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Hosen MHA, Whitworth DJ, Leusch FDL, Yuen N, Bengtson Nash SM. Bioenergetic Shifts in Humpback Whale Fibroblasts Upon Chemical Exposure. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:12313-12319. [PMID: 38958666 DOI: 10.1021/acs.est.3c10595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
Southern Hemisphere humpback whales accumulate persistent and toxic chemicals, which are transported to Antarctica through distant sources and in situ usage. The extreme seasonal migration-associated fast of humpback whales results in the remobilization of persistent and lipophilic environmental contaminants from liberated fat stores. Mitochondria play a key role in lipid metabolism, and any disruption to mitochondrial function is expected to influence whole-organism bioenergetics. It is therefore of interest to advance understanding of the impact of known contaminants of the Antarctic sea-ice ecosystem upon humpback whale cellular bioenergetics. Using cell line-based in vitro testing, this study employed the Seahorse Extracellular Flux Analyzer to study cellular metabolic activity in live humpback whale fibroblast cells. The assay, based on oxygen consumption rate, provides insights into the cause of cellular bioenergetic disruption. Immortalized skin fibroblasts were exposed to four priority environmental chemicals found in the Antarctic sea-ice ecosystem. Our findings reveal chemical-dependent functional alterations and varying bioenergetic profile responses. Chlorpyrifos was observed to decrease mitochondrial basal oxygen consumption; dieldrin increased basal oxygen consumption; trifluralin's impact was dose-specific, and endosulfan displayed no effect. Our results provide unique insights into environmental chemical mechanisms of action on cellular bioenergetics, generating much-needed taxa-specific chemical effect data in support of evidence-based conservation policy and management.
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Affiliation(s)
- Md Hafiz All Hosen
- Centre for Planetary Health and Food Security, School of Environment and Science, Griffith University, 170 Kessels Road, Nathan, QLD 4111, Australia
| | - Deanne J Whitworth
- The School of Veterinary Science, The University of Queensland, Gatton, QLD 4343, Australia
| | - Frederic D L Leusch
- Australian Rivers Institute, School of Environment and Science, Griffith University, Gold Coast, QLD 4222, Australia
| | - Nicholas Yuen
- The School of Veterinary Science, The University of Queensland, Gatton, QLD 4343, Australia
| | - Susan M Bengtson Nash
- Centre for Planetary Health and Food Security, School of Environment and Science, Griffith University, 170 Kessels Road, Nathan, QLD 4111, Australia
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Huang Y, Gu W, Qin Z, Jin Y. Bromuconazole exposure induces cardiac dysfunction by upregulating the expression LEF1. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 933:173113. [PMID: 38735319 DOI: 10.1016/j.scitotenv.2024.173113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 04/18/2024] [Accepted: 05/08/2024] [Indexed: 05/14/2024]
Abstract
With the wide application of bromuconazole (BRO), a kind of triazole fungicide, the environmental problems caused by BRO have been paid more and more attention. In this study, adult male zebrafish were exposed to environmental related concentration and the maximum non-lethal concentration for zebrafish larvae (0,50 ng/L and 7.5 mg/L) for 7 days, respectively. Zebrafish exposed to BRO exhibited a significant reduction in body length and an increase in fatness index, indicating adverse physiological changes. Notably, the exposed zebrafish showed enlarged heart ventricular volumes and thinner heart walls. Transcriptome analysis of heart samples showed that BRO exposure mainly affected pathways related to cardiac energy metabolism. In addition, the amount of ATP in the heart tissue was correspondingly reduced, and the expression levels of genes related to controlling ion balance and myosin synthesis in the heart were also altered. The study extended its findings to the rat cardiomyocytes (H9C2), where similar cardiotoxic effects including changes in transcription of genes related to energy metabolism and heart function were also observed, suggesting a potential universal mechanism of BRO-induced cardiotoxicity. In a doxorubicin (DOX) induced larval zebrafish heart failure model, the expression of lymphoid enhancer-binding factor 1(LEF1), a key gene in the Wnt/β-catenin signaling pathway, was significantly increased in larval zebrafish and adult fish heart tissues and cardiomyocytes, suggesting that LEF1 might play an important role in BRO-induced cardiotoxicity. Taken together, BRO exposure could interfere with cardiac function and metabolic capacity by abnormal activation the expression of LEF1. The study emphasized the urgent need for monitoring and regulating BRO due to its harmful effects on the hearts of aquatic organisms.
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Affiliation(s)
- Yilin Huang
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Weijie Gu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Zhen Qin
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Yuanxiang Jin
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, China.
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Magrì A, Cubisino SAM, Battiato G, Lipari CLR, Conti Nibali S, Saab MW, Pittalà A, Amorini AM, De Pinto V, Messina A. VDAC1 Knockout Affects Mitochondrial Oxygen Consumption Triggering a Rearrangement of ETC by Impacting on Complex I Activity. Int J Mol Sci 2023; 24:ijms24043687. [PMID: 36835102 PMCID: PMC9963415 DOI: 10.3390/ijms24043687] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 02/04/2023] [Accepted: 02/10/2023] [Indexed: 02/16/2023] Open
Abstract
Voltage-Dependent Anion-selective Channel isoform 1 (VDAC1) is the most abundant isoform of the outer mitochondrial membrane (OMM) porins and the principal gate for ions and metabolites to and from the organelle. VDAC1 is also involved in a number of additional functions, such as the regulation of apoptosis. Although the protein is not directly involved in mitochondrial respiration, its deletion in yeast triggers a complete rewiring of the whole cell metabolism, with the inactivation of the main mitochondrial functions. In this work, we analyzed in detail the impact of VDAC1 knockout on mitochondrial respiration in the near-haploid human cell line HAP1. Results indicate that, despite the presence of other VDAC isoforms in the cell, the inactivation of VDAC1 correlates with a dramatic impairment in oxygen consumption and a re-organization of the relative contributions of the electron transport chain (ETC) enzymes. Precisely, in VDAC1 knockout HAP1 cells, the complex I-linked respiration (N-pathway) is increased by drawing resources from respiratory reserves. Overall, the data reported here strengthen the key role of VDAC1 as a general regulator of mitochondrial metabolism.
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Affiliation(s)
- Andrea Magrì
- Department of Biological, Geological and Environmental Sciences, University of Catania, Via S. Sofia 64, 95125 Catania, Italy
- we.MitoBiotech S.R.L., C.so Italia 174, 95125 Catania, Italy
- Correspondence:
| | | | - Giuseppe Battiato
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via S. Sofia 64, 95125 Catania, Italy
| | - Cristiana Lucia Rita Lipari
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via S. Sofia 64, 95125 Catania, Italy
| | - Stefano Conti Nibali
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via S. Sofia 64, 95125 Catania, Italy
| | - Miriam Wissam Saab
- Department of Biomedical and Biotechnological Sciences, Division of Medical Biochemistry, University of Catania, Via S. Sofia 97, 95123 Catania, Italy
| | - Alessandra Pittalà
- Department of Biomedical and Biotechnological Sciences, Division of Medical Biochemistry, University of Catania, Via S. Sofia 97, 95123 Catania, Italy
| | - Angela Maria Amorini
- Department of Biomedical and Biotechnological Sciences, Division of Medical Biochemistry, University of Catania, Via S. Sofia 97, 95123 Catania, Italy
| | - Vito De Pinto
- we.MitoBiotech S.R.L., C.so Italia 174, 95125 Catania, Italy
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via S. Sofia 64, 95125 Catania, Italy
| | - Angela Messina
- Department of Biological, Geological and Environmental Sciences, University of Catania, Via S. Sofia 64, 95125 Catania, Italy
- we.MitoBiotech S.R.L., C.so Italia 174, 95125 Catania, Italy
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Hong SG, Shin J, Aldokhayyil M, Brown MD, Park JY. Mitochondrial and Metabolic Adaptations to Exercise-Induced Fluid Shear Stress in Endothelial Cells. Exerc Sport Sci Rev 2022; 50:145-155. [PMID: 35152237 PMCID: PMC9203873 DOI: 10.1249/jes.0000000000000289] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recent studies have greatly advanced our understanding of the central role of mitochondria on endothelial function. Here, we propose a hypothesis that unidirectional laminar (pulsatile) flow and disturbed laminar (oscillatory) flow may differentially modulate mitochondrial phenotypes in the context of their bioenergetic, signaling, and biosynthetic functions, providing novel insights into subcellular mechanisms underlying how exercise benefits the improvement of vascular health.
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Affiliation(s)
- Soon-Gook Hong
- Department of Kinesiology & Cardiovascular Research Center, Temple University, Philadelphia, PA
| | - Junchul Shin
- Department of Kinesiology & Cardiovascular Research Center, Temple University, Philadelphia, PA
| | | | | | - Joon-Young Park
- Department of Kinesiology & Cardiovascular Research Center, Temple University, Philadelphia, PA
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High-Resolution Respirometry Reveals MPP + Mitochondrial Toxicity Mechanism in a Cellular Model of Parkinson's Disease. Int J Mol Sci 2020; 21:ijms21217809. [PMID: 33105548 PMCID: PMC7659480 DOI: 10.3390/ijms21217809] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 10/19/2020] [Accepted: 10/20/2020] [Indexed: 12/21/2022] Open
Abstract
MPP+ is the active metabolite of MPTP, a molecule structurally similar to the herbicide Paraquat, known to injure the dopaminergic neurons of the nigrostriatal system in Parkinson’s disease models. Within the cells, MPP+ accumulates in mitochondria where it inhibits complex I of the electron transport chain, resulting in ATP depletion and neuronal impairment/death. So far, MPP+ is recognized as a valuable tool to mimic dopaminergic degeneration in various cell lines. However, despite a large number of studies, a detailed characterization of mitochondrial respiration in neuronal cells upon MPP+ treatment is still missing. By using high-resolution respirometry, we deeply investigated oxygen consumption related to each respiratory state in differentiated neuroblastoma cells exposed to the neurotoxin. Our results indicated the presence of extended mitochondrial damage at the inner membrane level, supported by increased LEAK respiration, and a drastic drop in oxygen flow devoted to ADP phosphorylation in respirometry measurements. Furthermore, prior to complex I inhibition, an enhancement of complex II activity was observed, suggesting the occurrence of some compensatory effect. Overall our findings provide a mechanistic insight on the mitochondrial toxicity mediated by MPP+, relevant for the standardization of studies that employ this neurotoxin as a disease model.
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Chan JYH, Chan SHH. Differential impacts of brain stem oxidative stress and nitrosative stress on sympathetic vasomotor tone. Pharmacol Ther 2019; 201:120-136. [PMID: 31153955 DOI: 10.1016/j.pharmthera.2019.05.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 05/24/2019] [Indexed: 02/07/2023]
Abstract
Based on work-done in the rostral ventrolateral medulla (RVLM), this review presents four lessons learnt from studying the differential impacts of oxidative stress and nitrosative stress on sympathetic vasomotor tone and their clinical and therapeutic implications. The first lesson is that an increase in sympathetic vasomotor tone because of augmented oxidative stress in the RVLM is responsible for the generation of neurogenic hypertension. On the other hand, a shift from oxidative stress to nitrosative stress in the RVLM underpins the succession of increase to decrease in sympathetic vasomotor tone during the progression towards brain stem death. The second lesson is that, by having different cellular sources, regulatory mechanisms on synthesis and degradation, kinetics of chemical reactions, and downstream signaling pathways, reactive oxygen species and reactive nitrogen species should not be regarded as a singular moiety. The third lesson is that well-defined differential roles of oxidative stress and nitrosative stress with distinct regulatory mechanisms in the RVLM during neurogenic hypertension and brain stem death clearly denote that they are not interchangeable phenomena with unified cellular actions. Special attention must be paid to their beneficial or detrimental roles under a specific disease or a particular time-window of that disease. The fourth lesson is that, to be successful, future antioxidant therapies against neurogenic hypertension must take into consideration the much more complicated picture than that presented in this review on the generation, maintenance, regulation or modulation of the sympathetic vasomotor tone. The identification that the progression towards brain stem death entails a shift from oxidative stress to nitrosative stress in the RVLM may open a new vista for therapeutic intervention to slow down this transition.
