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Prá M, Ferreira GK, de Mello AH, Schraiber RDB, Cardoso LC, Souza LDR, da Rosa N, Fortunato JJ, Rezin GT. Single dose and repeated administrations of liraglutide alter energy metabolism in the brains of young and adult rats. Biochem Cell Biol 2016; 94:451-458. [PMID: 27563837 DOI: 10.1139/bcb-2016-0016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Liraglutide is a human glucagon-like peptide-1 (GLP-1) analogue that was recently approved to treat obesity in some countries. Considering that liraglutide effects on brain energy metabolism are little known, we evaluated the effects of liraglutide on the energy metabolism. Animals received a single or daily injection of saline or liraglutide during 7 days (25, 50, 100, or 300 μg/kg i.p.). Twenty-four hours after the single or last injection, the rats were euthanized and the hypothalamus, prefrontal cortex, cerebellum, hippocampus, striatum, and posterior cortex were isolated. Our results demonstrated that a single dose of liraglutide in young rats increased the activity of complexes and inhibited creatine kinase activity. Repeated administrations of liraglutide in young rats reduced the activity of complexes and activated creatine kinase activity. In adult rats, a single dose of liraglutide reduced the activity of complex I and creatine kinase and increased the activity of complexes II and IV. Repeated administrations of liraglutide in adult rats increased the activity of complexes I and IV and reduced the activity of complex II and creatine kinase. We concluded that liraglutide may interfere in energy metabolism, because analysis of different times of administrations, concentrations, and level of brain development leads to divergent results.
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Affiliation(s)
- Morgana Prá
- a Laboratory of Clinical and Experimental Pathophysiology, Postgraduate Program in Health Sciences, University of Southern Santa Catarina, Tubarão, 88704-900 SC, Brazil
| | - Gabriela Kozuchovski Ferreira
- b Laboratory Pharmacology and Pathophysiology of Skin, Department of Pharmacology, Federal University of Paraná, Curitiba, 81531-980 PR, Brazil
| | - Aline Haas de Mello
- a Laboratory of Clinical and Experimental Pathophysiology, Postgraduate Program in Health Sciences, University of Southern Santa Catarina, Tubarão, 88704-900 SC, Brazil
| | - Rosiane de Bona Schraiber
- a Laboratory of Clinical and Experimental Pathophysiology, Postgraduate Program in Health Sciences, University of Southern Santa Catarina, Tubarão, 88704-900 SC, Brazil
| | - Larissa Colonetti Cardoso
- a Laboratory of Clinical and Experimental Pathophysiology, Postgraduate Program in Health Sciences, University of Southern Santa Catarina, Tubarão, 88704-900 SC, Brazil
| | - Luana da Rosa Souza
- a Laboratory of Clinical and Experimental Pathophysiology, Postgraduate Program in Health Sciences, University of Southern Santa Catarina, Tubarão, 88704-900 SC, Brazil
| | - Naiana da Rosa
- c Laboratory of Neuroscience, Postgraduate Program in Health Sciences, University of Southern Santa Catarina, Tubarão, 88704-900 SC, Brazil
| | - Jucélia Jeremias Fortunato
- c Laboratory of Neuroscience, Postgraduate Program in Health Sciences, University of Southern Santa Catarina, Tubarão, 88704-900 SC, Brazil
| | - Gislaine Tezza Rezin
- a Laboratory of Clinical and Experimental Pathophysiology, Postgraduate Program in Health Sciences, University of Southern Santa Catarina, Tubarão, 88704-900 SC, Brazil
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Chinese Herbs Interfering with Cancer Reprogramming Metabolism. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2016; 2016:9282813. [PMID: 27242914 PMCID: PMC4875995 DOI: 10.1155/2016/9282813] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Accepted: 02/03/2016] [Indexed: 12/11/2022]
Abstract
Emerging evidence promotes a reassessment of metabolic reprogramming regulation in cancer research. Although there exists a long history of Chinese herbs applied in cancer treatment, few reports have addressed the effects of Chinese herbal components on metabolic reprogramming, which is a central cancer hallmark involved in the slowing or prevention of chemoresistance in cancer cells. In this review, we have focused on four core elements altered by metabolic reprogramming in cancer cells. These include glucose transport, glycolysis, mitochondrial oxidative phosphorylation, and fatty acid synthesis. With this focus, we have summarized recent advances in metabolic reprogramming of cancer cells in response to specific Chinese herbal components. We propose that exploring Chinese herbal interference in cancer metabolic reprogramming might identify new therapeutic targets for cancer and more ways in which to approach metabolism-related diseases.
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Ferguson MA, Sutton RM, Karlsson M, Sjövall F, Becker LB, Berg RA, Margulies SS, Kilbaugh TJ. Increased platelet mitochondrial respiration after cardiac arrest and resuscitation as a potential peripheral biosignature of cerebral bioenergetic dysfunction. J Bioenerg Biomembr 2016; 48:269-79. [PMID: 27020568 DOI: 10.1007/s10863-016-9657-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 03/15/2016] [Indexed: 02/02/2023]
Abstract
UNLABELLED Cardiac arrest (CA) results in a sepsis-like syndrome with activation of the innate immune system and increased mitochondrial bioenergetics. OBJECTIVE To determine if platelet mitochondrial respiration increases following CA in a porcine pediatric model of asphyxia-associated ventricular fibrillation (VF) CA, and if this readily obtained biomarker is associated with decreased brain mitochondrial respiration. CA protocol: 7 min of asphyxia, followed by VF, protocolized titration of compression depth to systolic blood pressure of 90 mmHg and vasopressor administration to a coronary perfusion pressure greater than 20 mmHg. PRIMARY OUTCOME platelet integrated mitochondrial electron transport system (ETS) function evaluated pre- and post-CA/ROSC four hours after return of spontaneous circulation (ROSC). Secondary outcome: correlation of platelet mitochondrial bioenergetics to cerebral bioenergetic function. Platelet maximal oxidative phosphorylation (OXPHOSCI+CII), P < 0.02, and maximal respiratory capacity (ETSCI+CII), P < 0.04, were both significantly increased compared to pre-arrest values. This was primarily due to a significant increase in succinate-supported respiration through Complex II (OXPHOSCII, P < 0.02 and ETSCII, P < 0.03). Higher respiration was not due to uncoupling, as the LEAKCI + CII respiration (mitochondrial respiration independent of ATP-production) was unchanged after CA/ROSC. Larger increases in platelet mitochondrial respiratory control ratio (RCR) compared to pre-CA RCR were significantly correlated with lower RCRs in the cortex (P < 0.03) and hippocampus (P < 0.04) compared to sham respiration. Platelet mitochondrial respiration is significantly increased four hours after ROSC. Future studies will identify mechanistic relationships between this serum biomarker and altered cerebral bioenergetics function following cardiac arrest.
