulations in liver, but increased the β-hydroxybutyrate levels in both plasma and liver of hyperlipidemic rats. HepG2 cells were treated with oleic acid (OA, 0.2 mmol/L) to simulate the condition of high level of plasma FFA in vitro, and were treated with different concentrations of mangiferin simultaneously for 24 h. We found that mangiferin significantly increased FFA uptake, significantly decreased intracellular FFA and TG accumulations in HepG2 cells. Mangiferin significantly increased AMP-activated protein kinase (AMPK) phosphorylation and its downstream proteins involved in fatty acid translocase (CD36) and carnitine palmitoyltransferase 1 (CPT1), but significantly decreased acyl-CoA: diacylgycerol acyltransferase 2 (DGAT2) expression and acetyl-CoA carboxylase (ACC) activity by increasing its phosphorylation level in both in vivo and in vitro studies. Furthermore, these effects were reversed by Compound C, an AMPK inhibitor in HepG2 cells. For upstream of AMPK, mangiferin increased AMP/ATP ratio, but had no effect on LKB1 phosphorylation. In conclusion, mangiferin decreased plasma FFA levels through promoting FFA uptake and oxidation, inhibiting FFA and TG accumulations by regulating the key enzymes expression in liver through AMPK pathway. Therefore, mangiferin is a possible beneficial natural compound for metabolic syndrome by improving FFA metabolism.
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Dada L, Gonzalez AR, Urich D, Soberanes S, Manghi TS, Chiarella SE, Chandel NS, Budinger GRS, Mutlu GM. Alcohol worsens acute lung injury by inhibiting alveolar sodium transport through the adenosine A1 receptor. PLoS One 2012; 7:e30448. [PMID: 22272351 PMCID: PMC3260305 DOI: 10.1371/journal.pone.0030448] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Accepted: 12/16/2011] [Indexed: 12/14/2022] Open
Abstract
Objective Alcohol intake increases the risk of acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS) and is associated with poor outcomes in patients who develop these syndromes. No specific therapies are currently available to treat or decrease the risk of ARDS in patients with alcoholism. We have recently shown increased levels of lung adenosine inhibit alveolar fluid clearance, an important predictor of outcome in patients with ARDS. We hypothesized that alcohol might worsen lung injury by increasing lung adenosine levels, resulting in impaired active Na+ transport in the lung. Methods We treated wild-type mice with alcohol administered i.p. to achieve blood alcohol levels associated with moderate to severe intoxication and measured the rate of alveolar fluid clearance and Na,K-ATPase expression in peripheral lung tissue and assessed the effect of alcohol on survival during exposure to hyperoxia. We used primary rat alveolar type II cells to investigate the mechanisms by which alcohol regulates alveolar Na+ transport. Results Exposure to alcohol reduced alveolar fluid clearance, downregulated Na,K-ATPase in the lung tissue and worsened hyperoxia-induced lung injury. Alcohol caused an increase in BAL fluid adenosine levels. A similar increase in lung adenosine levels was observed after exposure to hyperoxia. In primary rat alveolar type II cells alcohol and adenosine decreased the abundance of the Na,K-ATPase at the basolateral membrane via a mechanism that required activation of the AMPK. Conclusions Alcohol decreases alveolar fluid clearance and impairs survival from acute lung injury. Alcohol induced increases in lung adenosine levels may be responsible for reduction in alveolar fluid clearance and associated worsening of lung injury.