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Affiliation(s)
- Julie Y H Chan
- Institute for Translational Research in Biomedicine, Chang Gung Memorial Hospital, Kaohsiung, Taiwan, Republic of China
| | - Samuel H H Chan
- Institute for Translational Research in Biomedicine, Chang Gung Memorial Hospital, Kaohsiung, Taiwan, Republic of China.
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Mitochondrial Uncoupler Prodrug of 2,4-Dinitrophenol, MP201, Prevents Neuronal Damage and Preserves Vision in Experimental Optic Neuritis. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:7180632. [PMID: 28680531 PMCID: PMC5478871 DOI: 10.1155/2017/7180632] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 04/30/2017] [Indexed: 11/18/2022]
Abstract
The ability of novel mitochondrial uncoupler prodrug of 2,4-dinitrophenol (DNP), MP201, to prevent neuronal damage and preserve visual function in an experimental autoimmune encephalomyelitis (EAE) model of optic neuritis was evaluated. Optic nerve inflammation, demyelination, and axonal loss are prominent features of optic neuritis, an inflammatory optic neuropathy often associated with the central nervous system demyelinating disease multiple sclerosis. Currently, optic neuritis is frequently treated with high-dose corticosteroids, but treatment fails to prevent permanent neuronal damage and associated vision changes that occur as optic neuritis resolves, thus suggesting that additional therapies are required. MP201 administered orally, once per day, attenuated visual dysfunction, preserved retinal ganglion cells (RGCs), and reduced RGC axonal loss and demyelination in the optic nerves of EAE mice, with limited effects on inflammation. The prominent mild mitochondrial uncoupling properties of MP201, with slow elimination of DNP, may contribute to the neuroprotective effect by modulating the entire mitochondria's physiology directly. Results suggest that MP201 is a potential novel treatment for optic neuritis.
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Wu L, Guo X, Hartson SD, Davis MA, He H, Medeiros DM, Wang W, Clarke SL, Lucas EA, Smith BJ, von Lintig J, Lin D. Lack of β, β-carotene-9', 10'-oxygenase 2 leads to hepatic mitochondrial dysfunction and cellular oxidative stress in mice. Mol Nutr Food Res 2017; 61. [PMID: 27991717 DOI: 10.1002/mnfr.201600576] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 11/27/2016] [Accepted: 12/05/2016] [Indexed: 12/17/2022]
Abstract
SCOPE β,β-Carotene-9',10'-dioxygenase 2 (BCO2) is a carotenoid cleavage enzyme localized to the inner mitochondrial membrane in mammals. This study was aimed to assess the impact of genetic ablation of BCO2 on hepatic oxidative stress through mitochondrial function in mice. METHODS AND RESULTS Liver samples from 6-wk-old male BCO2-/- knockout (KO) and isogenic wild-type (WT) mice were subjected to proteomics and functional activity assays. Compared to the WT, KO mice consumed more food (by 18%) yet displayed significantly lower body weight (by 12%). Mitochondrial proteomic results demonstrated that loss of BCO2 was associated with quantitative changes of the mitochondrial proteome mainly shown by suppressed expression of enzymes and/or proteins involved in fatty acid β-oxidation, the tricarboxylic acid cycle, and the electron transport chain. The mitochondrial basal respiratory rate, proton leak, and electron transport chain complex II capacity were significantly elevated in the livers of KO compared to WT mice. Moreover, elevated reactive oxygen species and increased mitochondrial protein carbonylation were also demonstrated in liver of KO mice. CONCLUSIONS Loss of BCO2 induces mitochondrial hyperactivation, mitochondrial stress, and changes of the mitochondrial proteome, leading to mitochondrial energy insufficiency. BCO2 appears to be critical for proper hepatic mitochondrial function.
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Affiliation(s)
- Lei Wu
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, USA
| | - Xin Guo
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, USA
| | - Steven D Hartson
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK, USA
| | - Mary Abby Davis
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, USA
| | - Hui He
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, USA
| | - Denis M Medeiros
- Graduate School, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Weiqun Wang
- Department of Food, Nutrition, Dietetics, and Health, Kansas State University, Manhattan, KS, USA
| | - Stephen L Clarke
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, USA
| | - Edralin A Lucas
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, USA
| | - Brenda J Smith
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, USA
| | - Johannes von Lintig
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA
| | - Dingbo Lin
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, USA
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Manganese superoxide dismutase deficiency triggers mitochondrial uncoupling and the Warburg effect. Oncogene 2014; 34:4229-37. [PMID: 25362851 PMCID: PMC4859767 DOI: 10.1038/onc.2014.355] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 09/07/2014] [Accepted: 09/19/2014] [Indexed: 12/22/2022]
Abstract
Manganese superoxide dismutase (MnSOD) is a mitochondrially localized primary antioxidant enzyme, known to be essential for the survival of aerobic life and to have important roles in tumorigenesis. Here, we show that MnSOD deficiency in skin tissues of MnSOD-heterozygous knockout (Sod2(+/-)) mice leads to increased expresson of uncoupling proteins (UCPs). When MnSOD is deficient, superoxide radical and its resulting reactive oxygen species (ROS) activate ligand binding to peroxisome proliferator-activated receptor alpha (PPARα), suggesting that the activation of PPARα signaling is a major mechanism underlying MnSOD-dependent UCPs expression that consequently triggers the PI3K/Akt/mTOR pathway, leading to increased aerobic glycolysis. Knockdown of UCPs and mTOR suppresses lactate production and increases ATP levels, suggesting that UCPs contribute to increased glycolysis. These results highlight the existence of a free radical-mediated mechanism that activates mitochondria uncoupling to reduce ROS production, which precedes the glycolytic adaptation described as the Warburg Effect.
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Wu RM, Sun YY, Zhou TT, Zhu ZY, Zhuang JJ, Tang X, Chen J, Hu LH, Shen X. Arctigenin enhances swimming endurance of sedentary rats partially by regulation of antioxidant pathways. Acta Pharmacol Sin 2014; 35:1274-84. [PMID: 25152028 PMCID: PMC4186987 DOI: 10.1038/aps.2014.70] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 06/09/2014] [Indexed: 01/01/2023] Open
Abstract
AIM Arctigenin, a phenylpropanoid dibenzylbutyrolactone lignan found in traditional Chinese herbs, has been determined to exhibit a variety of pharmacological activities, including anti-tumor, anti-inflammation, neuroprotection, and endurance enhancement. In the present study, we investigated the antioxidation and anti-fatigue effects of arctigenin in rats. METHODS Rat L6 skeletal muscle cell line was exposed to H2O2 (700 μmol/L), and ROS level was assayed using DCFH-DA as a probe. Male SD rats were injected with arctigenin (15 mg·kg(-1)·d(-1), ip) for 6 weeks, and then the weight-loaded forced swimming test (WFST) was performed to evaluate their endurance. The levels of antioxidant-related genes in L6 cells and the skeletal muscles of rats were analyzed using real-time RT-PCR and Western blotting. RESULTS Incubation of L6 cells with arctigenin (1, 5, 20 μmol/L) dose-dependently decreased the H2O2-induced ROS production. WFST results demonstrated that chronic administration of arctigenin significantly enhanced the endurance of rats. Furthermore, molecular biology studies on L6 cells and skeletal muscles of the rats showed that arctigenin effectively increased the expression of the antioxidant-related genes, including superoxide dismutase (SOD), glutathione reductase (Gsr), glutathione peroxidase (GPX1), thioredoxin (Txn) and uncoupling protein 2 (UCP2), through regulation of two potential antioxidant pathways: AMPK/PGC-1α/PPARα in mitochondria and AMPK/p53/Nrf2 in the cell nucleus. CONCLUSION Arctigenin efficiently enhances rat swimming endurance by elevation of the antioxidant capacity of the skeletal muscles, which has thereby highlighted the potential of this natural product as an antioxidant in the treatment of fatigue and related diseases.
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Affiliation(s)
- Ruo-ming Wu
- School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Yan-yan Sun
- School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Ting-ting Zhou
- Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Zhi-yuan Zhu
- Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Jing-jing Zhuang
- School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Xuan Tang
- Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Jing Chen
- Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Li-hong Hu
- Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Xu Shen
- School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
- Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
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Protective effects of magnesium supplementation on metabolic energy derangements in lipopolysaccharide-induced cardiotoxicity in mice. Eur J Pharmacol 2012; 694:75-81. [PMID: 22939974 DOI: 10.1016/j.ejphar.2012.07.036] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2012] [Revised: 07/11/2012] [Accepted: 07/27/2012] [Indexed: 12/27/2022]
Abstract
Metabolic derangements and bioenergetic failure are major contributors to sepsis-induced multiple organ dysfunctions. Due to the well known role of magnesium (Mg) as a cofactor in many enzymatic reactions that involve energy creation and utilization, the present investigation was directed to estimate the cardioprotective effect of Mg supplementation in lipopolysaccharide (LPS)-induced metabolic energy changes in mice. Oral doses of Mg aspartate (20 or 40 mg/kg) were administered once daily for 7 day. Mice were then subjected to a single intraperitoneal injection of LPS (2 mg/kg). Plasma was separated 3 h after LPS injection for determination of creatine kinase-MB activity. Animals were then sacrificed and the hearts were separated for estimation of tissue thiobarbituric acid reactive substances, reduced glutathione, lactate, pyruvate, adenine nucleotides, creatine phosphate and cardiac Na(+),K(+)-ATPase activity. Finally, electron microscopic examination was performed to visualize the protective effects of Mg pretreatment on mitochondrial ultrastructure. In general, the higher dose of Mg was more effective than the lower dose in ameliorating creatine kinase-MB elevation and the state of oxidative stress, lactate accumulation, pyruvate reduction as well as preserving creatine phosphate, adenine nucleotides and Na(+),K(+)-ATPase activity. Moreover, the higher dose of Mg provided a significant cardioprotection against the mitochondrial ultrastructural changes. Mg therapy can afford a significant protection against metabolic energy derangements and mitochondrial ultrastructural changes induced by LPS cardiotoxicity in mice.