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Affiliation(s)
- Michael A Ferguson
- Anesthesiology and Critical Care Medicine, The Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, 34th & Civic Center Blvd., Philadelphia, PA, 19104, USA
| | - Robert M Sutton
- Anesthesiology and Critical Care Medicine, The Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, 34th & Civic Center Blvd., Philadelphia, PA, 19104, USA
| | - Michael Karlsson
- Mitochondrial Medicine, Department of Clinical Sciences, Lund University, BMC A13, SE-221 84, Lund, Sweden
| | - Fredrik Sjövall
- Mitochondrial Medicine, Department of Clinical Sciences, Lund University, BMC A13, SE-221 84, Lund, Sweden
| | - Lance B Becker
- Department of Emergency Medicine, Perelman School of Medicine at the University of Pennsylvania, The Hospital of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA, 19104, USA
| | - Robert A Berg
- Anesthesiology and Critical Care Medicine, The Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, 34th & Civic Center Blvd., Philadelphia, PA, 19104, USA
| | - Susan S Margulies
- School of Engineering and Applied Science, Department of Bioengineering, University of Pennsylvania, 210 South 33rd Street, Philadelphia, PA, 19104, USA
| | - Todd J Kilbaugh
- Anesthesiology and Critical Care Medicine, The Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, 34th & Civic Center Blvd., Philadelphia, PA, 19104, USA.
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Structural and functional characterization of phosphomimetic mutants of cytochrome c at threonine 28 and serine 47. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:387-95. [PMID: 26806033 DOI: 10.1016/j.bbabio.2016.01.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Revised: 01/15/2016] [Accepted: 01/20/2016] [Indexed: 12/31/2022]
Abstract
Protein function is frequently modulated by post-translational modifications of specific residues. Cytochrome c, in particular, is phosphorylated in vivo at threonine 28 and serine 47. However, the effect of such modifications on the physiological functions of cytochrome c - namely, the transfer of electrons in the respiratory electron transport chain and the triggering of programmed cell death - is still unknown. Here we replace each of these two residues by aspartate, in order to mimic phosphorylation, and report the structural and functional changes in the resulting cytochrome c variants. We find that the T28D mutant causes a 30-mV decrease on the midpoint redox potential and lowers the affinity for the distal site of Arabidopsis thaliana cytochrome c1 in complex III. Both the T28D and S47D variants display a higher efficiency as electron donors for the cytochrome c oxidase activity of complex IV. In both protein mutants, the peroxidase activity is significantly higher, which is related to the ability of cytochrome c to leave the mitochondria and reach the cytoplasm. We also find that both mutations at serine 47 (S47D and S47A) impair the ability of cytoplasmic cytochrome c to activate the caspases cascade, which is essential for triggering programmed cell death.
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105
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Mitochondrial emitted electromagnetic signals mediate retrograde signaling. Med Hypotheses 2015; 85:810-8. [DOI: 10.1016/j.mehy.2015.10.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Revised: 09/25/2015] [Accepted: 10/09/2015] [Indexed: 12/19/2022]
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Sommer S, Leistner M, Aleksic I, Schimmer C, Alhussini K, Kanofsky P, Leyh RG, Sommer SP. Impact of levosimendan and ischaemia-reperfusion injury on myocardial subsarcolemmal mitochondrial respiratory chain, mitochondrial membrane potential, Ca2+ cycling and ATP synthesis. Eur J Cardiothorac Surg 2015; 49:e54-62; discussion e62. [PMID: 26586791 DOI: 10.1093/ejcts/ezv397] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 10/01/2015] [Indexed: 02/04/2023] Open
Abstract
OBJECTIVES Levosimendan (LS) is increasingly used in case of myocardial failure after cardiac surgery. The impact of LS on myocardial mitochondrial functions, such as respiratory chain function (RCF), mitochondrial membrane potential (ΔΨm), Ca(2+) handling, mitochondrial permeability transition pore (mPTP) opening and ATP during ongoing ischaemia/reperfusion (IR) injury, is not well understood. Depending on LS, I/R injury or the combination of both, we analysed myocardial functions in a retrograde Langendorff-model followed by the analysis of subsarcolemmal mitochondrial (SSM) functions. METHODS Rat hearts were divided into four study groups; two were subjected to 30 min of perfusion without (control) or with the application of 1.4 µmol/20 min LS (Levo). Experiments were repeated with hearts being subjected to 40 min of normothermic stop-flow ischaemia and 30 min of reperfusion without (IR) or with LS application (Levo-IR). Systolic left ventricular pressure (LVPsys), left ventricular contractility (LVdp/dtmax) and coronary flow were determined. SSM were analysed regarding RCF, ΔΨm, ATP, and Ca(2+) retention capacity (CRC), Ca(2+)-induced swelling and Ca(2+) fluxes after (re)perfusion. RESULTS I/R injury suppressed LVdp/dtmax (1381 ± 927 vs 2464 ± 913 mmHg/s; P = 0.01 at 30 min (re-)perfusion time). IR revealed complex I-V state3 (19.1 ± 7.4 vs 27.6 ± 11.0 nmolO2/min; P < 0.044) and II-V state3 (20.6 ± 6.8 vs 37.3 ± 9.10 molO2/min; P < 0.0001) suppression and Levo limited I-V (14.8 ± 11.1 vs 27.6 ± 11.0 nmolO2/min; P < 0.001) and II-V (24.1 ± 6.4 vs 37.3 ± 9.10 molO2/min; P < 0.0001) function. After energizing, ΔΨm hypopolarization was observed in Levo (0.76 ± 0.04 vs 0.84 ± 0.04; P = 0.02), IR (0.75 ± 0.06 vs 0.84 ± 0.04; P = 0.007) and Levo-IR (0.75 ± 0.06 vs 0.06 ± 0.04; P = 0.01). IR (AUC: 626 vs 292; P = 0.023) and Levo-IR (AUC: 683 vs 292, P = 0.003) increased Ca(2+)-induced mPTP-opening susceptibility. CRC declined in IR (6.4 ± 2.1 vs 10.5 ± 2.6; P = 0.04) or Levo (6.5 ± 2.0 vs 10.5 ± 2.6; P = 0.023). Ca(2+) uptake was delayed in IR and Levo-IR without LS impact (P < 0.0001). Ca(2+) liberation was increased in Levo-IR. ATP synthesis was reduced in Levo (0.49 ± 0.14 vs 0.74 ± 0.14; P = 0.002) and Levo-I/R (0.34 ± 0.18 vs 0.74 ± 0.14; P < 0.002). CONCLUSION LS limited RCF at complex IV and V with ΔΨm hypopolarization suggesting a specific [Formula: see text]-dependent pathway. Ca(2+) redistribution from SSM by LS during I/R injury possibly prevents from Ca(2+) overload due to mPTP flickering. LS-induced mPTP flickering did not promote permanent Ca(2+)-induced mPTP opening. LS-dependent inhibition of ATP generation presumably resulted from complex IV and V limitations and lowered ΔΨm. However, a resulting impact of limited ATP synthesis on myocardial recovery remains arguable.