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Affiliation(s)
- Laura Dada
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Angel R. Gonzalez
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Daniela Urich
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Saul Soberanes
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Tomas S. Manghi
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Sergio E. Chiarella
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Navdeep S. Chandel
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - G. R. Scott Budinger
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Gökhan M. Mutlu
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
- * E-mail:
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13
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Mutharasan RK, Nagpal V, Ichikawa Y, Ardehali H. microRNA-210 is upregulated in hypoxic cardiomyocytes through Akt- and p53-dependent pathways and exerts cytoprotective effects. Am J Physiol Heart Circ Physiol 2011; 301:H1519-30. [PMID: 21841015 DOI: 10.1152/ajpheart.01080.2010] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
microRNA-210 (miR-210) is upregulated in hypoxia, but its function in cardiomyocytes and its regulation in response to hypoxia are not well characterized. The purpose of this study was to identify upstream regulators of miR-210, as well as to characterize miR-210's function in cardiomyocytes. We first showed miR-210 is upregulated through both hypoxia-inducible factor (HIF)-dependent and -independent pathways, since aryl hydrocarbon nuclear translocator (ARNT) knockout mouse embryonic fibroblasts (MEF), lacking intact HIF signaling, still displayed increased miR-210 levels in hypoxia. To determine the mechanism for HIF-independent regulation of miR-210, we focused on p53 and protein kinase B (Akt). Overexpression of p53 in wild-type MEFs induced miR-210, whereas p53 overexpression in ARNT knockout MEFs did not, suggesting p53 regulates miR-210 in a HIF-dependent mechanism. Akt inhibition reduced miR-210 induction by hypoxia, whereas Akt overexpression increased miR-210 levels in both wild-type and ARNT knockout MEFs, indicating Akt regulation of miR-210 is HIF-independent. We then studied the effects of miR-210 in cardiomyocytes. Overexpression of miR-210 reduced cell death in response to oxidative stress and reduced reactive oxygen species (ROS) production both at baseline and after treatment with antimycin A. Furthermore, downregulation of miR-210 increased ROS after hypoxia-reoxygenation. To determine a mechanism for the cytoprotective effects of miR-210, we focused on the predicted target, apoptosis-inducing factor, mitochondrion-associated 3 (AIFM3), known to induce cell death. Although miR-210 reduced AIFM3 levels, overexpression of AIFM3 in the presence of miR-210 overexpression did not reduce cellular viability either at baseline or after hydrogen peroxide treatment, suggesting AIFM3 does not mediate miR-210's cytoprotective effects. Furthermore, HIF-3α, a negative regulator of HIF signaling, is targeted by miR-210, but miR-210 does not modulate HIF activity. In conclusion, we demonstrate a novel role for p53 and Akt in regulating miR-210 and demonstrate that, in cardiomyocytes, miR-210 exerts cytoprotective effects, potentially by reducing mitochondrial ROS production.
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Affiliation(s)
- R Kannan Mutharasan
- Feinberg Cardiovascular Research Institute, Northwestern University, Chicago, Illinois 60611, USA
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14
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Gusarova GA, Trejo HE, Dada LA, Briva A, Welch LC, Hamanaka RB, Mutlu GM, Chandel NS, Prakriya M, Sznajder JI. Hypoxia leads to Na,K-ATPase downregulation via Ca(2+) release-activated Ca(2+) channels and AMPK activation. Mol Cell Biol 2011; 31:3546-56. [PMID: 21730292 DOI: 10.1128/MCB.05114-11] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
To maintain cellular ATP levels, hypoxia leads to Na,K-ATPase inhibition in a process dependent on reactive oxygen species (ROS) and the activation of AMP-activated kinase α1 (AMPK-α1). We report here that during hypoxia AMPK activation does not require the liver kinase B1 (LKB1) but requires the release of Ca(2+) from the endoplasmic reticulum (ER) and redistribution of STIM1 to ER-plasma membrane junctions, leading to calcium entry via Ca(2+) release-activated Ca(2+) (CRAC) channels. This increase in intracellular Ca(2+) induces Ca(2+)/calmodulin-dependent kinase kinase β (CaMKKβ)-mediated AMPK activation and Na,K-ATPase downregulation. Also, in cells unable to generate mitochondrial ROS, hypoxia failed to increase intracellular Ca(2+) concentration while a STIM1 mutant rescued the AMPK activation, suggesting that ROS act upstream of Ca(2+) signaling. Furthermore, inhibition of CRAC channel function in rat lungs prevented the impairment of alveolar fluid reabsorption caused by hypoxia. These data suggest that during hypoxia, calcium entry via CRAC channels leads to AMPK activation, Na,K-ATPase downregulation, and alveolar epithelial dysfunction.
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Mungai PT, Waypa GB, Jairaman A, Prakriya M, Dokic D, Ball MK, Schumacker PT. Hypoxia triggers AMPK activation through reactive oxygen species-mediated activation of calcium release-activated calcium channels. Mol Cell Biol 2011; 31:3531-45. [PMID: 21670147 DOI: 10.1128/MCB.05124-11] [Citation(s) in RCA: 295] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
AMP-activated protein kinase (AMPK) is an energy sensor activated by increases in [AMP] or by oxidant stress (reactive oxygen species [ROS]). Hypoxia increases cellular ROS signaling, but the pathways underlying subsequent AMPK activation are not known. We tested the hypothesis that hypoxia activates AMPK by ROS-mediated opening of calcium release-activated calcium (CRAC) channels. Hypoxia (1.5% O(2)) augments cellular ROS as detected by the redox-sensitive green fluorescent protein (roGFP) but does not increase the [AMP]/[ATP] ratio. Increases in intracellular calcium during hypoxia were detected with Fura2 and the calcium-calmodulin fluorescence resonance energy transfer (FRET) sensor YC2.3. Antioxidant treatment or removal of extracellular calcium abrogates hypoxia-induced calcium signaling and subsequent AMPK phosphorylation during hypoxia. Oxidant stress triggers relocation of stromal interaction molecule 1 (STIM1), the endoplasmic reticulum (ER) Ca(2+) sensor, to the plasma membrane. Knockdown of STIM1 by short interfering RNA (siRNA) attenuates the calcium responses to hypoxia and subsequent AMPK phosphorylation, while inhibition of L-type calcium channels has no effect. Knockdown of the AMPK upstream kinase LKB1 by siRNA does not prevent AMPK activation during hypoxia, but knockdown of CaMKKβ abolishes the AMPK response. These findings reveal that hypoxia can trigger AMPK activation in the apparent absence of increased [AMP] through ROS-dependent CRAC channel activation, leading to increases in cytosolic calcium that activate the AMPK upstream kinase CaMKKβ.