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Orhan N, Kucukali CI, Cakir U, Seker N, Aydin M. Genetic variants in nuclear-encoded mitochondrial proteins are associated with oxidative stress in obsessive compulsive disorders. J Psychiatr Res 2012; 46:212-8. [PMID: 22070905 DOI: 10.1016/j.jpsychires.2011.09.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Revised: 08/04/2011] [Accepted: 09/27/2011] [Indexed: 10/15/2022]
Abstract
Obsessive compulsive disorder is a common psychiatric disorder defined by the presence of obsessive thoughts and repetitive compulsive actions. The mutations or polymorphic variants in mitochondrial DNA-encoded genes or nuclear genes result in oxidative stress, which has recently been associated with various psychiatric disorders. In order to understand the association of mitochondrial disorders with oxidative stress in obsessive compulsive disorder, we examined genetic variants of manganese superoxide dismutase and uncouple-2 antioxidant genes and malondialdehyde and glutathione, markers of oxidative stress. The study sample comprised 104 patients with OCD and 110 healthy controls. For manganese superoxide dismutase, the frequencies of CT (Ala/Val) genotype (p < 0.01) in patients were significantly lower than those of controls. In contrast, CC (Ala/Ala) genotype was significantly more frequent in patients than controls (p < 0.05). For uncouple-2 I/D, the frequencies of ID genotype (p < 0.01) and I allele (p < 0.05) were lower in patients as compared with controls. In contrast, DD genotype was more prevalent in patients than controls (p < 0.01). While whole blood glutathione was significantly diminished (p < 0.0001), serum malondialdehyde was significantly elevated in patients compared with controls (p < 0.0001). Malondialdehyde levels were significantly elevated in subjects with DD genotype of UCP-2 I/D (p < 0.05) and CC genotype of manganese superoxide dismutase (p < 0.05) as compared with II or ID and TT or CT genotype, respectively. Malondialdehyde levels in patients carrying CC (p < 0.05) or CT (p < 0.05) genotype were significantly higher than those of carrying TT genotype. In conclusion, CC genotype of manganese superoxide dismutase or DD genotype of UCP-2 might result in mitochondrial disorders by increasing oxidative stress in obsessive compulsive disorders.
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Affiliation(s)
- Nurcan Orhan
- Department of Neuroscience, Institute of Experimental Medicine, Istanbul University, Istanbul, Turkey
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Ho PW, Ho JW, Liu HF, So DH, Tse ZH, Chan KH, Ramsden DB, Ho SL. Mitochondrial neuronal uncoupling proteins: a target for potential disease-modification in Parkinson's disease. Transl Neurodegener 2012; 1:3. [PMID: 23210978 PMCID: PMC3506996 DOI: 10.1186/2047-9158-1-3] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Accepted: 01/13/2012] [Indexed: 12/21/2022] Open
Abstract
This review gives a brief insight into the role of mitochondrial dysfunction and oxidative stress in the converging pathogenic processes involved in Parkinson's disease (PD). Mitochondria provide cellular energy in the form of ATP via oxidative phosphorylation, but as an integral part of this process, superoxides and other reactive oxygen species are also produced. Excessive free radical production contributes to oxidative stress. Cells have evolved to handle such stress via various endogenous anti-oxidant proteins. One such family of proteins is the mitochondrial uncoupling proteins (UCPs), which are anion carriers located in the mitochondrial inner membrane. There are five known homologues (UCP1 to 5), of which UCP4 and 5 are predominantly expressed in neural cells. In a series of previous publications, we have shown how these neuronal UCPs respond to 1-methyl-4-phenylpyridinium (MPP+; toxic metabolite of MPTP) and dopamine-induced toxicity to alleviate neuronal cell death by preserving ATP levels and mitochondrial membrane potential, and reducing oxidative stress. We also showed how their expression can be influenced by nuclear factor kappa-B (NF-κB) signaling pathway specifically in UCP4. Furthermore, we previously reported an interesting link between PD and metabolic processes through the protective effects of leptin (hormone produced by adipocytes) acting via UCP2 against MPP+-induced toxicity. There is increasing evidence that these endogenous neuronal UCPs can play a vital role to protect neurons against various pathogenic stresses including those associated with PD. Their expression, which can be induced, may well be a potential therapeutic target for various drugs to alleviate the harmful effects of pathogenic processes in PD and hence modify the progression of this disease.
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Affiliation(s)
- Philip Wl Ho
- Division of Neurology, Department of Medicine, University of Hong Kong, Pokfulam, Hong Kong SAR, China.
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Yang ZH, Miyahara H, Mori T, Doisaki N, Hatanaka A. Beneficial effects of dietary fish-oil-derived monounsaturated fatty acids on metabolic syndrome risk factors and insulin resistance in mice. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:7482-7489. [PMID: 21627145 DOI: 10.1021/jf201496h] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The aim of this study was to elucidate the effect of fish-oil-derived monounsaturated fatty acids (MUFAs) containing large amounts of C20:1 and C22:1 isomers on metabolic disorders in mice. Male C57BL/6J mice were fed a 32% lard diet (control) or a 27% lard plus 5% saury-oil-derived MUFA diet for 6 weeks. Dietary MUFA improved insulin resistance and alleviated metabolic syndrome risk factors by reducing blood glucose and lipids. These favorable changes may be attributed to an improved adipocytokine profile. MUFA ingestion resulted in favorable changes in mRNA expression of genes involved in glucose/lipid metabolism (SCD-1, CPT1a, UCPs, and CS) as well as inflammation (MAC1, MMP3, and SAA3) and alterations in fatty acid composition. Our data suggest that marine MUFA improved glucose/lipid homeostasis and hindered the development of metabolic syndrome in obese mice.
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Affiliation(s)
- Zhi-Hong Yang
- Central Research Laboratory, Tokyo Innovation Center, Nippon Suisan Kaisha, Ltd., Tokyo 192-0991, Japan.
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15
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Rodrigues AS, Lacerda B, Moreno AJM, Ramalho-Santos J. Proton leak modulation in testicular mitochondria affects reactive oxygen species production and lipid peroxidation. Cell Biochem Funct 2010; 28:224-31. [PMID: 20235330 DOI: 10.1002/cbf.1644] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Mitochondrial proton leak can account for almost 20% of oxygen consumption and it is generally accepted that this process contributes to basal metabolism. In order to clarify the role of basal proton leak in testicular mitochondria, we performed a comparative study with kidney and liver mitochondrial fractions. Proton leak stimulated by linoleic acid and inhibited by guanosine diphosphate (GDP) was detected, in a manner that was correlated with protein levels for uncoupling protein 2 (UCP2) in the three fractions. Modulation of proton leak had an effect on reactive oxygen species production as well as on lipid peroxidation, and this effect was also tissue-dependent. However, a possible role for the adenine nucleotide transporter (ANT) in testicular mitochondria proton leak could not be excluded. The modulation of proton leak appears as a possible and attractive target to control oxidative stress with implications for male gametogenesis.
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Affiliation(s)
- Ana Sofia Rodrigues
- Center for Neuroscience and Cell Biology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
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16
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Shabalina IG, Ost M, Petrovic N, Vrbacky M, Nedergaard J, Cannon B. Uncoupling protein-1 is not leaky. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:773-84. [PMID: 20399195 DOI: 10.1016/j.bbabio.2010.04.007] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2010] [Revised: 03/23/2010] [Accepted: 04/08/2010] [Indexed: 10/19/2022]
Abstract
The activity of uncoupling protein-1 (UCP1) is rate-limiting for nonshivering thermogenesis and diet-induced thermogenesis. Characteristically, this activity is inhibited by GDP experimentally and presumably mainly by cytosolic ATP within brown-fat cells. The issue as to whether UCP1 has a residual proton conductance even when fully saturated with GDP/ATP (as has recently been suggested) has not only scientific but also applied interest, since a residual proton conductance would make overexpressed UCP1 weight-reducing even without physiological/pharmacological activation. To examine this question, we have here established optimal conditions for studying the bioenergetics of wild-type and UCP1-/- brown-fat mitochondria, analysing UCP1-mediated differences in parallel preparations of brown-fat mitochondria from both genotypes. Comparing different substrates, we find that pyruvate (or palmitoyl-L-carnitine) shows the largest relative coupling by GDP. Comparing albumin concentrations, we find the range 0.1-0.6% optimal; higher concentrations are inhibitory. Comparing basic medium composition, we find 125 mM sucrose optimal; an ionic medium (50-100 mM KCl) functions for wild-type but is detrimental for UCP1-/- mitochondria. Using optimal conditions, we find no evidence for a residual proton conductance (not a higher post-GDP respiration, a lower membrane potential or an altered proton leak at highest common potential) with either pyruvate or glycerol-3-phosphate as substrates, nor by a 3-4-fold alteration of the amount of UCP1. We could demonstrate that certain experimental conditions, due to respiratoty inhibition, could lead to the suggestion that UCP1 possesses a residual proton conductance but find that under optimal conditions our experiments concur with implications from physiological observations that in the presence of inhibitory nucleotides, UCP1 is not leaky.
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Affiliation(s)
- Irina G Shabalina
- The Wenner-Gren Institute, Stockholm University, SE-106 91 Stockholm, Sweden
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17
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Chinopoulos C, Gerencser AA, Mandi M, Mathe K, Töröcsik B, Doczi J, Turiak L, Kiss G, Konràd C, Vajda S, Vereczki V, Oh RJ, Adam-Vizi V. Forward operation of adenine nucleotide translocase during F0F1-ATPase reversal: critical role of matrix substrate-level phosphorylation. FASEB J 2010; 24:2405-16. [PMID: 20207940 DOI: 10.1096/fj.09-149898] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In pathological conditions, F(0)F(1)-ATPase hydrolyzes ATP in an attempt to maintain mitochondrial membrane potential. Using thermodynamic assumptions and computer modeling, we established that mitochondrial membrane potential can be more negative than the reversal potential of the adenine nucleotide translocase (ANT) but more positive than that of the F(0)F(1)-ATPase. Experiments on isolated mitochondria demonstrated that, when the electron transport chain is compromised, the F(0)F(1)-ATPase reverses, and the membrane potential is maintained as long as matrix substrate-level phosphorylation is functional, without a concomitant reversal of the ANT. Consistently, no cytosolic ATP consumption was observed using plasmalemmal K(ATP) channels as cytosolic ATP biosensors in cultured neurons, in which their in situ mitochondria were compromised by respiratory chain inhibitors. This finding was further corroborated by quantitative measurements of mitochondrial membrane potential, oxygen consumption, and extracellular acidification rates, indicating nonreversal of ANT of compromised in situ neuronal and astrocytic mitochondria; and by bioluminescence ATP measurements in COS-7 cells transfected with cytosolic- or nuclear-targeted luciferases and treated with mitochondrial respiratory chain inhibitors in the presence of glycolytic plus mitochondrial vs. only mitochondrial substrates. Our findings imply the possibility of a rescue mechanism that is protecting against cytosolic/nuclear ATP depletion under pathological conditions involving impaired respiration. This mechanism comes into play when mitochondria respire on substrates that support matrix substrate-level phosphorylation.
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Affiliation(s)
- Christos Chinopoulos
- Department of Medical Biochemistry, Semmelweis University, Tuzolto St. 37-47, Room 4.521, Budapest, Hungary 1094.