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Affiliation(s)
- Stefanie Sommer
- Department of Thoracic and Cardiovascular Surgery, University Hospital Würzburg, Würzburg, Germany
| | - Marcus Leistner
- Department of Thoracic and Cardiovascular Surgery, University Hospital Würzburg, Würzburg, Germany
| | - Ivan Aleksic
- Department of Thoracic and Cardiovascular Surgery, University Hospital Würzburg, Würzburg, Germany
| | - Christoph Schimmer
- Department of Thoracic and Cardiovascular Surgery, University Hospital Würzburg, Würzburg, Germany
| | - Khaled Alhussini
- Department of Thoracic and Cardiovascular Surgery, University Hospital Würzburg, Würzburg, Germany
| | - Peer Kanofsky
- Department of Thoracic and Cardiovascular Surgery, University Hospital Würzburg, Würzburg, Germany
| | - Rainer G Leyh
- Department of Thoracic and Cardiovascular Surgery, University Hospital Würzburg, Würzburg, Germany
| | - Sebastian-Patrick Sommer
- Department of Thoracic and Cardiovascular Surgery, University Hospital Würzburg, Würzburg, Germany Klinik f. Herz- und Gefäßchirurgie, Segeberger Kliniken, Bad Segeberg, Germany
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107
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Hiller S, DeKroon R, Hamlett ED, Xu L, Osorio C, Robinette J, Winnik W, Simington S, Maeda N, Alzate O, Yi X. Alpha-lipoic acid supplementation protects enzymes from damage by nitrosative and oxidative stress. Biochim Biophys Acta Gen Subj 2015; 1860:36-45. [PMID: 26344063 DOI: 10.1016/j.bbagen.2015.09.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 08/29/2015] [Accepted: 09/02/2015] [Indexed: 01/07/2023]
Abstract
BACKGROUND S-nitrosylation of mitochondrial enzymes involved in energy transfer under nitrosative stress may result in ATP deficiency. We investigated whether α-lipoic acid, a powerful antioxidant, could alleviate nitrosative stress by regulating S-nitrosylation, which could result in retaining the mitochondrial enzyme activity. METHODS In this study, we have identified the S-nitrosylated forms of subunit 1 of dihydrolipoyllysine succinyltransferase (complex III), and subunit 2 of the α-ketoglutarate dehydrogenase complex by implementing a fluorescence-based differential quantitative proteomics method. RESULTS We found that the activities of these two mitochondrial enzymes were partially but reversibly inhibited by S-nitrosylation in cultured endothelial cells, and that their activities were partially restored by supplementation of α-lipoic acid. We show that protein S-nitrosylation affects the activity of mitochondrial enzymes that are central to energy supply, and that α-lipoic acid protects mitochondrial enzymes by altering S-nitrosylation levels. CONCLUSIONS Inhibiting protein S-nitrosylation with α-lipoic acid seems to be a protective mechanism against nitrosative stress. GENERAL SIGNIFICANCE Identification and characterization of these new protein targets should contribute to expanding the therapeutic power of α-lipoic acid and to a better understanding of the underlying antioxidant mechanisms.
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Affiliation(s)
- Sylvia Hiller
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Robert DeKroon
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Eric D Hamlett
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC, United States
| | - Longquan Xu
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Cristina Osorio
- Systems Proteomics Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Jennifer Robinette
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC, United States; Systems Proteomics Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Witold Winnik
- Proteomic Research Core Unit, NHEERL, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States
| | - Stephen Simington
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Nobuyo Maeda
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Oscar Alzate
- Texas A&M Health Science Center, College Station, TX, United States.
| | - Xianwen Yi
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States.
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108
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Guerra-Castellano A, Díaz-Quintana A, Moreno-Beltrán B, López-Prados J, Nieto PM, Meister W, Staffa J, Teixeira M, Hildebrandt P, De la Rosa MA, Díaz-Moreno I. Mimicking Tyrosine Phosphorylation in Human Cytochrome c by the Evolved tRNA Synthetase Technique. Chemistry 2015; 21:15004-12. [PMID: 26329855 DOI: 10.1002/chem.201502019] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Indexed: 11/08/2022]
Abstract
Phosphorylation of tyrosine 48 of cytochrome c is related to a wide range of human diseases due to the pleiotropic role of the heme-protein in cell life and death. However, the structural conformation and physicochemical properties of phosphorylated cytochrome c are difficult to study as its yield from cell extracts is very low and its kinase remains unknown. Herein, we report a high-yielding synthesis of a close mimic of phosphorylated cytochrome c, developed by optimization of the synthesis of the non-canonical amino acid p-carboxymethyl-L-phenylalanine (pCMF) and its efficient site-specific incorporation at position 48. It is noteworthy that the Y48pCMF mutation significantly destabilizes the Fe-Met bond in the ferric form of cytochrome c, thereby lowering the pKa value for the alkaline transition of the heme-protein. This finding reveals the differential ability of the phosphomimic protein to drive certain events. This modified cytochrome c might be an important tool to investigate the role of the natural protein following phosphorylation.
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Affiliation(s)
| | - Antonio Díaz-Quintana
- IBVF - cicCartuja, Universidad de Sevilla - CSIC, Avenida Américo Vespucio 49, Sevilla 41092 (Spain).
| | - Blas Moreno-Beltrán
- IBVF - cicCartuja, Universidad de Sevilla - CSIC, Avenida Américo Vespucio 49, Sevilla 41092 (Spain)
| | - Javier López-Prados
- IIQ - cicCartuja, Universidad de Sevilla - CSIC, Avenida Américo Vespucio 49, Sevilla 41092 (Spain)
| | - Pedro M Nieto
- IIQ - cicCartuja, Universidad de Sevilla - CSIC, Avenida Américo Vespucio 49, Sevilla 41092 (Spain)
| | - Wiebke Meister
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin (Germany)
| | - Jana Staffa
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin (Germany)
| | - Miguel Teixeira
- Instituto de Tecnologia Química e Biológica, António Xavier Universidade Nova de Lisboa, Avenida da República, 2780-157 Oeiras (Portugal)
| | - Peter Hildebrandt
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin (Germany)
| | - Miguel A De la Rosa
- IBVF - cicCartuja, Universidad de Sevilla - CSIC, Avenida Américo Vespucio 49, Sevilla 41092 (Spain)
| | - Irene Díaz-Moreno
- IBVF - cicCartuja, Universidad de Sevilla - CSIC, Avenida Américo Vespucio 49, Sevilla 41092 (Spain).