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Tsou P, Zheng B, Hsu CH, Sasaki AT, Cantley LC. A fluorescent reporter of AMPK activity and cellular energy stress. Cell Metab 2011; 13:476-486. [PMID: 21459332 PMCID: PMC3070961 DOI: 10.1016/j.cmet.2011.03.006] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Revised: 01/19/2011] [Accepted: 02/25/2011] [Indexed: 11/28/2022]
Abstract
AMP-activated protein kinase (AMPK) is activated when the AMP/ATP ratio in cells is elevated due to energy stress. Here, we describe a biosensor, AMPKAR, that exhibits enhanced fluorescence resonance energy transfer (FRET) in response to phosphorylation by AMPK, allowing spatiotemporal monitoring of AMPK activity in single cells. We show that this reporter responds to a variety of stimuli that are known to induce energy stress and that the response is dependent on AMPK α1 and α2 and on the upstream kinase LKB1. Interestingly, we found that AMPK activation is confined to the cytosol in response to energy stress but can be observed in both the cytosol and nucleus in response to calcium elevation. Finally, using this probe with U2OS cells in a microfluidic device, we observed a very high cell-to-cell variability in the amplitude and time course of AMPK activation and recovery in response to pulses of glucose deprivation.
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Affiliation(s)
- Peiling Tsou
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA; Division of Signal Transduction, Beth Israel Deaconess Medical Center, Boston, MA 02115, USA
| | - Bin Zheng
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA; Division of Signal Transduction, Beth Israel Deaconess Medical Center, Boston, MA 02115, USA
| | - Chia-Hsien Hsu
- BioMEMS Resource Center, Center for Engineering in Medicine and Surgical Services, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Atsuo T Sasaki
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA; Division of Signal Transduction, Beth Israel Deaconess Medical Center, Boston, MA 02115, USA
| | - Lewis C Cantley
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA; Division of Signal Transduction, Beth Israel Deaconess Medical Center, Boston, MA 02115, USA.
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17
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Abstract
Adaptation to lowering oxygen levels (hypoxia) requires coordinated downregulation of metabolic demand and supply to prevent a mismatch in ATP utilization and production that might culminate in a bioenergetic collapse. Hypoxia diminishes ATP utilization by downregulating protein translation and the activity of the Na-K-ATPase. Hypoxia diminishes ATP production in part by lowering the activity of the electron transport chain through activation of the transcription factor hypoxia-inducible factor-1. The decrease in electron transport limits the overproduction of reactove oxygen species during hypoxia and slows the rate of oxygen depletion to prevent anoxia. In this review, we discuss these mechanisms that diminish metabolic supply and demand for adaptation to hypoxia.
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Affiliation(s)
- William W Wheaton
- Division of Pulmonary & Critical Care Medicine, 240 East Huron Ave., McGraw M-334, Chicago, IL 60611-2909, USA
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18
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Abstract
The transcription factors hypoxia inducible factors 1 and 2 (HIF-1 and HIF-2) regulate multiple responses to physiological hypoxia such as transcription of the hormone erythropoietin to enhance red blood cell proliferation, vascular endothelial growth factor to promote angiogenesis and glycolytic enzymes to increase glycolysis. Recent studies indicate that HIFs also regulate mitochondrial respiration and mitochondrial oxidative stress. Interestingly, mitochondrial metabolism, respiration and oxidative stress also regulate activation of HIFs. In this review, we examine the evidence that mitochondria and HIFs are intimately connected to regulate each other resulting in appropriate responses to hypoxia.