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18
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Adiele RC, Stevens D, Kamunde C. Reciprocal enhancement of uptake and toxicity of cadmium and calcium in rainbow trout (Oncorhynchus mykiss) liver mitochondria. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2010; 96:319-327. [PMID: 20036780 DOI: 10.1016/j.aquatox.2009.11.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2009] [Revised: 11/10/2009] [Accepted: 11/25/2009] [Indexed: 05/28/2023]
Abstract
The interactive effects of cadmium (Cd) and calcium (Ca) on energy metabolism in rainbow trout liver mitochondria were studied to test the prediction that Ca would protect against Cd-induced mitochondrial liability. Isolated rainbow trout liver mitochondria were energized with malate and glutamate and exposed to increasing concentrations (5-100 microM) of Cd and Ca singly and in combination at 15 degrees C. Accumulation of Cd and Ca in the mitochondria and mitochondrial respiration (oxygen consumption) rates were measured. Additionally, un-energized mitochondria were incubated with low doses (1 microM) of Cd and Ca singly and in combination, with time-course measurements of cation accumulation/binding and oxygen consumption rates. In energized actively phosphorylating mitochondria, the uptake rates of both Cd and Ca were dose-dependent and enhanced when administered concurrently. Upon low-dose incubation, Cd accumulation was rapid and peaked in 5 min, while no appreciable uptake of Ca occurred. Functionally, the resting (state 4, ADP-limited) respiration rate was not affected in the dose-response exposure, but it decreased remarkably on low-dose incubation. Adenosine diphosphate (ADP)-stimulated respiration (state 3) rate was impaired dose-dependently with maximal inhibitions (at the highest dose, 100 microM) of 32, 64 and 73% for Ca, Cd, and combined exposures, respectively. The combined effects of Ca and Cd suggested synergistic (more than additive) action and partial additivity of effects at low and higher doses of the two cations, respectively. Moreover, on a molar basis, Cd was twice as toxic as Ca to rainbow trout liver mitochondria and when combined, approximately 90% of the effects were attributable to Cd. The coupling efficiency, as measured by respiratory control ratio (RCR) and phosphorylation efficiency, measured as ADP/O ratio, both decreased as the exposure dosage and duration increased. In addition, Cd and Ca exposure decreased mitochondrial proton leak (state 4+ respiration) rates on prolonged exposure possibly by inhibiting processes that generate mitochondrial membrane potential, the force that drives proton leak. Overall these data suggest that the widely accepted theme that Ca and Cd are competitive antagonists does not hold for mitochondrial effects and that Cd and Ca cooperate to impair oxidative phosphorylation in rainbow trout liver mitochondria.
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Affiliation(s)
- Reginald C Adiele
- Department of Biomedical Sciences, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, PE C1A4P3, Canada
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19
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Chan SHH, Wu CA, Wu KLH, Ho YH, Chang AYW, Chan JYH. Transcriptional upregulation of mitochondrial uncoupling protein 2 protects against oxidative stress-associated neurogenic hypertension. Circ Res 2009; 105:886-96. [PMID: 19762685 DOI: 10.1161/circresaha.109.199018] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
RATIONALE Mitochondrial uncoupling proteins (UCPs) belong to a superfamily of mitochondrial anion transporters that uncouple ATP synthesis from oxidative phosphorylation and mitigates mitochondrial reactive oxygen species production. OBJECTIVE We assessed the hypothesis that UCP2 participates in central cardiovascular regulation by maintaining reactive oxygen species homeostasis in the rostral ventrolateral medulla (RVLM), where sympathetic premotor neurons that maintain vasomotor tone located. We also elucidated the molecular mechanisms that underlie transcriptional upregulation of UCP2 in response to oxidative stress in RVLM. METHODS AND RESULTS In Sprague-Dawley rats, transcriptional upregulation of UCP2 in RVLM by rosiglitazone, an activator of its transcription factor peroxisome proliferator-activated receptor (PPAR)gamma, reduced mitochondrial hydrogen peroxide level in RVLM and systemic arterial pressure. Oxidative stress induced by microinjection of angiotensin II into RVLM augmented UCP2 mRNA or protein expression in RVLM, which was antagonized by comicroinjection of NADPH oxidase inhibitor (diphenyleneiodonium chloride), superoxide dismutase mimetic (tempol), or p38 mitogen-activated protein kinase inhibitor (SB203580) but not by extracellular signal-regulated kinase 1/2 inhibitor (U0126). Angiotensin II also induced phosphorylation of the PPARgamma coactivator, PPARgamma coactivator (PGC)-1alpha, and an increase in formation of PGC-1alpha/PPARgamma complexes in a p38 mitogen-activated protein kinase-dependent manner. Intracerebroventricular infusion of angiotensin II promoted an increase in mitochondrial hydrogen peroxide production in RVLM and chronic pressor response, which was potentiated by gene knockdown of UCP2 but blunted by rosiglitazone. CONCLUSIONS These results suggest that transcriptional upregulation of mitochondrial UCP2 in response to an elevation in superoxide plays an active role in feedback regulation of reactive oxygen species production in RVLM and neurogenic hypertension associated with chronic oxidative stress.
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Affiliation(s)
- Samuel H H Chan
- Center for Translational Research in Biomedical Sciences, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Republic of China
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20
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Liu JS, Yang M, Sun RY, Wang DH. Adaptive thermogenesis in Brandt's vole (Lasiopodomys brandti) during cold and warm acclimation. J Therm Biol 2009. [DOI: 10.1016/j.jtherbio.2008.11.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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21
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Barreiro E, Garcia-Martínez C, Mas S, Ametller E, Gea J, Argilés JM, Busquets S, López-Soriano FJ. UCP3 overexpression neutralizes oxidative stress rather than nitrosative stress in mouse myotubes. FEBS Lett 2008; 583:350-6. [PMID: 19101552 DOI: 10.1016/j.febslet.2008.12.023] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Revised: 12/07/2008] [Accepted: 12/10/2008] [Indexed: 01/11/2023]
Abstract
The deleterious effects of oxidants on proteins may be modified by overexpression of uncoupling protein 3 (UCP3) in skeletal muscle cells exposed to hyperoxia or H(2)O(2). UCP3 overexpression significantly attenuated the increase in protein carbonylation in response to hyperoxia and H(2)O(2) exposures. However, antioxidant enzyme content and activity (superoxide dismutases, peroxiredoxins, glutathione peroxidase-I, and catalase) were reduced or not modified in UCP3-overexpressing myotubes exposed to oxidants. Protein nitration increased in UCP3-overexpressing cells exposed to hyperoxia, but not to H(2)O(2). We conclude that protein oxidation rather than nitration is neutralized by UPC3 overexpression in mouse myotubes exposed to abundant reactive oxygen species.
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Affiliation(s)
- Esther Barreiro
- Muscle and Respiratory System Research Unit-Pneumology Department, IMIM-Hospital del Mar, Centro de Investigación en Red de Enfermedades Respiratorias (CibeRes), CEXS, Universitat Pompeu Fabra, Barcelona Biomedical Research Park, Barcelona, Spain
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22
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van Bilsen M, van Nieuwenhoven FA, van der Vusse GJ. Metabolic remodelling of the failing heart: beneficial or detrimental? Cardiovasc Res 2008; 81:420-8. [PMID: 18854380 DOI: 10.1093/cvr/cvn282] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The failing heart is characterized by alterations in energy metabolism, including mitochondrial dysfunction and a reduction in fatty acid (FA) oxidation rate, which is partially compensated by an increase in glucose utilization. Together, these changes lead to an impaired capacity to convert chemical energy into mechanical work. This has led to the concept that supporting cardiac energy conversion through metabolic interventions provides an important adjuvant therapy for heart failure. The potential success of such a therapy depends on whether the shift from FA towards glucose utilization should be considered beneficial or detrimental, a question still incompletely resolved. In this review, the current status of the literature is evaluated and possible causes of observed discrepancies are discussed. It is cautiously concluded that for the failing heart, from a therapeutic point of view, it is preferable to further stimulate glucose oxidation rather than to normalize substrate metabolism by stimulating FA utilization. Whether this also applies to the pre-stages of cardiac failure remains to be established.
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Affiliation(s)
- Marc van Bilsen
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands.
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23
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Sud N, Wells SM, Sharma S, Wiseman DA, Wilham J, Black SM. Asymmetric dimethylarginine inhibits HSP90 activity in pulmonary arterial endothelial cells: role of mitochondrial dysfunction. Am J Physiol Cell Physiol 2008; 294:C1407-18. [PMID: 18385287 DOI: 10.1152/ajpcell.00384.2007] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Increased asymmetric dimethylarginine (ADMA) levels have been implicated in the pathogenesis of a number of conditions affecting the cardiovascular system. However, the mechanism(s) by which ADMA exerts its effect has not been adequately elucidated. Thus the purpose of this study was to determine the effect of increased ADMA on nitric oxide (NO) signaling and to begin to elucidate the mechanism by which ADMA acts. Our initial data demonstrated that ADMA increased NO synthase (NOS) uncoupling in both recombinant human endothelial NO synthase (eNOS) and pulmonary arterial endothelial cells (PAEC). Furthermore, we found that this endothelial NOS (eNOS) uncoupling increased 3-nitrotyrosine levels preferentially in the mitochondria of PAEC due to a redistribution of eNOS from the plasma membrane to the mitochondria. This increase in nitration in the mitochondria was found to induce mitochondrial dysfunction as determined by increased mitochondrial-derived reactive oxygen species and decreased generation of ATP. Finally, we found that the decrease in ATP resulted in a reduction in the chaperone activity of HSP90 resulting in a decrease in its interaction with eNOS. In conclusion increased levels of ADMA causes mitochondrial dysfunction and a loss of heat shock protein-90 chaperone activity secondary to an uncoupling of eNOS. Mitochondrial dysfunction may be an understudied component of the endothelial dysfunction associated with various cardiovascular disease states.
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Affiliation(s)
- Neetu Sud
- Vascular Biology Center, Medical College of Georgia, Augusta, GA 30912, USA
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24
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Sharma S, Sud N, Wiseman DA, Carter AL, Kumar S, Hou Y, Rau T, Wilham J, Harmon C, Oishi P, Fineman JR, Black SM. Altered carnitine homeostasis is associated with decreased mitochondrial function and altered nitric oxide signaling in lambs with pulmonary hypertension. Am J Physiol Lung Cell Mol Physiol 2007; 294:L46-56. [PMID: 18024721 DOI: 10.1152/ajplung.00247.2007] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Utilizing aortopulmonary vascular graft placement in the fetal lamb, we have developed a model (shunt) of pulmonary hypertension that mimics congenital heart disease with increased pulmonary blood flow. Our previous studies have identified a progressive development of endothelial dysfunction in shunt lambs that is dependent, at least in part, on decreased nitric oxide (NO) signaling. The purpose of this study was to evaluate the possible role of a disruption in carnitine metabolism in shunt lambs and to determine the effect on NO signaling. Our data indicate that at 2 wk of age, shunt lambs have significantly reduced expression (P < 0.05) of the key enzymes in carnitine metabolism: carnitine palmitoyltransferases 1 and 2 as well as carnitine acetyltransferase (CrAT). In addition, we found that CrAT activity was inhibited due to increased nitration. Furthermore, free carnitine levels were significantly decreased whereas acylcarnitine levels were significantly higher in shunt lambs (P < 0.05). We also found that alterations in carnitine metabolism resulted in mitochondrial dysfunction, since shunt lambs had significantly decreased pyruvate, increased lactate, and a reduced pyruvate/lactate ratio. In pulmonary arterial endothelial cells cultured from juvenile lambs, we found that mild uncoupling of the mitochondria led to a decrease in cellular ATP levels and a reduction in both endothelial NO synthase-heat shock protein 90 (eNOS-HSP90) interactions and NO signaling. Similarly, in shunt lambs we found a loss of eNOS-HSP90 interactions that correlated with a progressive decrease in NO signaling. Our data suggest that mitochondrial dysfunction may play a role in the development of endothelial dysfunction and pulmonary hypertension and increased pulmonary blood flow.