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Edmunds LR, Sharma L, Wang H, Kang A, d’Souza S, Lu J, McLaughlin M, Dolezal JM, Gao X, Weintraub ST, Ding Y, Zeng X, Yates N, Prochownik EV. c-Myc and AMPK Control Cellular Energy Levels by Cooperatively Regulating Mitochondrial Structure and Function. PLoS One 2015; 10:e0134049. [PMID: 26230505 PMCID: PMC4521957 DOI: 10.1371/journal.pone.0134049] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 07/04/2015] [Indexed: 12/25/2022] Open
Abstract
The c-Myc (Myc) oncoprotein and AMP-activated protein kinase (AMPK) regulate glycolysis and oxidative phosphorylation (Oxphos) although often for different purposes. Because Myc over-expression depletes ATP with the resultant activation of AMPK, we explored the potential co-dependency of and cross-talk between these proteins by comparing the consequences of acute Myc induction in ampk+/+ (WT) and ampk-/- (KO) murine embryo fibroblasts (MEFs). KO MEFs showed a higher basal rate of glycolysis than WT MEFs and an appropriate increase in response to activation of a Myc-estrogen receptor (MycER) fusion protein. However, KO MEFs had a diminished ability to increase Oxphos, mitochondrial mass and reactive oxygen species in response to MycER activation. Other differences between WT and KO MEFs, either in the basal state or following MycER induction, included abnormalities in electron transport chain function, levels of TCA cycle-related oxidoreductases and cytoplasmic and mitochondrial redox states. Transcriptional profiling of pathways pertinent to glycolysis, Oxphos and mitochondrial structure and function also uncovered significant differences between WT and KO MEFs and their response to MycER activation. Finally, an unbiased mass-spectrometry (MS)-based survey capable of quantifying ~40% of all mitochondrial proteins, showed about 15% of them to be AMPK- and/or Myc-dependent in their steady state. Significant differences in the activities of the rate-limiting enzymes pyruvate kinase and pyruvate dehydrogenase, which dictate pyruvate and acetyl coenzyme A abundance, were also differentially responsive to Myc and AMPK and could account for some of the differences in basal metabolite levels that were also detected by MS. Thus, Myc and AMPK are highly co-dependent and appear to engage in significant cross-talk across numerous pathways which support metabolic and ATP-generating functions.
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Affiliation(s)
- Lia R. Edmunds
- Section of Hematology/Oncology, Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States of America
- The University of Pittsburgh School of Medicine, Pittsburgh, PA, United States of America
| | - Lokendra Sharma
- Section of Hematology/Oncology, Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States of America
| | - Huabo Wang
- Section of Hematology/Oncology, Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States of America
| | - Audry Kang
- The University of Pittsburgh School of Medicine, Pittsburgh, PA, United States of America
| | - Sonia d’Souza
- Section of Hematology/Oncology, Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States of America
| | - Jie Lu
- Section of Hematology/Oncology, Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States of America
| | - Michael McLaughlin
- The University of Pittsburgh School of Medicine, Pittsburgh, PA, United States of America
| | - James M. Dolezal
- The University of Pittsburgh School of Medicine, Pittsburgh, PA, United States of America
| | - Xiaoli Gao
- Department of Biochemistry, The University of Texas Health Science Center at San Antonio, San Antonio TX, United States of America
| | - Susan T. Weintraub
- Department of Biochemistry, The University of Texas Health Science Center at San Antonio, San Antonio TX, United States of America
| | - Ying Ding
- Department of Biostatistics, The University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Xuemei Zeng
- Department of Cell Biology, The University of Pittsburgh School of Medicine, Pittsburgh, PA, United States of America
| | - Nathan Yates
- Department of Cell Biology, The University of Pittsburgh School of Medicine, Pittsburgh, PA, United States of America
| | - Edward V. Prochownik
- Section of Hematology/Oncology, Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States of America
- The University of Pittsburgh School of Medicine, Pittsburgh, PA, United States of America
- Department of Microbiology and Molecular Genetics, The University of Pittsburgh School of Medicine, Pittsburgh, PA, United States of America
- The Hillman Cancer Center, The University of Pittsburgh, Pittsburgh, PA, United States of America
- * E-mail:
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Kadenbach B, Hüttemann M. The subunit composition and function of mammalian cytochrome c oxidase. Mitochondrion 2015; 24:64-76. [PMID: 26190566 DOI: 10.1016/j.mito.2015.07.002] [Citation(s) in RCA: 156] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Revised: 07/03/2015] [Accepted: 07/08/2015] [Indexed: 12/31/2022]
Abstract
Cytochrome c oxidase (COX) from mammals and birds is composed of 13 subunits. The three catalytic subunits I-III are encoded by mitochondrial DNA, the ten nuclear-coded subunits (IV, Va, Vb, VIa, VIb, VIc, VIIa, VIIb, VIIc, VIII) by nuclear DNA. The nuclear-coded subunits are essentially involved in the regulation of oxygen consumption and proton translocation by COX, since their removal or modification changes the activity and their mutation causes mitochondrial diseases. Respiration, the basis for ATP synthesis in mitochondria, is differently regulated in organs and species by expression of tissue-, developmental-, and species-specific isoforms for COX subunits IV, VIa, VIb, VIIa, VIIb, and VIII, but the holoenzyme in mammals is always composed of 13 subunits. Various proteins and enzymes were shown, e.g., by co-immunoprecipitation, to bind to specific COX subunits and modify its activity, but these interactions are reversible, in contrast to the tightly bound 13 subunits. In addition, the formation of supercomplexes with other oxidative phosphorylation complexes has been shown to be largely variable. The regulatory complexity of COX is increased by protein phosphorylation. Up to now 18 phosphorylation sites have been identified under in vivo conditions in mammals. However, only for a few phosphorylation sites and four nuclear-coded subunits could a specific function be identified. Research on the signaling pathways leading to specific COX phosphorylations remains a great challenge for understanding the regulation of respiration and ATP synthesis in mammalian organisms. This article reviews the function of the individual COX subunits and their isoforms, as well as proteins and small molecules interacting and regulating the enzyme.
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Affiliation(s)
| | - Maik Hüttemann
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA
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111
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Molecular Mechanisms and Therapeutic Effects of (-)-Epicatechin and Other Polyphenols in Cancer, Inflammation, Diabetes, and Neurodegeneration. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2015:181260. [PMID: 26180580 PMCID: PMC4477097 DOI: 10.1155/2015/181260] [Citation(s) in RCA: 160] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 12/23/2014] [Accepted: 12/31/2014] [Indexed: 01/13/2023]
Abstract
With recent insight into the mechanisms involved in diseases, such as cardiovascular disease, cancer, stroke, neurodegenerative diseases, and diabetes, more efficient modes of treatment are now being assessed. Traditional medicine including the use of natural products is widely practiced around the world, assuming that certain natural products contain the healing properties that may in fact have a preventative role in many of the diseases plaguing the human population. This paper reviews the biological effects of a group of natural compounds called polyphenols, including apigenin, epigallocatechin gallate, genistein, and (-)-epicatechin, with a focus on the latter. (-)-Epicatechin has several unique features responsible for a variety of its effects. One of these is its ability to interact with and neutralize reactive oxygen species (ROS) in the cell. (-)-Epicatechin also modulates cell signaling including the MAP kinase pathway, which is involved in cell proliferation. Mutations in this pathway are often associated with malignancies, and the use of (-)-epicatechin holds promise as a preventative agent and as an adjunct for chemotherapy and radiation therapy to improve outcome. This paper discusses the potential of some phenolic compounds to maintain, protect, and possibly reinstate health.