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Affiliation(s)
- Kathryn V Tormos
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, Northwestern University Medical School, Chicago, IL 60611-2909, USA
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19
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Na N, Chandel NS, Litvan J, Ridge KM. Mitochondrial reactive oxygen species are required for hypoxia-induced degradation of keratin intermediate filaments. FASEB J 2009; 24:799-809. [PMID: 19897662 DOI: 10.1096/fj.08-128967] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Hypoxia can cause stress and structural changes to the epithelial cytoskeleton. The intermediate filament (IF) network is known to reorganize in response to stress. We examined whether rats exposed to hypoxia had altered keratin IF expression in their alveolar epithelial type II (ATII) cells. There was a significant decrease in keratin protein levels in hypoxic ATII cells compared with those in ATII cells isolated from normoxic rats. To define the mechanisms regulating this process we studied changes to the keratin IF network in A549 cells (an alveolar epithelial cell line) exposed to 1.5% oxygen. We observed a time-dependent disassembly-degradation of keratin 8 and 18 proteins, which was associated with an increase in reactive oxygen species (ROS). Hypoxia-treated A549 cells deficient in mitochondrial DNA or A549 cells treated with a small interfering RNA against the Rieske iron-sulfur protein of mitochondrial complex III did not have increased levels of ROS nor was the keratin IF network disassembled and degraded. The superoxide dismutase (SOD)/catalase mimetic (EUK-134) prevented the hypoxia-mediated keratin IF degradation as did the overexpression of SOD1 but not of SOD2. Accordingly, we provide evidence that hypoxia promotes the disassembly and degradation of the keratin IF network via mitochondrial complex III-generated reactive oxygen species.-Na, N., Chandel, N. S., Litvan, J., Ridge, K. M. Mitochondrial reactive oxygen species are required for hypoxia-induced degradation of keratin intermediate filaments.
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Affiliation(s)
- Ni Na
- Northwestern University Medical School, Pulmonary and Critical Care Medicine, 240 East Huron, McGaw 2328, Chicago, IL 60611, USA
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20
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Galkin A, Abramov AY, Frakich N, Duchen MR, Moncada S. Lack of oxygen deactivates mitochondrial complex I: implications for ischemic injury? J Biol Chem 2009; 284:36055-36061. [PMID: 19861410 DOI: 10.1074/jbc.m109.054346] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
For S-nitrosothiols and peroxynitrite to interfere with the activity of mitochondrial complex I, prior transition of the enzyme from its active (A) to its deactive, dormant (D) state is necessary. We now demonstrate accumulation of the D-form of complex I in human epithelial kidney cells after prolonged hypoxia. Upon reoxygenation after hypoxia there was an initial delay in the return of the respiration rate to normal. This was due to the accumulation of the D-form and its slow, substrate-dependent reconversion to the A-form. Reconversion to the A-form could be prevented by prolonged incubation with endogenously generated NO. We propose that the hypoxic transition from the A-form to the D-form of complex I may be protective, because it would act to reduce the electron burst and the formation of free radicals during reoxygenation. However, this may become an early pathophysiological event when NO-dependent formation of S-nitrosothiols or peroxynitrite structurally modifies complex I in its D-form and impedes its return to the active state. These observations provide a mechanism to account for the severe cell injury that follows hypoxia and reoxygenation when accompanied by NO generation.
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Affiliation(s)
- Alexander Galkin
- Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT.
| | - Andrey Y Abramov
- Department of Molecular Neuroscience, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, United Kingdom
| | - Nanci Frakich
- Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT
| | - Michel R Duchen
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT
| | - Salvador Moncada
- Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT
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21
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Wang L, Wilshaw SP, Korossis S, Fisher J, Jin Z, Ingham E. Factors Influencing the Oxygen Consumption Rate of Aortic Valve Interstitial Cells: Application to Tissue Engineering. Tissue Eng Part C Methods 2009; 15:355-63. [DOI: 10.1089/ten.tec.2008.0415] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Ling Wang
- Institute of Medical and Biological Engineering, University of Leeds, Leeds, United Kingdom
| | - Stacy-Paul Wilshaw
- Institute of Medical and Biological Engineering, University of Leeds, Leeds, United Kingdom
| | - Sotirios Korossis
- Institute of Medical and Biological Engineering, University of Leeds, Leeds, United Kingdom