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Affiliation(s)
- Shruti Sharma
- Program in Pulmonary Disease, Vascular Biology Center, Medical College of Georgia, Augusta, GA 30912, USA
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25
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Fink BD, Herlein JA, Almind K, Cinti S, Kahn CR, Sivitz WI. Mitochondrial proton leak in obesity-resistant and obesity-prone mice. Am J Physiol Regul Integr Comp Physiol 2007; 293:R1773-80. [PMID: 17761507 DOI: 10.1152/ajpregu.00478.2007] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We quantified uncoupling proteins (UCPs) in molar amounts and assessed proton conductance in mitochondria isolated from interscapular brown adipose tissue (IBAT) and hindlimb muscle [known from prior work to contain ectopic brown adipose tissue (BAT) interspersed between muscle fibers] of obesity-resistant 129S6/SvEvTac (129) and obesity-prone C57BL/6 (B6) mice under conditions of low (LF) and high-fat (HF) feeding. With usual feeding, IBAT mitochondrial UCP1 content and proton conductance were greater in 129 mice than B6. However, with HF feeding, UCP1 and proton conductance increased more in B6 mice. Moreover, with HF feeding GDP-inhibitable proton conductance, specific for UCP1, equaled that seen in the 129 strain. UCP1 expression was substantial in mitochondria from hindlimb muscle tissue (ectopic BAT) of 129 mice as opposed to B6 but did not increase with HF feeding in either strain. As expected, muscle UCP3 expression increased with HF feeding in both strains but did not differ by strain. Moreover, the proton conductance of mitochondria isolated from hindlimb muscle tissue did not differ by strain or diet. Our data uncover a response to weight gain in obesity-prone (compared to resistant) mice unrecognized in prior studies that examined only UCP1 mRNA. Obesity-prone mice have the capacity to increase both IBAT UCP1 protein and mitochondrial proton conductance as much or more than obesity-resistant mice. But, this is only achieved only at a higher body mass and, therefore, may be adaptive rather than preventative. Neither obesity-prone nor resistant mice respond to HF feeding by expressing more UCP1 in ectopic BAT within muscle tissue.
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Affiliation(s)
- Brian D Fink
- University of Iowa, Iowa City Veterans Affairs Medical Center, Iowa City, IA 52242, USA
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26
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Van De Parre T, Martinet W, Verheye S, De Meyer G. Uncoupling protein 2-mediated thermogenesis in vulnerable atherosclerotic plaques. EUROINTERVENTION 2007; 3:275-9. [DOI: 10.4244/eijv3i2a47] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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27
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28
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Beck V, Jabůrek M, Demina T, Rupprecht A, Porter RK, Jezek P, Pohl EE. Polyunsaturated fatty acids activate human uncoupling proteins 1 and 2 in planar lipid bilayers. FASEB J 2007; 21:1137-44. [PMID: 17242157 DOI: 10.1096/fj.06-7489com] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Uncoupling proteins 1 (UCP1) and 2 (UCP2) belong to the family of mitochondrial anion transporters and share 59% sequence identity with each other. Whereas UCP1 was shown to be responsible for the rapid production of heat in brown adipose tissue, the primary function and transport properties of ubiquitously expressed UCP2 are controversially discussed. Here, for the first time, the activation pattern of the recombinant human UCP2 in comparison to the recombinant human UCP1 are studied using a well-defined system of planar lipid bilayers. It is shown that despite apparently different physiological functions, hUCP2 exhibited its protonophoric function similar to hUCP1--exclusively in the presence of long-chain fatty acids (FA). The calculated hUCP2 transport rate of 4.5 s(-1) is the same order of magnitude, as shown previously for UCP1. It leads to the conclusion that the differences in the activity of both proteins in living mitochondria are based exclusively on their different expression level. Both proteins are activated much more effectively by polyunsaturated than by saturated FA. The proton and total membrane conductances increased in the range palmitic < oleic < eicosatrienoic < linoleic < retinoic < arachidonic acids. The higher uncoupling protein (UCP)-dependent conductance in the presence of polyunsaturated FA is explained on the basis of the FA cycling hypothesis.
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Affiliation(s)
- Valeri Beck
- Institute of Cell Biology and Neurobiology, Charité Universitätsmedizin, Charitéplatz 1, 10117 Berlin, Germany
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29
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Ho PWL, Chu ACY, Kwok KHH, Kung MHW, Ramsden DB, Ho SL. Knockdown of uncoupling protein-5 in neuronal SH-SY5Y cells: Effects on MPP+-induced mitochondrial membrane depolarization, ATP deficiency, and oxidative cytotoxicity. J Neurosci Res 2007; 84:1358-66. [PMID: 16941493 DOI: 10.1002/jnr.21034] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Uncoupling proteins (UCPs) uncouple oxidative phosphorylation from ATP synthesis by dissipating proton gradient across mitochondrial inner membrane. The physiological role of neuronal specific UCP5 is unknown. We explored the effects of reduced UCP5 expression on mitochondrial membrane potential (MMP), oxidative stress, ATP levels, and cell viability, under normal and MPP+-induced cytotoxic conditions, in human catecholaminergic SH-SY5Y cells. UCP5 expression was reduced by 56% by siRNA, compared to scrambled-siRNA controls. UCP5 knockdown induced apoptosis but did not affect basal levels of ATP, oxidative stress and MMP in the cells under normal conditions. However, UCP5 knockdown increased MPP+-induced cytotoxicity by 15% and oxidative stress levels by 40%, and partially restored MPP+-induced mitochondrial depolarization by 57%. UCP2 and UCP4 expression were unaffected by UCP5 knockdown. Exacerbation of cytotoxicity, oxidative stress and modification of MMP with reduced UCP5 expression in the face of MPP+ toxicity suggest that UCP5 might be physiologically important in the pathology of oxidative stress-induced neurodegeneration.
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Affiliation(s)
- Philip Wing-Lok Ho
- Division of Neurology, University Department of Medicine, University of Hong Kong, Hong Kong, People's Republic of China
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30
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Shabalina I, Kramarova T, Nedergaard J, Cannon B. Carboxyatractyloside effects on brown-fat mitochondria imply that the adenine nucleotide translocator isoforms ANT1 and ANT2 may be responsible for basal and fatty-acid-induced uncoupling respectively. Biochem J 2006; 399:405-14. [PMID: 16831128 PMCID: PMC1615905 DOI: 10.1042/bj20060706] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In brown-fat mitochondria, fatty acids induce thermogenic uncoupling through activation of UCP1 (uncoupling protein 1). However, even in brown-fat mitochondria from UCP1-/- mice, fatty-acid-induced uncoupling exists. In the present investigation, we used the inhibitor CAtr (carboxyatractyloside) to examine the involvement of the ANT (adenine nucleotide translocator) in the mediation of this UCP1-independent fatty-acid-induced uncoupling in brown-fat mitochondria. We found that the contribution of ANT to fatty-acid-induced uncoupling in UCP1-/- brown-fat mitochondria was minimal (whereas it was responsible for nearly half the fatty-acid-induced uncoupling in liver mitochondria). As compared with liver mitochondria, brown-fat mitochondria exhibit a relatively high (UCP1-independent) basal respiration ('proton leak'). Unexpectedly, a large fraction of this high basal respiration was sensitive to CAtr, whereas in liver mitochondria, basal respiration was CAtr-insensitive. Total ANT protein levels were similar in brown-fat mitochondria from wild-type mice and in liver mitochondria, but the level was increased in brown-fat mitochondria from UCP1-/- mice. However, in liver, only Ant2 mRNA was found, whereas in brown adipose tissue, Ant1 and Ant2 mRNA levels were equal. The data are therefore compatible with a tentative model in which the ANT2 isoform mediates fatty-acid-induced uncoupling, whereas the ANT1 isoform may mediate a significant part of the high basal proton leak in brown-fat mitochondria.
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MESH Headings
- Adenine Nucleotide Translocator 1/antagonists & inhibitors
- Adenine Nucleotide Translocator 1/biosynthesis
- Adenine Nucleotide Translocator 1/genetics
- Adenine Nucleotide Translocator 1/physiology
- Adenine Nucleotide Translocator 2/antagonists & inhibitors
- Adenine Nucleotide Translocator 2/biosynthesis
- Adenine Nucleotide Translocator 2/genetics
- Adenine Nucleotide Translocator 2/physiology
- Adipose Tissue, Brown/drug effects
- Adipose Tissue, Brown/metabolism
- Animals
- Atractyloside/analogs & derivatives
- Atractyloside/pharmacology
- Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone/pharmacology
- Cell Respiration/drug effects
- Crosses, Genetic
- Fatty Acids/metabolism
- Fatty Acids/pharmacology
- Guanosine Diphosphate/pharmacology
- Ion Channels/deficiency
- Ion Channels/genetics
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mitochondria/drug effects
- Mitochondria/metabolism
- Mitochondria, Liver/drug effects
- Mitochondria, Liver/metabolism
- Mitochondrial Proteins/deficiency
- Mitochondrial Proteins/genetics
- Models, Biological
- Oleic Acid/pharmacology
- Organ Specificity
- Oxygen Consumption/drug effects
- Palmitates/pharmacology
- Protons
- Pyruvic Acid/pharmacology
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Thermogenesis/drug effects
- Thermogenesis/physiology
- Uncoupling Agents/pharmacology
- Uncoupling Protein 1
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Affiliation(s)
- Irina G. Shabalina
- The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Tatiana V. Kramarova
- The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Jan Nedergaard
- The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Barbara Cannon
- The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden
- To whom correspondence should be addressed (email )
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31
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Nübel T, Ricquier D. Respiration under control of uncoupling proteins: Clinical perspective. HORMONE RESEARCH 2006; 65:300-10. [PMID: 16641553 DOI: 10.1159/000092847] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Indexed: 11/19/2022]
Abstract
The term 'uncoupling protein' was originally used for the mitochondrial membrane protein UCP1, which is uniquely present in mitochondria of brown adipocytes, thermogenic cells that regulate body temperature in small rodents, hibernators and mammalian newborns. In these cells, UCP1 acts as a proton carrier activated by free fatty acids and creates a shunt between complexes of the respiratory chain and ATP-synthase resulting in a futile proton cycling and dissipation of oxidation energy as heat. Recent identification of new homologues to UCP1 expressed in brown and white adipose tissue, muscle, brain and other tissues together with the hypothesis that these novel uncoupling proteins (UCPs) may regulate thermogenesis and/or fatty acid metabolism and furthermore may protect against free radical oxygen species production have generated considerable optimism for rapid advances in the identification of new targets for pharmacological management of complex pathological syndromes such as obesity, type 2 diabetes or chronic inflammatory diseases. However, since the physiological and biochemical roles of the novel UCPs are not yet clear, the main challenge today consists first of all in providing mechanistic explanation for their functions in cellular physiology. This lively awaited information may be the basis for potential pharmacological targeting of the UCPs in future.
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Affiliation(s)
- T Nübel
- Centre National de la Recherche Scientifique, Unit 9078, Faculty of Medicine René Descartes Paris 5, Paris, France
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32
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Thermal sensitivity of uncoupling protein expression in polar and temperate fish. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2006; 1:365-74. [PMID: 20483268 DOI: 10.1016/j.cbd.2006.08.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2006] [Revised: 08/06/2006] [Accepted: 08/07/2006] [Indexed: 11/21/2022]
Abstract
Uncoupling proteins (UCP), capable of increasing proton leakage across the inner mitochondrial membrane, may play a role in the temperature-dependent setting of energy turnover in animals (and their mitochondria). Therefore, the genes and expression of fish UCP were investigated in the Antarctic eelpout Pachycara brachycephalum and a temperate confamilial species, the common eelpout Zoarces viviparus. UCP full-length cDNA was amplified from liver and muscle using RT-PCR and rapid amplification of cDNA ends (RACE). The fish UCP mRNA consists of 1906 bp in P. brachycephalum and of 1876 bp in Z. viviparus. Both zoarcid sequences contain open reading frames of 939 bp, encoding 313 amino acids, with 98% and 99% identity, respectively. Protein sequences of zoarcid UCP are closest related to fish and mammalian UCP2. For analysis of temperature-dependent expression common eelpouts were cold-acclimated from 10 degrees C to 2 degrees C and Antarctic eelpouts were warm-acclimated from 0 degrees C to 5 degrees C. Identical cDNA probes for both species were developed to investigate fish UCP mRNA expression, and protein expression levels were detected by Western Blot in the enriched membrane fraction. During cold-acclimation in Z. viviparus, mRNA levels increased by a factor up to 2.0, protein levels increased up to 1.5, in line with mitochondrial proliferation during cold-acclimation. Despite decreased mitochondrial protein content, in Antarctic eelpout UCP levels rose upon warm acclimation by a factor up to 2.0 (mRNA) and 1.6 (protein), respectively. Besides the ongoing discussion of UCP function in vertebrates, the data are indicative of a significant role of fish UCP in thermal adaptation of fish mitochondria.