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YANG YUANZHENG, FAN TINGTING, GAO FENG, FU JUAN, LIU QIONG. Exogenous cytochrome c inhibits the expression of transforming growth factor-β1 in a mouse model of sepsis-induced myocardial dysfunction via the SMAD1/5/8 signaling pathway. Mol Med Rep 2015; 12:2189-96. [DOI: 10.3892/mmr.2015.3629] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Accepted: 11/25/2014] [Indexed: 11/06/2022] Open
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Nowak G, Bakajsova D. Protein kinase C-α interaction with F0F1-ATPase promotes F0F1-ATPase activity and reduces energy deficits in injured renal cells. J Biol Chem 2015; 290:7054-66. [PMID: 25627689 DOI: 10.1074/jbc.m114.588244] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
We showed previously that active PKC-α maintains F0F1-ATPase activity, whereas inactive PKC-α mutant (dnPKC-α) blocks recovery of F0F1-ATPase activity after injury in renal proximal tubules (RPTC). This study tested whether mitochondrial PKC-α interacts with and phosphorylates F0F1-ATPase. Wild-type PKC-α (wtPKC-α) and dnPKC-α were overexpressed in RPTC to increase their mitochondrial levels, and RPTC were exposed to oxidant or hypoxia. Mitochondrial levels of the γ-subunit, but not the α- and β-subunits, were decreased by injury, an event associated with 54% inhibition of F0F1-ATPase activity. Overexpressing wtPKC-α blocked decreases in γ-subunit levels, maintained F0F1-ATPase activity, and improved ATP levels after injury. Deletion of PKC-α decreased levels of α-, β-, and γ-subunits, decreased F0F1-ATPase activity, and hindered the recovery of ATP content after RPTC injury. Mitochondrial PKC-α co-immunoprecipitated with α-, β-, and γ-subunits of F0F1-ATPase. The association of PKC-α with these subunits decreased in injured RPTC overexpressing dnPKC-α. Immunocapture of F0F1-ATPase and immunoblotting with phospho(Ser) PKC substrate antibody identified phosphorylation of serine in the PKC consensus site on the α- or β- and γ-subunits. Overexpressing wtPKC-α increased phosphorylation and protein levels, whereas deletion of PKC-α decreased protein levels of α-, β-, and γ-subunits of F0F1-ATPase in RPTC. Phosphoproteomics revealed phosphorylation of Ser(146) on the γ subunit in response to wtPKC-α overexpression. We concluded that active PKC-α 1) prevents injury-induced decreases in levels of γ subunit of F0F1-ATPase, 2) interacts with α-, β-, and γ-subunits leading to increases in their phosphorylation, and 3) promotes the recovery of F0F1-ATPase activity and ATP content after injury in RPTC.
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Affiliation(s)
- Grażyna Nowak
- From the Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Diana Bakajsova
- From the Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
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Measurement of technetium-99m sestamibi signals in rats administered a mitochondrial uncoupler and in a rat model of heart failure. PLoS One 2015; 10:e0117091. [PMID: 25594546 PMCID: PMC4297193 DOI: 10.1371/journal.pone.0117091] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 12/18/2014] [Indexed: 01/06/2023] Open
Abstract
Background Many methods have been used to assess mitochondrial function. Technetium-99m sestamibi (99mTc-MIBI), a lipophilic cation, is rapidly incorporated into myocardial cells by diffusion and mainly localizes to the mitochondria. The purpose of this study was to investigate whether measurement of 99mTc-MIBI signals in animal models could be used as a tool to quantify mitochondrial membrane potential at the organ level. Methods and Results We analyzed 99mTc-MIBI signals in Sprague-Dawley (SD) rat hearts perfused with carbonyl cyanide m-chlorophenylhydrazone (CCCP), a mitochondrial uncoupler known to reduce the mitochondrial membrane potential. 99mTc-MIBI signals could be used to detect changes in the mitochondrial membrane potential with sensitivity comparable to that obtained by two-photon laser microscopy with the cationic probe tetramethylrhodamine ethyl ester (TMRE). We also measured 99mTc-MIBI signals in the hearts of SD rats administered CCCP (4 mg/kg intraperitoneally) or vehicle. 99mTc-MIBI signals decreased in rat hearts administered CCCP, and the ATP content, as measured by 31P magnetic resonance spectroscopy, decreased simultaneously. Next, we administered 99mTc-MIBI to Dahl salt-sensitive rats fed a high-salt diet, which leads to hypertension and heart failure. The 99mTc-MIBI signal per heart tissue weight was inversely correlated with heart weight, cardiac function, and the expression of atrial natriuretic factor, a marker of heart failure, and positively correlated with the accumulation of labeled fatty acid analog. The 99mTc-MIBI signal per liver tissue weight was lower than that per heart tissue weight. Conclusion Measurement of 99mTc-MIBI signals can be an effective tool for semiquantitative investigation of cardiac mitochondrial membrane potential in the SD rat model by using a chemical to decrease the mitochondrial membrane potential. The 99mTc-MIBI signal per heart tissue weight was inversely correlated with the severity of heart failure in the Dahl rat model.
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Welch AJ, Bedoya-Reina OC, Carretero-Paulet L, Miller W, Rode KD, Lindqvist C. Polar bears exhibit genome-wide signatures of bioenergetic adaptation to life in the arctic environment. Genome Biol Evol 2015; 6:433-50. [PMID: 24504087 PMCID: PMC3942037 DOI: 10.1093/gbe/evu025] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Polar bears (Ursus maritimus) face extremely cold temperatures and periods of fasting, which might result in more severe energetic challenges than those experienced by their sister species, the brown bear (U. arctos). We have examined the mitochondrial and nuclear genomes of polar and brown bears to investigate whether polar bears demonstrate lineage-specific signals of molecular adaptation in genes associated with cellular respiration/energy production. We observed increased evolutionary rates in the mitochondrial cytochrome c oxidase I gene in polar but not brown bears. An amino acid substitution occurred near the interaction site with a nuclear-encoded subunit of the cytochrome c oxidase complex and was predicted to lead to a functional change, although the significance of this remains unclear. The nuclear genomes of brown and polar bears demonstrate different adaptations related to cellular respiration. Analyses of the genomes of brown bears exhibited substitutions that may alter the function of proteins that regulate glucose uptake, which could be beneficial when feeding on carbohydrate-dominated diets during hyperphagia, followed by fasting during hibernation. In polar bears, genes demonstrating signatures of functional divergence and those potentially under positive selection were enriched in functions related to production of nitric oxide (NO), which can regulate energy production in several different ways. This suggests that polar bears may be able to fine-tune intracellular levels of NO as an adaptive response to control trade-offs between energy production in the form of adenosine triphosphate versus generation of heat (thermogenesis).