| | - John Fisher
- Institute of Medical and Biological Engineering, University of Leeds, Leeds, United Kingdom
| | - Zhongmin Jin
- Institute of Medical and Biological Engineering, University of Leeds, Leeds, United Kingdom
| | - Eileen Ingham
- Institute of Medical and Biological Engineering, University of Leeds, Leeds, United Kingdom
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22
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Emerling BM, Weinberg F, Snyder C, Burgess Z, Mutlu GM, Viollet B, Budinger GS, Chandel NS. Hypoxic activation of AMPK is dependent on mitochondrial ROS but independent of an increase in AMP/ATP ratio. Free Radic Biol Med 2009; 46:1386-91. [PMID: 19268526 PMCID: PMC3326346 DOI: 10.1016/j.freeradbiomed.2009.02.019] [Citation(s) in RCA: 241] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Revised: 02/12/2009] [Accepted: 02/24/2009] [Indexed: 10/21/2022]
Abstract
AMP-activated protein kinase (AMPK) is a sensor of cellular energy status found in metazoans that is known to be activated by stimuli that increase the cellular AMP/ATP ratio. Full activation of AMPK requires specific phosphorylation within the activation loop of the catalytic domain of the alpha-subunit by upstream kinases such as the serine/threonine protein kinase LKB1. Here we show that hypoxia activates AMPK through LKB1 without an increase in the AMP/ATP ratio. Hypoxia increased reactive oxygen species (ROS) levels and the antioxidant EUK-134 abolished the hypoxic activation of AMPK. Cells deficient in mitochondrial DNA (rho(0) cells) failed to activate AMPK during hypoxia but are able to in the presence of exogenous H(2)O(2). Furthermore, we provide genetic evidence that ROS generated within the mitochondrial electron transport chain and not oxidative phosphorylation is required for hypoxic activation of AMPK. Collectively, these data indicate that oxidative stress and not an increase in the AMP/ATP ratio is required for hypoxic activation of AMPK.
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Affiliation(s)
- Brooke M. Emerling
- Department of Medicine, Northwestern University Medical School, Chicago, IL 60611, USA
| | - Frank Weinberg
- Department of Medicine, Northwestern University Medical School, Chicago, IL 60611, USA
| | - Colleen Snyder
- Department of Medicine, Northwestern University Medical School, Chicago, IL 60611, USA
| | - Zach Burgess
- Department of Medicine, Northwestern University Medical School, Chicago, IL 60611, USA
| | - Gökhan M. Mutlu
- Department of Medicine, Northwestern University Medical School, Chicago, IL 60611, USA
| | - Benoit Viollet
- Institut Cochin, Université Paris Descartes, CNRS (UMR 8104), Paris, France
- Inserm, U567, Paris, France
| | - G.R. Scott Budinger
- Department of Medicine, Northwestern University Medical School, Chicago, IL 60611, USA
| | - Navdeep S. Chandel
- Department of Medicine, Northwestern University Medical School, Chicago, IL 60611, USA
- Corresponding author. Fax: +1 312 503 0411. .
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23
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Wang L, Wilshaw SP, Korossis S, Fisher J, Jin Z, Ingham E. Factors Influencing the Oxygen Consumption Rate of Aortic Valve Interstitial Cells: Application to Tissue Engineering. Tissue Eng Part A 2009. [DOI: 10.1089/ten.tea.2008.0415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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24
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Tengan CH, Kiyomoto BH, Godinho RO, Gamba J, Neves AC, Schmidt B, Oliveira ASB, Gabbai AA. The role of nitric oxide in muscle fibers with oxidative phosphorylation defects. Biochem Biophys Res Commun 2007; 359:771-7. [PMID: 17560547 DOI: 10.1016/j.bbrc.2007.05.184] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2007] [Accepted: 05/25/2007] [Indexed: 11/30/2022]
Abstract
NO has been pointed as an important player in the control of mitochondrial respiration, especially because of its inhibitory effect on cytochrome c oxidase (COX). However, all the events involved in this control are still not completely elucidated. We demonstrate compartmentalized abnormalities on nitric oxide synthase (NOS) activity on muscle biopsies of patients with mitochondrial diseases. NOS activity was reduced in the sarcoplasmic compartment in COX deficient fibers, whereas increased activity was found in the sarcolemma of fibers with mitochondrial proliferation. We observed increased expression of neuronal NOS (nNOS) in patients and a correlation between nNOS expression and mitochondrial content. Treatment of skeletal muscle culture with an NO donor induced an increase in mitochondrial content. Our results indicate specific roles of NO in compensatory mechanisms of muscle fibers with mitochondrial deficiency and suggest the participation of nNOS in the signaling process of mitochondrial proliferation in human skeletal muscle.
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Affiliation(s)
- Célia H Tengan
- Department of Neurology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil.