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33
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Guo P, Nishiyama A, Rahman M, Nagai Y, Noma T, Namba T, Ishizawa M, Murakami K, Miyatake A, Kimura S, Mizushige K, Abe Y, Ohmori K, Kohno M. Contribution of reactive oxygen species to the pathogenesis of left ventricular failure in Dahl salt-sensitive hypertensive rats: effects of angiotensin II blockade. J Hypertens 2006; 24:1097-104. [PMID: 16685210 DOI: 10.1097/01.hjh.0000226200.73065.5d] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE We investigated the contribution of reduced nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase-dependent reactive oxygen species (ROS) generation to the pathogenesis of diastolic heart failure (DHF) in Dahl salt-sensitive (DS) hypertensive rats, with the aim of testing our hypothesis that the cardioprotective effects of angiotensin II (Ang II) blockade are provided by the suppression of this pathway. METHODS DS rats were maintained on high (H: 8.0% NaCl) or low (L: 0.3% NaCl) salt diets from age 7 to 17 weeks. DS/H rats were also treated with candesartan cilexetil (10 mg/kg per day, orally) or a superoxide dismutase mimetic, tempol (3 mmol/l in drinking water) from age 7 to 17 weeks. RESULTS DS/H rats represented hypertension, left ventricular (LV) relaxation abnormality and myocardial stiffening with preserved systolic heart function. As compared with DS/L rats, DS/H rats showed higher levels of transforming growth factor-beta (TGF-beta), connective tissue growth factor (CTGF), p22phox and gp91phox mRNA expression, NADPH oxidase activity and thiobarbituric acid-reactive substance (TBARS) contents in LV tissues. Gene expression of uncoupling protein-2 (UCP-2), an inner mitochondrial membrane proton transporter, was also 2.8 +/- 0.5-fold higher. In DS/H rats, treatment with candesartan did not alter blood pressure, but resulted in a marked improvement of the hemodynamic deterioration; these therapeutic effects were accompanied by decreases in myocardial NADPH oxidase activity, TBARS contents and the expression of TGF-beta, CTGF, p22phox, gp91phox and UCP-2. Similar therapeutic effects were provided by treatment with tempol in DS/H rats. CONCLUSIONS Our data suggest that NADPH oxidase-mediated ROS production contributes to the pathogenesis of DHF in DS hypertensive rats, and that the cardioprotective effects of AngII blockade are, at least partially, mediated through the suppression of this pathway.
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Affiliation(s)
- Peng Guo
- Department of Cardiorenal and Cerebrovascular Medicine, Kagawa University Medical School, Kita-gun, Kagawa, Japan
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34
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Schaeffer PJ, Villarin JJ, Pierotti DJ, Kelly DP, Lindstedt SL. Cost of transport is increased after cold exposure in Monodelphis domestica: training for inefficiency. ACTA ACUST UNITED AC 2006; 208:3159-67. [PMID: 16081613 DOI: 10.1242/jeb.01703] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Monodelphis domestica (Didelphidae: Marsupialia) lacks brown adipose tissue and thus relies on skeletal muscle as its primary thermogenic organ. Following cold exposure, the aerobic capacity of skeletal muscle in these animals is greatly increased. We investigated the effects of this plastic response to thermogenesis on locomotion and muscle mechanics. In cold-exposed animals, cost of transport was 15% higher than in controls but was unaffected by exercise training. Twitch kinetics in isolated semitendinosus muscles of cold-exposed animals were characteristic of slow-oxidative fiber types. Both time-to-peak tension and half-relaxation time were longer and maximal shortening velocity was slower following cold exposure compared to either thermoneutral controls or exercise-trained animals. Further, muscles from the cold-exposed animals had greater fatigue resistance than either control or exercise-trained animals, indicating greater oxidative capacity. Finally, we identified an uncoupling protein 3 homologue, whose gene expression was upregulated in skeletal muscle of cold-exposed Monodelphis domestica. Cold exposure provided a potent stimulus for muscle plasticity, driving a fast-to-slow transition more effectively than exercise training. However, linked to the dramatic shift in muscle properties is an equally dramatic increase in whole animal muscle energetics during locomotion, suggesting an uncoupled state, or 'training for inefficiency'.
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Affiliation(s)
- Paul J Schaeffer
- Department of Biological Sciences, Physiology and Functional Morphology Group, Northern Arizona University, Flagstaff, AZ 86011, USA.
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35
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Busquets S, Garcia-Martínez C, Olivan M, Barreiro E, López-Soriano FJ, Argilés JM. Overexpression of UCP3 in both murine and human myotubes is linked with the activation of proteolytic systems: A role in muscle wasting? Biochim Biophys Acta Gen Subj 2006; 1760:253-8. [PMID: 16337086 DOI: 10.1016/j.bbagen.2005.10.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2005] [Revised: 10/20/2005] [Accepted: 10/23/2005] [Indexed: 12/01/2022]
Abstract
Overexpression of the UCP3 gene in both murine and human myotube cell cultures leads to a significant activation of the different proteolytic systems involved in muscle myofibrillar protein breakdown. Thus, lysosomal (cathepsin B) and non-lysosomal (m-calpain and ubiquitin-proteasome) mRNA content was significantly increased in the different cell culture systems used. Interestingly, the overexpression of the UCP3 gene was not associated with any changes in apoptosis. Although the function of the UCP3 protein is not completely understood (uncoupling, oxidative stress), these results suggest a possible relation between these main mechanisms involved in muscle wasting during cancer.
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Affiliation(s)
- Sílvia Busquets
- Departament de Bioquímica i Biologia Molecular, Facultat de Biologia, Universitat de Barcelona, Diagonal 645, 08028-Barcelona, Spain
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36
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Hirabara SM, Silveira LR, Alberici LC, Leandro CVG, Lambertucci RH, Polimeno GC, Cury Boaventura MF, Procopio J, Vercesi AE, Curi R. Acute effect of fatty acids on metabolism and mitochondrial coupling in skeletal muscle. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2005; 1757:57-66. [PMID: 16375848 DOI: 10.1016/j.bbabio.2005.11.007] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2005] [Revised: 10/30/2005] [Accepted: 11/15/2005] [Indexed: 01/11/2023]
Abstract
Acute effects of free fatty acids (FFA) were investigated on: (1) glucose oxidation, and UCP-2 and -3 mRNA and protein levels in 1 h incubated rat soleus and extensor digitorium longus (EDL) muscles, (2) mitochondrial membrane potential in cultured skeletal muscle cells, (3) respiratory activity and transmembrane electrical potential in mitochondria isolated from rat skeletal muscle, and (4) oxygen consumption by anesthetized rats. Long-chain FFA increased both basal and insulin-stimulated glucose oxidation in incubated rat soleus and EDL muscles and reduced mitochondrial membrane potential in C2C12 myotubes and rat skeletal muscle cells. Caprylic, palmitic, oleic, and linoleic acid increased O(2) consumption and decreased electrical membrane potential in isolated mitochondria from rat skeletal muscles. FFA did not alter UCP-2 and -3 mRNA and protein levels in rat soleus and EDL muscles. Palmitic acid increased oxygen consumption by anesthetized rats. These results suggest that long-chain FFA acutely lead to mitochondrial uncoupling in skeletal muscle.
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MESH Headings
- Animals
- Carrier Proteins/genetics
- Carrier Proteins/metabolism
- Cells, Cultured
- Coenzyme A/metabolism
- Fatty Acids/pharmacology
- Glucose/metabolism
- In Vitro Techniques
- Insulin/pharmacology
- Ion Channels
- Linoleic Acid/pharmacology
- Membrane Potentials/drug effects
- Membrane Transport Proteins/genetics
- Membrane Transport Proteins/metabolism
- Mitochondria, Muscle/drug effects
- Mitochondria, Muscle/metabolism
- Mitochondrial Membranes/drug effects
- Mitochondrial Proteins/genetics
- Mitochondrial Proteins/metabolism
- Muscle Cells/drug effects
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/metabolism
- Muscle, Skeletal/cytology
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Oleic Acid/pharmacology
- Oxygen Consumption/drug effects
- Palmitic Acid/pharmacology
- RNA, Messenger/analysis
- RNA, Messenger/metabolism
- Rats
- Uncoupling Protein 2
- Uncoupling Protein 3
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Affiliation(s)
- Sandro M Hirabara
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Cidade Universitária, Av. Professor Lineu Prestes, 1524 Butantã, São Paulo, SP 05508-900, Brazil
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37
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Ho PWL, Chan DYL, Kwok KHH, Chu ACY, Ho JWM, Kung MHW, Ramsden DB, Ho SL. Methyl-4-phenylpyridinium ion modulates expression of mitochondrial uncoupling proteins 2, 4, and 5 in catecholaminergic (SK-N-SH) cells. J Neurosci Res 2005; 81:261-8. [PMID: 15948157 DOI: 10.1002/jnr.20569] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Methyl-4-phenylpyridinium ion (MPP(+)), a specific dopaminergic neurotoxin, inhibits mitochondrial complex I activity, generates reactive oxygen species (ROS), reduces ATP production, and induces cell death. We explored changes in expression of uncoupling proteins (UCPs 2, 4, and 5) following MPP(+)-induced toxicity in SK-N-SH cells over 72 hr at the transcriptional (quantification of mRNA by real-time RT-PCR) and translational (Western analysis) levels. UCP5 mRNA and protein were markedly up-regulated (1 mM MPP(+) at 72 hr caused a twofold increase, P < 0.01), as was UCP4 mRNA, albeit to a much lesser extent. Surprisingly, UCP2 mRNA levels decreased at 24 hr (P < 0.05) but thereafter significantly increased to greater than control levels at 72 hr (P < 0.05), although UCP2 protein levels were decreased throughout (1 mM MPP(+) at 72 hr caused a reduction of 50%, P < 0.01). The increase in ROS production may be attenuated by UCP4 and UCP5 up-regulation. The consequence of decreased UCP2 levels is unclear, although this may represent an adaptive response to declines in ATP levels, the subsequent increase in mRNA being a response to further increases in oxidative stress.
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Affiliation(s)
- Philip Wing-Lok Ho
- Division of Neurology, University Department of Medicine, University of Hong Kong, Hong Kong, People's Republic of China
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38
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Esteves TC, Brand MD. The reactions catalysed by the mitochondrial uncoupling proteins UCP2 and UCP3. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2005; 1709:35-44. [PMID: 16005426 DOI: 10.1016/j.bbabio.2005.06.002] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2005] [Revised: 06/06/2005] [Accepted: 06/08/2005] [Indexed: 11/23/2022]
Abstract
The mitochondrial uncoupling proteins UCP2 and UCP3 may be important in attenuating mitochondrial production of reactive oxygen species, in insulin signalling (UCP2), and perhaps in thermogenesis and other processes. To understand their physiological roles, it is necessary to know what reactions they are able to catalyse. We critically examine the evidence for proton transport and anion transport by UCP2 and UCP3. There is good evidence that they increase mitochondrial proton conductance when activated by superoxide, reactive oxygen species derivatives such as hydroxynonenal, and other alkenals or their analogues. However, they do not catalyse proton leak in the absence of such acute activation. They can also catalyse export of fatty acid and other anions, although the relationship of anion transport to proton transport remains controversial.