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Affiliation(s)
- Andreanna J Welch
- Department of Biological Sciences, University at Buffalo (SUNY), Buffalo
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MNRR1 (formerly CHCHD2) is a bi-organellar regulator of mitochondrial metabolism. Mitochondrion 2015; 20:43-51. [DOI: 10.1016/j.mito.2014.10.003] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 09/12/2014] [Accepted: 10/08/2014] [Indexed: 12/20/2022]
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Adenovirus 36 attenuates weight loss from exercise but improves glycemic control by increasing mitochondrial activity in the liver. PLoS One 2014; 9:e114534. [PMID: 25479564 PMCID: PMC4257667 DOI: 10.1371/journal.pone.0114534] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 11/10/2014] [Indexed: 12/17/2022] Open
Abstract
Human adenovirus type 36 (Ad36) as an obesity agent induces adiposity by increasing glucose uptake and promoting chronic inflammation in fat tissues; in contrast, exercise reduces total body fat and inflammation. Our objective was to determine the association between Ad36 and the effects of exercise on inflammation and glycemic control. In the human trials (n = 54), Korean children (aged 12–14 years) exercised for 60 min on three occasions each week for 2 months. We compared the body mass index (BMI) Z-scores before and after exercise. C57BL/6 mice were infected with Ad36 and Ad2 as a control, and these mice exercised for 12 weeks postinfection. After the exercise period, we determined the serum parameters and assessed the presence of inflammation and the mitochondrial function in the organs. Ad36-seropositive children who were subjected to a supervised exercise regimen had high BMI Z-scores whereas Ad36-seronegative children had lower scores. Similarly, Ad36-infected mice were resistant to weight loss and exhibited chronic inflammation of their adipose tissues despite frequent exercise. However, Ad36 combined with exercise reduced the levels of serum glucose, nonesterified fatty acids, total cholesterol, and insulin in virus-infected mice. Interestingly, virus infection increased the mitochondrial function in the liver, as demonstrated by the numbers of mitochondria, cytochrome c oxidase activity, and transcription of key mitochondrial genes. Therefore Ad36 counteracts the weight-loss effect of exercise and maintains the chronic inflammatory state, but glycemic control is improved by exercise synergistically because of increased mitochondrial activity in the liver.
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Wang XY, Ma ZC, Wang YG, Tan HL, Xiao CR, Liang QD, Tang XL, Cheng Y, Gao Y. Tetramethylpyrazine protects lymphocytes from radiation-induced apoptosis through nuclear factor-κB. Chin J Nat Med 2014; 12:730-7. [PMID: 25443365 DOI: 10.1016/s1875-5364(14)60112-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Indexed: 11/18/2022]
Abstract
AIM Radiation induces an important apoptosis response in irradiated organs. The objective of this study was to investigate the radioprotective effect of tetramethylpyrazine (TMP) on irradiated lymphocytes and discover the possible mechanism of protection. METHOD Lymphocytes were pretreated for 12 h with TMP (25-200 μmol·L(-1)) and then exposed to 4 Gy radiation. Cell apoptosis and the signaling pathway were analyzed. RESULTS Irradiation increased cell death, DNA fragmentation, activated caspase activation and cytochrome c translocation, downregulated B-cell lymphoma 2 (Bcl-2) and up-regulated Bcl-2-associated X protein (Bax). Pretreated with TMP significantly reversed this tendency. Several anti-apoptotic characteristics of TMP, including the ability to increase cell viability, inhibit caspase-9 activation, and upregulate Bcl-2 and down-regulate Bax in 4Gy-irradiated lymphocytes were determined. Signal pathway analysis showed TMP could translate nuclear factor-κB (NF-κB) from cytosol into the nucleus. CONCLUSION The results suggest that TMP had a radioprotective effect through the NF-κB pathway to inhibit apoptosis, and it may be an effective candidate for treating radiation diseases associated with cell apoptosis.
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Affiliation(s)
- Xiao-Yan Wang
- Institute of Radiation Medicine, Academy of Military Medical Science, Beijing 100850, China; Chongqing Maternal and Child Health-Care Hospital, Chongqing 400016, China
| | - Zeng-Chun Ma
- Institute of Radiation Medicine, Academy of Military Medical Science, Beijing 100850, China.
| | - Yu-Guang Wang
- Institute of Radiation Medicine, Academy of Military Medical Science, Beijing 100850, China
| | - Hong-Ling Tan
- Institute of Radiation Medicine, Academy of Military Medical Science, Beijing 100850, China
| | - Cheng-Rong Xiao
- Institute of Radiation Medicine, Academy of Military Medical Science, Beijing 100850, China
| | - Qian-De Liang
- Institute of Radiation Medicine, Academy of Military Medical Science, Beijing 100850, China
| | - Xiang-Lin Tang
- Institute of Radiation Medicine, Academy of Military Medical Science, Beijing 100850, China
| | - Yu Cheng
- Chongqing Maternal and Child Health-Care Hospital, Chongqing 400016, China
| | - Yue Gao
- Institute of Radiation Medicine, Academy of Military Medical Science, Beijing 100850, China.
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Shen Y, Yang J, Li J, Shi X, Ouyang L, Tian Y, Lu J. Carnosine inhibits the proliferation of human gastric cancer SGC-7901 cells through both of the mitochondrial respiration and glycolysis pathways. PLoS One 2014; 9:e104632. [PMID: 25115854 PMCID: PMC4130552 DOI: 10.1371/journal.pone.0104632] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 07/15/2014] [Indexed: 12/19/2022] Open
Abstract
Carnosine, a naturally occurring dipeptide, has been recently demonstrated to possess anti-tumor activity. However, its underlying mechanism is unclear. In this study, we investigated the effect and mechanism of carnosine on the cell viability and proliferation of the cultured human gastric cancer SGC-7901 cells. Carnosine treatment did not induce cell apoptosis or necrosis, but reduced the proliferative capacity of SGC-7901 cells. Seahorse analysis showed SGC-7901 cells cultured with pyruvate have active mitochondria, and depend on mitochondrial oxidative phosphorylation more than glycolysis pathway for generation of ATP. Carnosine markedly decreased the absolute value of mitochondrial ATP-linked respiration, and reduced the maximal oxygen consumption and spare respiratory capacity, which may reduce mitochondrial function correlated with proliferative potential. Simultaneously, carnosine also reduced the extracellular acidification rate and glycolysis of SGC-7901 cells. Our results suggested that carnosine is a potential regulator of energy metabolism of SGC-7901 cells both in the anaerobic and aerobic pathways, and provided a clue for preclinical and clinical evaluation of carnosine for gastric cancer therapy.