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25
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Abstract
The characteristic structural organization of mitochondria is the product of synthesis of macromolecules within the mitochondria together with the import of proteins and lipids synthesized outside the organelle. Synthetic and import processes are required for mitochondrial proliferation and might also facilitate the growth of pre-existing mitochondria. Recent evidence indicates that these events are regulated in a complex way by several agonists and environmental conditions, through activation of specific signaling pathways and transcription factors. A newly discovered role of this organelle in retrograde intracellular signaling back to the nucleus has also emerged. This is likely to have far-reaching implications in development, aging, disease and environmental adaptation. Generation of nitric oxide (NO) appears to be an important player in these processes, possibly acting as a unifying molecular switch to trigger the whole mitochondrial biogenesis process. High levels of NO acutely inhibit cell respiration by binding to cytochrome c oxidase. Conversely, chronic, smaller increases in NO levels stimulate mitochondrial biogenesis in diverse cell types. NO-induced mitochondrial biogenesis seems to be linked to proliferation and differentiation of normal and tumor cells, as well as in aging.
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Affiliation(s)
- Enzo Nisoli
- Department of Pharmacology, Chemotherapy and Medical Toxicology, School of Medicine, Milan University, via Vanvitelli 32, 20129 Milan, Italy.
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26
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Kulisz A, Chen N, Chandel NS, Shao Z, Schumacker PT. Mitochondrial ROS initiate phosphorylation of p38 MAP kinase during hypoxia in cardiomyocytes. Am J Physiol Lung Cell Mol Physiol 2002; 282:L1324-9. [PMID: 12003789 DOI: 10.1152/ajplung.00326.2001] [Citation(s) in RCA: 199] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The p38 mitogen-activated protein kinase (MAPK) is phosphorylated in response to oxidative stress. Mitochondria in cardiomyocytes increase their generation of reactive oxygen species (ROS) during hypoxia (1-5% O(2)). These ROS participate in signal transduction pathways involved in adaptive responses, including ischemic preconditioning and gene transcription. The present study therefore tested the hypothesis that hypoxia induces p38 MAPK phosphorylation by augmenting mitochondrial ROS generation. In cardiomyocytes, phosphorylation of p38 was observed in a PO(2)-dependent manner during hypoxia. This response was inhibited by rotenone, thenoyltrifluoroacetone, and myxothiazol, inhibitors of mitochondrial complexes I, II, and III, respectively. A similar inhibition was observed in the cells pretreated with anion channel inhibitor DIDS, which may block ROS release from mitochondria. During normoxia, increases in mitochondrial ROS elicited by azide (1-2 mM) or by the mitochondrial inhibitor antimycin A caused increased phosphorylation of p38. Brief treatment with exogenous H(2)O(2) during normoxia also induced phosphorylation of p38 as hypoxia, but this effect was not abolished by myxothiazol or DIDS. The antioxidant N-acetyl-cysteine abolished the p38 response to hypoxia, presumably by scavenging H(2)O(2), but the mitogen extracellular receptor kinase inhibitor PD-98059 did not inhibit p38 phosphorylation during hypoxia. Thus physiological hypoxia leads to p38 phosphorylation through a mechanism that requires electron flux in the proximal region of the mitochondrial electron transport chain, which suggests that either H(2)O(2) or superoxide participates in activating that process.
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Affiliation(s)
- Andre Kulisz
- Pulmonary and Critical Care Medicine, The University of Chicago, Chicago, Illinois 60637, USA
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27
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Turcotte ML, Parliament M, Franko A, Allalunis-Turner J. Variation in mitochondrial function in hypoxia-sensitive and hypoxia-tolerant human glioma cells. Br J Cancer 2002; 86:619-24. [PMID: 11870546 PMCID: PMC2375290 DOI: 10.1038/sj.bjc.6600087] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2001] [Revised: 09/20/2001] [Accepted: 11/19/2001] [Indexed: 11/18/2022] Open
Abstract
We have shown previously that human glioblastoma multiforme cells vary in their ability to survive under hypoxic conditions. Under oxygen limiting conditions, hypoxia-tolerant cells decrease their oxygen consumption rate whereas hypoxia-sensitive cells continue to consume oxygen at a relatively steady rate until the oxygen supply becomes exhausted. We now show that hypoxia-tolerant and hypoxia-sensitive cells exhibit distinct patterns of mitochondrial function in response to hypoxic challenge. Hypoxia-tolerant cell lines retain stable mitochondrial membrane potential and ATP concentration when incubated under oxygen limiting conditions. In addition, hypoxia-tolerant cell lines are consistently more sensitive to a wide spectrum of inhibitors of mitochondrial function than are hypoxia-sensitive cells. In contrast, the hypoxia-sensitive cells are unable to maintain stable mitochondrial membrane potential and ATP levels when incubated at reduced oxygen tension. These results demonstrate significant differences in the mitochondrial function between these two phenotypes and reinforce previous data that suggest a regulatory role for mitochondria in the development of hypoxia tolerance.