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Affiliation(s)
- Telma C Esteves
- MRC Dunn Human Nutrition Unit, Hills Road, Cambridge CB2 2XY, UK
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39
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Abstract
AIMS Mitochondria are responsible for meeting the majority of the energetic demand of most tissues. They also play a major role in regulating cell survival. These dual roles of mitochondria place them at the centre of many pathologies leading to tissue degeneration and disruption of energy balance. The prominent role of mitochondria in ageing and disease has led to a tremendous growth in mitochondrial research at the cellular and molecular level. We describe below a new non-invasive approach to measure mitochondrial function that will bridge the gap between our understanding of mitochondrial function in vitro and that in the intact organism. METHODS AND RESULTS This approach uses optical and magnetic resonance spectroscopy to measure in vivo O2 consumption and ATP synthesis rates, respectively, from skeletal muscle. These values lead to a quantitative assessment of the mitochondrial ATP/O2 or P/O. The P/O represents the efficiency of coupling between phosphorylation and oxygen consumption in the mitochondria, which is a measure of mitochondrial dysfunction. CONCLUSIONS This work represents a significant advance in research on the role of mitochondria in degenerative disease and ageing because it allows a quantitative measure of mitochondrial pathology in vivo. The non-invasive nature of this approach also enables repeated measures of mitochondrial function on the same individual, thereby making this a potentially useful diagnostic technique. The results from this work have led to insights into the coupling of ATP synthesis to oxidation and the regulation of oxidative phosphorylation by intracellular PO2.
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Affiliation(s)
- D J Marcinek
- Department of Radiology, University of Washington Medical Center, Seattle, WA 98195, USA
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40
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Carroll AM, Haines LR, Pearson TW, Fallon PG, Walsh CM, Brennan CM, Breen EP, Porter RK. Identification of a functioning mitochondrial uncoupling protein 1 in thymus. J Biol Chem 2005; 280:15534-43. [PMID: 15695816 DOI: 10.1074/jbc.m413315200] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
We present evidence that rat and mouse thymi contain mitochondrial uncoupling protein (UCP 1). Reverse transcriptase-PCR detected RNA transcripts for UCP 1 in whole thymus and in thymocytes. Furthermore, using antibodies to UCP 1 the protein was also detected in mitochondria isolated from whole thymus and thymocytes but not in thymus mitochondria from UCP 1 knock-out mice. Evidence for functional UCP 1 in thymus mitochondria was obtained by a comparative analysis with the kinetics of GDP binding in mitochondria from brown adipose tissue. Both tissues showed equivalent B(max) and K(D) values. In addition, a large component of the nonphosphorylating oxygen consumption by thymus mitochondria was inhibited by GDP and subsequently stimulated by addition of nanomolar concentrations of palmitate. UCP 1 was purified from thymus mitochondria by hydroxyapatite chromatography. The isolated protein was identified by peptide mass mapping and tandem mass spectrometry by using MALDI-TOF and LC-MS/MS, respectively. We conclude that the thymus contains a functioning UCP 1 that has the capacity to regulate metabolic flux and production of reactive oxygen-containing molecules in the thymus.
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Affiliation(s)
- Audrey M Carroll
- Department of Biochemistry, Trinity College Dublin, Dublin 2, Ireland
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41
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Abstract
The single-electron chemistry of mitochondrial oxidative phosphorylation (ox-phos) by default generates reactive oxygen species (ROS). These ROS have roles in both physiologic cell signaling and numerous pathologic situations. One factor that has the potential to regulate ROS generation is the mild uncoupling of ox-phos, i.e., proton (H(+)) leak across the mitochondrial inner membrane. Proton leak has been shown to decrease ROS generation, whereas ROS have been shown to induce H(+) leak, and this suggests the existence of a feedback loop between ROS and H(+) leak. Interestingly, although H(+) leak is detrimental to ATP synthesis, it has been shown to be cytoprotective in several models of ischemic injury. Herein the molecular basis of both ROS generation and H(+) leak will be reviewed and the consequences of their interaction for mitochondrial function discussed.
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Affiliation(s)
- Paul S Brookes
- Department of Anesthesiology, University of Rochester, Medical Center Box 604, 601 Elmwood Avenue, Rochester, NY 14642, USA.
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42
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Ramsey JJ, Harper ME, Humble SJ, Koomson EK, Ram JJ, Bevilacqua L, Hagopian K. Influence of mitochondrial membrane fatty acid composition on proton leak and H2O2 production in liver. Comp Biochem Physiol B Biochem Mol Biol 2005; 140:99-108. [PMID: 15621515 DOI: 10.1016/j.cbpc.2004.09.016] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2004] [Revised: 09/17/2004] [Accepted: 09/19/2004] [Indexed: 11/16/2022]
Abstract
Mitochondrial membrane fatty acid composition has been proposed to play a role in determining mitochondrial proton leak rate. The purpose of this study was to determine if feeding rats diets with different fatty acid sources produces changes in liver proton leak and H(2)O(2) production. Six-month-old male FBNF(1) rats were fed diets with a primary fat source of either corn or fish oil for a 6-month period. As expected, diet manipulations produced substantial differences in mitochondrial fatty acid composition. These changes were most striking for 20:4n6 and 22:6n3. However, proton leak and phosphorylation kinetics as well as lipid and protein oxidative damage were not different (P > 0.10) between fish and corn oil groups. Metabolic control analysis, however, did show that control of both substrate oxidation and phosphorylation was shifted away from substrate oxidation reactions to increased control by phosphorylation reactions in fish versus corn oil groups. Increased mitochondrial H(2)O(2) production was observed in corn versus fish oil-fed rats when mitochondria were respiring on succinate alone or on either succinate or pyruvate/malate in the presence of antimycin A. These results show that mitochondrial H(2)O(2) production and the regulation of oxidative phosphorylation are altered in liver mitochondria from rats consuming diets with either fish or corn oil as the primary lipid source.
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Affiliation(s)
- Jon J Ramsey
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
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43
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Kitahara T, Li-Korotky HS, Balaban CD. Regulation of mitochondrial uncoupling proteins in mouse inner ear ganglion cells in response to systemic kanamycin challenge. Neuroscience 2005; 135:639-53. [PMID: 16111824 DOI: 10.1016/j.neuroscience.2005.06.056] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2005] [Revised: 05/27/2005] [Accepted: 06/15/2005] [Indexed: 10/25/2022]
Abstract
Mitochondrial uncoupling proteins are a proton transporter family involved in regulation mitochondrial superoxide and ATP production. Uncoupling proteins are expressed by rat spiral ganglion and vestibular ganglion cells [Hear Res 196 (2004) 39]. This study tests the hypothesis that uncoupling protein expression is up-regulated in response to the reactive oxygen species challenge imposed by kanamycin and antioxidant (2,3-dihydroxybenzoate) treatment in mice. In control C57BL/6, CBA/J and BALB/c mice, mRNA for uncoupling protein 1, uncoupling protein 2, uncoupling protein 3, Slc25a27 (uncoupling protein 4) and Slc25a14 (uncoupling protein 5/BMCP1) was expressed in the spiral and vestibular ganglia. After kanamycin-treatment (700 mg/kg twice daily for 14 days s.c.), uncoupling protein 2 and uncoupling protein 3 mRNA expression increased significantly in spiral and vestibular ganglia and kidney, but was unaffected in cerebral cortex. Significant Slc25a27 (uncoupling protein 4) mRNA up-regulation was also observed in spiral and vestibular ganglia, but not in kidney or cerebral cortex. These effects were blocked by simultaneous administration of kanamycin and 2,3-dihydroxybenzoate (300 mg/kg twice daily for 14 days s.c.). Western immunoblotting and immunohistochemistry confirmed the uncoupling protein 2 and uncoupling protein 3 up-regulation in inner ear. Finally, 2,3-dihydroxybenzoate treatment alone produced an upregulation of uncoupling protein 1 mRNA in the spiral ganglion, vestibular ganglion and cerebral cortex, but not the kidney. Uncoupling protein 2 and uncoupling protein 3 upregulation in the kidney and inner ear ganglia likely reflects their general role as a feedback pathway to reduce mitochondrial superoxide generation. Slc25a27 (uncoupling protein 4) upregulation in the inner ear ganglia, by contrast, is likely to be a secondary response to kanamycin-induced hair cell death. We propose that increased uncoupling protein 2, uncoupling protein 3 and Slc25a27 expression has several neuroprotective effects via reduction in mitochondrial superoxide generation and local thermogenesis, including: (1) reducing mean ROS load to prevent apoptosis, (2) increasing signal-to-noise characteristics of intracellular ROS signaling pathways (e.g. lipoxygenases, growth factor and transcription factors), (3) heat-related alteration of enzyme kinetics and (4) promotion of cell depolarization (activation of heat-gated ion channels).
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Affiliation(s)
- T Kitahara
- Department of Otolaryngology, University of Pittsburgh School of Medicine, 107 Eye and Ear Institute, Pittsburgh, PA 15213, USA
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44
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Kitahara T, Li HS, Balaban CD. Localization of the mitochondrial uncoupling protein family in the rat inner ear. Hear Res 2004; 196:39-48. [PMID: 15464300 DOI: 10.1016/j.heares.2004.02.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2003] [Accepted: 02/12/2004] [Indexed: 11/26/2022]
Abstract
Uncoupling proteins (UCPs) are a proton transporter family located in the mitochondrial inner membrane. The molecular expression and activity of UCPs in brown adipose tissue and skeletal muscle are regulated by factors as diverse as chronic overeating and cold exposure, suggesting roles in energy expenditure and heat production. Although UCP2, UCP4 and brain mitochondrial carrier protein-1 (BMCP-1, i.e. UCP5) mRNAs are expressed in the central nervous system, their central function is unknown. This study presents the first evidence on localization and quantitative expression of UCPs in the rat inner ear by real-time PCR and immunohistochemistry. Real-time PCR studies revealed that UCP2 mRNA was expressed in the vestibular and spiral ganglia more abundantly than any other UCP. Neocortex, by contrast, contained UCP2 and UCP4 equally. Notably, UCP3 and UCP4 mRNAs were expressed in inner ear ganglia, but brain UCP3 mRNA expression level was undetectable by simple PCR. Immunohistochemical studies confirmed that both UCP2- and UCP3-like immunoreactivities were detected in vestibular and spiral ganglion cells and co-localized with a mitochondrial marker, MitoFluorGreen. According to previous reports, UCP2 and UCP3 are thermogenic in yeast and brain UCP2 has been suggested to modulate pre- and post-synaptic events by axonal thermogenesis. It has also been reported recently that UCP2 and UCP3 responses to superoxide application may be an antioxidant protective mechanism. Therefore, it is suggested that mitochondrial UCPs (UCP2, UCP3, UCP4) may play both a protective role against oxidative damage and a thermal signaling role in the eighth nerve.