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Affiliation(s)
- Yao Shen
- Key Laboratory of Laboratory Medicine, Ministry of Education, Attardi Institute of Mitochondrial Biomedicine and Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou, China
- * E-mail: (YS); (JXL)
| | - Jianbo Yang
- Key Laboratory of Laboratory Medicine, Ministry of Education, Attardi Institute of Mitochondrial Biomedicine and Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou, China
| | - Juan Li
- Key Laboratory of Laboratory Medicine, Ministry of Education, Attardi Institute of Mitochondrial Biomedicine and Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou, China
| | - Xiaojie Shi
- Key Laboratory of Laboratory Medicine, Ministry of Education, Attardi Institute of Mitochondrial Biomedicine and Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou, China
| | - Li Ouyang
- Key Laboratory of Laboratory Medicine, Ministry of Education, Attardi Institute of Mitochondrial Biomedicine and Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou, China
| | - Yueyang Tian
- Key Laboratory of Laboratory Medicine, Ministry of Education, Attardi Institute of Mitochondrial Biomedicine and Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou, China
| | - Jianxin Lu
- Key Laboratory of Laboratory Medicine, Ministry of Education, Attardi Institute of Mitochondrial Biomedicine and Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou, China
- * E-mail: (YS); (JXL)
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Bremer K, Kocha K, Snider T, Moyes C. Energy metabolism and cytochrome oxidase activity: linking metabolism to gene expression. CAN J ZOOL 2014. [DOI: 10.1139/cjz-2013-0267] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Modification of mitochondrial content demands the synthesis of hundreds of proteins encoded by nuclear and mitochondrial genomes. The responsibility for coordination of this process falls to nuclear-encoded master regulators of transcription. DNA-binding proteins and coactivators integrate information from energy-sensing pathways and hormones to alter mitochondrial gene expression. In mammals, the signaling cascade for mitochondrial biogenesis can be described as follows: hormonal signals and energetic information are sensed by protein-modifying enzymes that in turn regulate the post-translational modification of transcription factors. Once activated, transcription-factor complexes form on promoter elements of many of the nuclear-encoded mitochondrial genes, recruiting proteins that remodel chromatin and initiate transcription. One master regulator in mammals, PGC-1α, is well studied because of its role in determining the metabolic phenotype of muscles, but also due to its importance in mitochondria-related metabolic diseases. However, relatively little is known about the role of this pathway in other vertebrates. These uncertainties raise broader questions about the evolutionary origins of the pathway and its role in generating the diversity in muscle metabolic phenotypes seen in nature.
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Affiliation(s)
- K. Bremer
- Department of Biology, Biosciences Complex, Queen’s University, Kingston, ON K7L 3N6, Canada
| | - K.M. Kocha
- Department of Biology, Biosciences Complex, Queen’s University, Kingston, ON K7L 3N6, Canada
| | - T. Snider
- Department of Biology, Biosciences Complex, Queen’s University, Kingston, ON K7L 3N6, Canada
| | - C.D. Moyes
- Department of Biology, Biosciences Complex, Queen’s University, Kingston, ON K7L 3N6, Canada
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Short-term exposure of nontumorigenic human bronchial epithelial cells to carcinogenic chromium(VI) compromises their respiratory capacity and alters their bioenergetic signature. FEBS Open Bio 2014; 4:594-601. [PMID: 25161867 PMCID: PMC4141194 DOI: 10.1016/j.fob.2014.06.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 06/18/2014] [Accepted: 06/23/2014] [Indexed: 12/24/2022] Open
Abstract
Chromium(VI) impaired respiration and increased glycolytic flux in BEAS-2B cells. Cr(VI)-exposed cells shifted to a more fermentative metabolism. This metabolic shift was in line with a decreased β-F1-ATPase/GAPDH protein ratio. Increased oxidative stress levels suggest impairment of antioxidant defenses.
Previous studies on the impact of hexavalent chromium [Cr(VI)] on mammalian cell energetics revealed alterations suggestive of a shift to a more fermentative metabolism. Aiming at a more defined understanding of the metabolic effects of Cr(VI) and of their molecular basis, we assessed the impact of a mild Cr(VI) exposure on critical bioenergetic parameters (lactate production, oxygen consumption and intracellular ATP levels). Cells derived from normal human bronchial epithelium (BEAS-2B cell line), the main in vivo target of Cr(VI) carcinogenicity, were subjected for 48 h to 1 μM Cr(VI). We could confirm a shift to a more fermentative metabolism, resulting from the simultaneous inhibition of respiration and stimulation of glycolysis. This shift was accompanied by a decrease in the protein levels of the catalytic subunit (subunit β) of the mitochondrial H+-ATP synthase (β-F1-ATPase) and a concomitant marked increase in those of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The corresponding alteration in the β-F1-ATPase/GAPDH protein ratio (viewed as a bioenergetic signature) upon Cr(VI) exposure was in agreement with the observed attenuation of cellular respiration and enhancement of glycolytic flux. Altogether, these results constitute a novel finding in terms of the molecular mechanisms of Cr(VI) effects.
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Key Words
- 2,4-DNP, 2,4-dinitrophenol
- 2-DG, 2-deoxyglucose
- Aerobic glycolysis
- Cellular bioenergetic index
- Cellular energy status
- Cellular respiration
- Chromate lung cancer
- Cr(III), trivalent chromium
- Cr(IV), tetravalent chromium
- Cr(V), pentavalent chromium
- Cr(VI), hexavalent chromium
- DCF, 2′,7′-dichlorofluorescein
- EDTA, ethylenediaminetetracetic acid
- ETC, mitochondrial electron transport chain
- GAPDH, glyceraldehyde-3-phosphate dehydrogenase
- IARC, International Agency for Research on Cancer
- OCR, oxygen consumption rate
- OXPHOS, oxidative phosphorylation
- PBS, phosphate-buffered saline
- PI, propidium iodide
- ROS, reactive oxygen species
- TCA, tricarboxylic acid
- Warburg effect
- β-F1-ATPase, catalytic subunit (subunit β) of the mitochondrial H+-ATP synthase
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Bociąga-Jasik M, Polus A, Góralska J, Czech U, Gruca A, Śliwa A, Garlicki A, Mach T, Dembińska-Kieć A. Metabolic effects of the HIV protease inhibitor--saquinavir in differentiating human preadipocytes. Pharmacol Rep 2014; 65:937-50. [PMID: 24145088 DOI: 10.1016/s1734-1140(13)71075-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2012] [Revised: 03/12/2013] [Indexed: 11/30/2022]
Abstract
BACKGROUND The iatrogenic, HIV-related lipodystrophy is associated with development of the significant metabolic and cardiovascular complications. The underlying mechanisms of antiretroviral (ARV) drugs are not completely explored. METHODS The aim of the study was to characterize effects of the protease inhibitor (PI)--saquinavir (SQV) on metabolic functions, and gene expression during differentiation in cells (Chub-S7) culture. RESULTS SQV in concentrations observed during antiretroviral therapy (ART) significantly decreased mitochondrial membrane potential (MMP), oxygen consumption and ATP generation. The effects were greater in already differentiated cells. This was accompanied by characteristic changes in the expression of the genes involved in endoplasmic reticulum (ER) stress, and differentiation (lipid droplet formation) process such as: WNT10a, C/EBPa, AFT4, CIDEC, ADIPOQ, LPIN1. CONCLUSIONS The results indicate that SQV affects not only metabolic (mitochondrial) activity of adipocytes, but affects the expression of genes related to differentiation and to a lesser extent to cell apoptosis.
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Affiliation(s)
- Monika Bociąga-Jasik
- Chair of Gastroenterology, Hepatology and Infectious Diseases, Department of Infectious Diseases, Jagiellonian University, Collegium Medicum, Sniadeckich 5, PL 31-501 Kraków, Poland.