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Affiliation(s)
- M L Turcotte
- Department of Oncology, University of Alberta, Edmonton, Alberta, Canada
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28
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Abstract
SUMMARYMost animals experience some degree of hypoxia and hypothermia during the course of their natural life history either as a consequence of ambient ‘exposure’ per se or through metabolic, respiratory and/or circulatory insufficiency. A prevailing experimental approach has been to probe tissues from natural models of hypoxia-tolerant and cold-tolerant vertebrates to look for common mechanisms of defence against O2 lack and hypothermia. The ability to sustain vital cellular functions in severe cases of either condition varies widely amongst the vertebrates. Like humans, the vast majority of mammals are unable to survive prolonged periods of hypothermia or O2 deprivation owing to irreversible membrane damage and loss of cellular ion homeostasis in vital organs such as the brain and heart. However, numerous hibernating endotherms, neonatal and diving mammals as well as many ectotherms can tolerate prolonged periods that would, in clinical terms, be called asphyxia or deep hypothermia. The key to their survival under such conditions lies in an inherent ability to downregulate their cellular metabolic rate to new hypometabolic steady states in a way that balances the ATP demand and ATP supply pathways.
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Affiliation(s)
- R G Boutilier
- Department of Zoology, Downing Street, Cambridge CB2 3EJ, UK.
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29
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Gottlob K, Majewski N, Kennedy S, Kandel E, Robey RB, Hay N. Inhibition of early apoptotic events by Akt/PKB is dependent on the first committed step of glycolysis and mitochondrial hexokinase. Genes Dev 2001; 15:1406-18. [PMID: 11390360 PMCID: PMC312709 DOI: 10.1101/gad.889901] [Citation(s) in RCA: 707] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The serine/threonine kinase Akt/PKB is a major downstream effector of growth factor-mediated cell survival. Activated Akt, like Bcl-2 and Bcl-xL, prevents closure of a PT pore component, the voltage-dependent anion channel (VDAC); intracellular acidification; mitochondrial hyperpolarization; and the decline in oxidative phosphorylation that precedes cytochrome c release. However, unlike Bcl-2 and Bcl-xL, the ability of activated Akt to preserve mitochondrial integrity, and thereby inhibit apoptosis, requires glucose availability and is coupled to its metabolism. Hexokinases are known to bind to VDAC and directly couple intramitochondrial ATP synthesis to glucose metabolism. We provide evidence that such coupling serves as a downstream effector function for Akt. First, Akt increases mitochondria-associated hexokinase activity. Second, the antiapoptotic activity of Akt requires only the first committed step of glucose metabolism catalyzed by hexokinase. Finally, ectopic hexokinase expression mimics the ability of Akt to inhibit cytochrome c release and apoptosis. We therefore propose that Akt increases coupling of glucose metabolism to oxidative phosphorylation and regulates PT pore opening via the promotion of hexokinase-VDAC interaction at the outer mitochondrial membrane.
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Affiliation(s)
- K Gottlob
- Department of Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60607, USA
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30
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Abstract
Hypoxia elicits a variety of adaptive responses at the tissue level, at the cellular level, and at the molecular level. A physiological response to hypoxia requires the existence of an O(2) sensor coupled to a signal transduction system, which in turn activates the functional response. Although much has been learned about the signaling systems activated by hypoxia, no consensus exists regarding the nature of the underlying O(2) sensor or whether multiple sensors exist. Among previously considered mechanisms, heme proteins have been suggested to undergo allosteric modification in response to O(2) binding or release at different PO(2) levels. Other studies suggest that ion channels may change conductance as a function of PO(2), allowing them to signal the onset of hypoxia. Still other studies suggest that NADPH oxidase may decrease its generation of reactive O(2) species (ROS) during hypoxia. Recent data suggest that mitochondria may function as O(2) sensors by increasing their generation of ROS during hypoxia. These oxidant signals appear to act as second messengers in the adaptive responses to hypoxia in a variety of cell types. Such observations contribute to a growing awareness that mitochondria do more than just generate ATP, in that they initiate signaling cascades involved in adaptive responses to hypoxia and that they participate in the control of cell death pathways.