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Affiliation(s)
- Tadashi Kitahara
- Department of Otolaryngology, University of Pittsburgh School of Medicine, 107 Eye and Ear Institute, 203 Lothrop Street, Pittsburgh, PA 15123, USA
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45
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Figueras M, Busquets S, Carbó N, Barreiro E, Almendro V, Argilés JM, López-Soriano FJ. Interleukin-15 is able to suppress the increased DNA fragmentation associated with muscle wasting in tumour-bearing rats. FEBS Lett 2004; 569:201-6. [PMID: 15225634 DOI: 10.1016/j.febslet.2004.05.066] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2004] [Revised: 05/28/2004] [Accepted: 05/28/2004] [Indexed: 12/20/2022]
Abstract
Administration of interleukin-15 (IL-15) to rats bearing the Yoshida AH-130 ascites hepatoma (a tumour that induces an important cachectic response) resulted in a significant reduction of muscle wasting, both measured as muscle weight and as protein content of different types of skeletal muscle. In addition, the administration of the cytokine completely reversed the increased DNA fragmentation observed in skeletal muscle of tumour-bearing animals. Concerning the mechanism(s) involved in the anti-apoptotic effects of IL-15 on skeletal muscle, the administration of the cytokine resulted in a considerable decrease in both R1 (43%) and R2 (64%) TNF-alpha receptors (TNFRs), and therefore it may be suggested that IL-15 decreases apoptosis by affecting TNF-alpha signalling. Formation of NO could be the signalling event associated with the activation of apoptosis in muscle of tumour-bearing rats; indeed, administration of IL-15 decreased the inducible nitric oxide synthase protein levels by 73%, suggesting that NO formation and muscle apoptosis during tumour growth are related. In conclusion, IL-15 seems to be able to reduce/suppress protein loss and apoptosis related to muscle wasting during cancer cachexia in experimental animals.
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MESH Headings
- Animals
- Antigens, CD/genetics
- Apoptosis/drug effects
- Base Sequence
- Body Weight/drug effects
- Cachexia/etiology
- Cachexia/pathology
- Cachexia/prevention & control
- Carcinoma, Hepatocellular/physiopathology
- DNA Primers
- Disease Models, Animal
- Gene Expression Regulation, Neoplastic/drug effects
- Humans
- Interleukin-15/therapeutic use
- Male
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/pathology
- Organ Size/drug effects
- RNA, Messenger/genetics
- Rats
- Rats, Wistar
- Receptors, Tumor Necrosis Factor/genetics
- Receptors, Tumor Necrosis Factor, Type I
- Receptors, Tumor Necrosis Factor, Type II
- Recombinant Proteins/therapeutic use
- Sarcoma, Experimental/physiopathology
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Affiliation(s)
- Maite Figueras
- Departament de Bioquímica i Biologia Molecular, Universitat de Barcelona, Barcelona, Spain
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46
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Herrera B, Murillo MM, Alvarez-Barrientos A, Beltrán J, Fernández M, Fabregat I. Source of early reactive oxygen species in the apoptosis induced by transforming growth factor-beta in fetal rat hepatocytes. Free Radic Biol Med 2004; 36:16-26. [PMID: 14732287 DOI: 10.1016/j.freeradbiomed.2003.09.020] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2003] [Revised: 09/17/2003] [Accepted: 09/17/2003] [Indexed: 11/25/2022]
Abstract
Transforming growth factor-beta (TGF-beta) induces an oxidative stress process in hepatocytes that mediates its apoptotic activity. To determine the cellular source of the early reactive oxygen species (ROS) generated by fetal rat hepatocytes in response to TGF-beta, we used inhibitors that block different ROS-producing systems. Diphenyleneiodonium, which inhibits NADPH oxidase and other flavoproteins, completely blocked the increase in ROS induced by TGF-beta, coincidently with an impairment of caspase-3 activation and cell death. Rotenone, an inhibitor of the NADH dehydrogenase in mitochondrial complex I, attenuated, but did not completely inhibit, ROS-production, caspase activation, and cell death mediated by TGF-beta. No significant protection was observed with inhibitors of other ROS-producing systems, such as cytochrome P450 (metyrapone), cyclooxygenase (indomethacin), and xanthine oxidase (allopurinol). Additional experiments have indicated that two different mechanisms could be involved in the early ROS production by TGF-beta. First, an inducible (cycloheximide-inhibited) NADPH oxidase-like system could account for the extramitochondrial production of ROS. Second, TGF-beta could increase ROS by a rapid downregulation of antioxidant genes. In particular, intramitochondrial ROS would increase by depletion of MnSOD. Finally, glutathione depletion is a late event and it would be more the consequence than the cause of the increase in ROS induced by TGF-beta.
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Affiliation(s)
- Blanca Herrera
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad Complutense de Madrid, 28040 Madrid, Spain
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47
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Berry S. Endosymbiosis and the design of eukaryotic electron transport. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2003; 1606:57-72. [PMID: 14507427 DOI: 10.1016/s0005-2728(03)00084-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The bioenergetic organelles of eukaryotic cells, mitochondria and chloroplasts, are derived from endosymbiotic bacteria. Their electron transport chains (ETCs) resemble those of free-living bacteria, but were tailored for energy transformation within the host cell. Parallel evolutionary processes in mitochondria and chloroplasts include reductive as well as expansive events: On one hand, bacterial complexes were lost in eukaryotes with a concomitant loss of metabolic flexibility. On the other hand, new subunits have been added to the remaining bacterial complexes, new complexes have been introduced, and elaborate folding patterns of the thylakoid and mitochondrial inner membranes have emerged. Some bacterial pathways were reinvented independently by eukaryotes, such as parallel routes for quinol oxidation or the use of various anaerobic electron acceptors. Multicellular organization and ontogenetic cycles in eukaryotes gave rise to further modifications of the bioenergetic organelles. Besides mitochondria and chloroplasts, eukaryotes have ETCs in other membranes, such as the plasma membrane (PM) redox system, or the cytochrome P450 (CYP) system. These systems have fewer complexes and simpler branching patterns than those in energy-transforming organelles, and they are often adapted to non-bioenergetic functions such as detoxification or cellular defense.
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Affiliation(s)
- Stephan Berry
- Plant Biochemistry, Faculty of Biology, Ruhr-University-Bochum, Universitätsstr. 150, D-44780 Bochum, Germany.
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48
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Grav HJ, Tronstad KJ, Gudbrandsen OA, Berge K, Fladmark KE, Martinsen TC, Waldum H, Wergedahl H, Berge RK. Changed energy state and increased mitochondrial beta-oxidation rate in liver of rats associated with lowered proton electrochemical potential and stimulated uncoupling protein 2 (UCP-2) expression: evidence for peroxisome proliferator-activated receptor-alpha independent induction of UCP-2 expression. J Biol Chem 2003; 278:30525-33. [PMID: 12756242 DOI: 10.1074/jbc.m303382200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Lowering of plasma triglyceride levels by hypolipidemic agents is caused by a shift in the liver cellular metabolism, which become poised toward peroxisome proliferator-activated receptor (PPAR) alpha-regulated fatty acid catabolism in mitochondria. After dietary treatment of rats with the hypolipidemic, modified fatty acid, tetradecylthioacetic acid (TTA), the energy state parameters of the liver were altered at the tissue, cell, and mitochondrial levels. Thus, the hepatic phosphate potential, energy charge, and respiratory control coefficients were lowered, whereas rates of oxygen uptake, oxidation of pyridine nucleotide redox pairs, beta-oxidation, and ketogenesis were elevated. Moderate uncoupling of mitochondria from TTA-treated rats was confirmed, as the proton electrochemical potential (Delta(p)) was 15% lower than controls. The change affected the Delta(Psi) component only, leaving the (Delta)pH component unaltered, suggesting that TTA causes induction of electrogenic ion transport rather than electrophoretic fatty acid activity. TTA treatment induced expression of hepatic uncoupling protein 2 (UCP-2) in rats as well as in wild type and PPARalpha-deficient mice, accompanied by a decreased double bond index of the mitochondrial membrane lipids. However, changes of mitochondrial fatty acid composition did not seem to be related to the effects on mitochondrial energy conductance. As TTA activates PPARdelta, we discuss how this subtype might compensate for deficiency of PPARalpha. The overall changes recorded were moderate, making it likely that liver metabolism can maintain its function within the confines of its physiological regulatory framework where challenged by a hypolipemic agent such as TTA, as well as others.
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Affiliation(s)
- Hans J Grav
- Institute for Nutrition Research, University of Oslo, N-0316 Oslo, Norway
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49
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Parra D, González A, Martínez JA, Labayen I, Díez N. In vivo assessment of the mitochondrial response to caloric restriction in obese women by the 2-keto[1-C]isocaproate breath test. Metabolism 2003; 52:463-7. [PMID: 12701059 DOI: 10.1053/meta.2003.50075] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The 2-keto[1-(13)C]isocaproate breath test has been proposed as a tool to detect mitochondrial dysfunction in alcoholic liver disease. The aim of this study was to evaluate if the 2-keto[1-(13)C]isocaproate breath test could detect in vivo dynamic changes on mitochondrial activity due to caloric restriction in obese women. Fifteen obese women (body mass index [BMI] > 30 kg/m(2)) participated in the study at baseline. Ten of these women agreed to participate on a diet program to induce body weight loss. Fifteen lean women (BMI < 25 kg/m(2)) were included as a control group. The breath test was performed by the oral administration of the tracer measuring (13)CO(2) enrichment in breath before and after ingestion using isotope ratio mass spectrometry. Body composition, resting energy expenditure, and plasma levels of insulin and leptin were measured. There were no relationships observed between the 2-keto[1-(13)C]isocaproate breath test and the plasma insulin (before diet: P =.863; after diet: P =.879), or leptin (before diet: P =.500; after diet: P =.637). In obese women before treatment, kilograms of fat free mass (P =.108), resting energy expenditure adjusted for body composition (P =.312), and the 2-keto[1-(13)C]isocaproate breath test (P =.205) were similar in comparison to lean women. However, 2-keto[1-(13)C]isocaproate oxidation tended to increase after dieting and was significantly higher than in controls (P =.015). These data suggest that the 2-keto[1-(13)C]isocaproate breath test reflected the adaptive modifications in mitochondrial oxidation in response to caloric restriction in obese women.
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Affiliation(s)
- Dolores Parra
- Department of Clinical Biochemistry, Clínica Universitaria de Navarra, Pamplona. Spain
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50
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Larrarte E, Margareto J, Novo FJ, Marti A, Alfredo Martínez J. UCP1 muscle gene transfer and mitochondrial proton leak mediated thermogenesis. Arch Biochem Biophys 2002; 404:166-71. [PMID: 12127082 DOI: 10.1016/s0003-9861(02)00201-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Mitochondrial uncoupling protein 1 (UCP1) mediates the thermogenic transport of protons through the inner mitochondrial membrane. This proton leak uncouples respiration from ATP synthesis. The current study assessed the possible contribution of UCP1 muscle gene transfer to impair mitochondrial respiration in a tissue lacking UCP1 gene expression. Rats received an intramuscular injection of plasmid pXC1 containing UCP1 cDNA in the right tibialis muscles, while left tibialis muscles were injected with empty plasmid as control. Ten days after DNA injection, mitochondria from tibialis anterior muscles were isolated and analyzed. UCP1 gene transfer resulted in protein expression as analyzed by inmunoblotting. Mitochondria isolated from UCP1-injected muscles showed a significant increase in state 2 and state 4 oxygen consumption rates and a decreased respiration control ratio in comparison to mitochondria from control muscles. Furthermore, UCP1-containing mitochondria had a lower membrane potential in those states (2 and 4) when compared with control mitochondria. Our results revealed that UCP1 muscle gene transfer is associated with an induced mitochondrial proton leak, which could contribute to increase energy expenditure.
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Affiliation(s)
- Eider Larrarte
- Department of Physiology and Nutrition, University of Navarra, 31008 Pamplona, Spain
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