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Affiliation(s)
- N S Chandel
- The University of Chicago, Pulmonary and Critical Care Medicine, Chicago, Illinois 60637, USA
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Vander Heiden MG, Chandel NS, Li XX, Schumacker PT, Colombini M, Thompson CB. Outer mitochondrial membrane permeability can regulate coupled respiration and cell survival. Proc Natl Acad Sci U S A 2000; 97:4666-71. [PMID: 10781072 PMCID: PMC18290 DOI: 10.1073/pnas.090082297] [Citation(s) in RCA: 322] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Coupled cellular respiration requires that ATP and ADP be efficiently exchanged between the cytosol and the mitochondrial matrix. When growth factors are withdrawn from dependent cells, metabolism is disrupted by a defect in ATP/ADP exchange across the mitochondrial membranes. Unexpectedly, we find that this defect results from loss of outer mitochondrial membrane permeability to metabolic anions. This decrease in anion permeability correlates with the changes in conductance properties that accompany closure of the voltage-dependent anion channel (also known as mitochondrial porin). Loss of outer membrane permeability (i) results in the accumulation of stored metabolic energy within the intermembrane space in the form of creatine phosphate, (ii) is prevented by the outer mitochondrial membrane proteins Bcl-x(L) and Bcl-2, and (iii) can be reversed by growth factor readdition. If outer membrane impermeability persists, the disruption of mitochondrial homeostasis culminates in loss of outer mitochondrial membrane integrity, cytochrome c redistribution, and apoptosis. The recognition that outer membrane permeability is regulated under physiological conditions has important implications for the understanding of bioenergetics and cell survival.
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Affiliation(s)
- M G Vander Heiden
- Gwen Knapp Center and Committee on Immunology, University of Chicago, Chicago, IL 60637, USA
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Clementi E, Brown GC, Foxwell N, Moncada S. On the mechanism by which vascular endothelial cells regulate their oxygen consumption. Proc Natl Acad Sci U S A 1999; 96:1559-62. [PMID: 9990063 PMCID: PMC15516 DOI: 10.1073/pnas.96.4.1559] [Citation(s) in RCA: 243] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Two enzymes, soluble guanylyl cyclase and cytochrome c oxidase, have been shown to be exquisitely sensitive to nitric oxide (NO) at low physiological concentrations. Activation of the soluble guanylyl cyclase by endogenous NO and the consequent increase in the second messenger cyclic GMP are now known to control a variety of biological functions. Cytochrome c oxidase, the terminal enzyme of the mitochondrial respiratory chain, is inhibited by NO. However, it is not clear whether NO produced by the constitutive NO synthase interacts with cytochrome c oxidase, nor is it known what the biological consequences of such an interaction might be. We now show that NO generated by vascular endothelial cells under basal and stimulated conditions modulates the respiration of these cells in response to acute changes in oxygen concentration. This action occurs at the cytochrome c oxidase and depends on influx of calcium. Thus, NO plays a physiological role in adjusting the capacity of this enzyme to use oxygen, allowing endothelial cells to adapt to acute changes in their environment.
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Affiliation(s)
- E Clementi
- Wolfson Institute for Biomedical Research, University College London, Tottenham Court Road, London W1P 9LN, United Kingdom
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Martin M, Beauvoit B, Voisin PJ, Canioni P, Guérin B, Rigoulet M. Energetic and morphological plasticity of C6 glioma cells grown on 3-D support; effect of transient glutamine deprivation. J Bioenerg Biomembr 1998; 30:565-78. [PMID: 10206476 DOI: 10.1023/a:1020584517588] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The energetic metabolism of rat C6 glioma cells has been investigated as a function of the proliferative and differentiation states under three-dimensional (3-D) growing conditions on microcarrier beads. First, the transient deprivation of glutamine from the culture medium induced a marked decrease in the growth rate and a differentiation of C6 cells through the oligodendrocytic phenotype. Second, the respiratory capacity of the C6 cells during short-term subcultures with or without glutamine continuously declined as a function of the cell density, in part due to the mitochondrial content decrease. During the transition from the early exponential to the plateau growth phase in glutamine-containing medium, the oxygen consumption rate per single cell decreased concomitantly with a decrease in the glucose consumption and lactate production rates. This phenomenon led to a sixfold decrease in the total ATP production flux, without significantly affecting the cellular ATP/ADP ratio, thus indicating that some ATP-consuming processes were simultaneously suppressed during C6 proliferation. In glutamine-free medium, the cellular ATP/ADP ratio transiently increased due to growth arrest and to a reduced ATP turnover. Moreover, the results indicated that glutamine is not an essential respiratory substrate for rat C6 glioma under short-term glutamine deprivation. Worth noting was the high contribution of the mitochondrial oxidative phosphorylation toward the total ATP synthesis (about 80%), regardless of the proliferation or the differentiation status of the C6 cells.
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Affiliation(s)
- M Martin
- Institut de Biochimie et de Génétique Cellulaires du CNRS, Bordeaux, France
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