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Hiller S, DeKroon R, Xu L, Robinette J, Winnik W, Alzate O, Simington S, Maeda N, Yi X. α-Lipoic acid protects mitochondrial enzymes and attenuates lipopolysaccharide-induced hypothermia in mice. Free Radic Biol Med 2014; 71:362-367. [PMID: 24675228 PMCID: PMC5293729 DOI: 10.1016/j.freeradbiomed.2014.03.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2013] [Revised: 03/14/2014] [Accepted: 03/15/2014] [Indexed: 01/13/2023]
Abstract
Hypothermia is a key symptom of sepsis, but the mechanism(s) leading to hypothermia during sepsis is largely unknown and thus no effective therapy is available for hypothermia. Therefore, it is important to investigate the mechanism and develop effective therapeutic methods. Lipopolysaccharide (LPS)-induced hypothermia accompanied by excess nitric oxide (NO) production leads to a reduction in energy production in wild-type mice. However, mice lacking inducible nitric oxide synthase did not suffer from LPS-induced hypothermia, suggesting that hypothermia is associated with excess NO production during sepsis. This observation is supported by the treatment of wild-type mice with α-lipoic acid (LA) in that it effectively attenuates LPS-induced hypothermia with decreased NO production. We also found that LA partially restored ATP production, and activities of the mitochondrial enzymes involved in energy metabolism, which were inhibited during sepsis. These data suggest that hypothermia is related to mitochondrial dysfunction, which is probably compromised by excess NO production and that LA administration attenuates hypothermia mainly by protecting mitochondrial enzymes from NO damage.
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Affiliation(s)
- Sylvia Hiller
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7525, USA
| | - Robert DeKroon
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7525, USA
| | - Longquan Xu
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7525, USA
| | - Jennifer Robinette
- Program of Molecular Biology and Biotechnology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7525, USA
| | - Witold Winnik
- Proteomic Research Core Unit, NHEERL, U.S. Environmental Protection Agency, Research Triangle Park, Durham, NC 27711, USA
| | - Oscar Alzate
- Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, TX 79905, USA
| | - Stephen Simington
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7525, USA
| | - Nobuyo Maeda
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7525, USA
| | - Xianwen Yi
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7525, USA.
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Wolken GG, Arriaga EA. Simultaneous measurement of individual mitochondrial membrane potential and electrophoretic mobility by capillary electrophoresis. Anal Chem 2014; 86:4217-26. [PMID: 24673334 PMCID: PMC4018156 DOI: 10.1021/ac403849x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
![]()
Mitochondrial membrane
potential varies, depending on energy demand,
subcellular location, and morphology and is commonly used as an indicator
of mitochondrial functional status. Electrophoretic mobility is a
heterogeneous surface property reflective of mitochondrial surface
composition and morphology, which could be used as a basis for separation
of mitochondrial subpopulations. Since these properties are heterogeneous,
methods for their characterization in individual mitochondria are
needed to better design and understand electrophoretic separations
of subpopulations of mitochondria. Here we report on the first method
for simultaneous determination of individual mitochondrial membrane
potential and electrophoretic mobility by capillary electrophoresis
with laser-induced fluorescence detection (CE-LIF). Mitochondria were
isolated from cultured cells, mouse muscle, or liver, and then polarized,
labeled with JC-1 (a ratiometric fluorescent probe, which indicates
changes in membrane potential), and separated with CE-LIF. Red/green
fluorescence intensity ratios from individual mitochondria were used
as an indicator of mitochondrial membrane potential. Reproducible
distributions of individual mitochondrial membrane potential and electrophoretic
mobility were observed. Analysis of polarized and depolarized regions
of interest defined using red/green ratios and runs of depolarized
controls allowed for the determination of membrane potential and comparison
of electrophoretic mobility distributions in preparations containing
depolarized mitochondria. Through comparison of these regions of interest,
we observed dependence of electrophoretic mobility on membrane potential,
with polarized regions of interest displaying decreased electrophoretic
mobility. This method could be applied to investigate mitochondrial
heterogeneity in aging or disease models where membrane potential
is an important factor.
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Affiliation(s)
- Gregory G Wolken
- Department of Chemistry, University of Minnesota , 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
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Vygodina TV, Kirichenko A, Konstantinov AA. Cation binding site of cytochrome c oxidase: progress report. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:1188-95. [PMID: 24607866 DOI: 10.1016/j.bbabio.2014.02.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 02/18/2014] [Accepted: 02/24/2014] [Indexed: 12/15/2022]
Abstract
Cytochrome c oxidase from bovine heart binds Ca(2+) reversibly at a specific Cation Binding Site located near the outer face of the mitochondrial membrane. Ca(2+) shifts the absorption spectrum of heme a, which allowed earlier the determination of the kinetic and equilibrium characteristics of the binding, and, as shown recently, the binding of calcium to the site inhibits cytochrome oxidase activity at low turnover rates of the enzyme [Vygodina, Т., Kirichenko, A., Konstantinov, A.A (2013). Direct Regulation of Cytochrome c Oxidase by Calcium Ions. PloS ONE 8, e74436]. This paper summarizes further progress in the studies of the Cation Binding Site in this group presenting the results to be reported at 18th EBEC Meeting in Lisbon, 2014. The paper revises specificity of the bovine oxidase Cation Binding Site for different cations, describes dependence of the Ca(2+)-induced inhibition on turnover rate of the enzyme and reports very high affinity binding of calcium with the "slow" form of cytochrome oxidase. This article is part of a Special Issue entitled: 18th European Bioenergetic Conference. Guest Editors: Manuela Pereira and Miguel Teixeira.
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Affiliation(s)
- Tatiana V Vygodina
- A.N. Belozersky Research Institute of Physico-Chemical Biology, Moscow State University, Russia
| | - Anna Kirichenko
- A.N. Belozersky Research Institute of Physico-Chemical Biology, Moscow State University, Russia
| | - Alexander A Konstantinov
- A.N. Belozersky Research Institute of Physico-Chemical Biology, Moscow State University, Russia.
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126
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Dingley SD, Polyak E, Ostrovsky J, Srinivasan S, Lee I, Rosenfeld AB, Tsukikawa M, Xiao R, Selak MA, Coon JJ, Hebert AS, Grimsrud PA, Kwon YJ, Pagliarini DJ, Gai X, Schurr TG, Hüttemann M, Nakamaru-Ogiso E, Falk MJ. Mitochondrial DNA variant in COX1 subunit significantly alters energy metabolism of geographically divergent wild isolates in Caenorhabditis elegans. J Mol Biol 2014; 426:2199-216. [PMID: 24534730 DOI: 10.1016/j.jmb.2014.02.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 02/05/2014] [Accepted: 02/06/2014] [Indexed: 12/12/2022]
Abstract
Mitochondrial DNA (mtDNA) sequence variation can influence the penetrance of complex diseases and climatic adaptation. While studies in geographically defined human populations suggest that mtDNA mutations become fixed when they have conferred metabolic capabilities optimally suited for a specific environment, it has been challenging to definitively assign adaptive functions to specific mtDNA sequence variants in mammals. We investigated whether mtDNA genome variation functionally influences Caenorhabditis elegans wild isolates of distinct mtDNA lineages and geographic origins. We found that, relative to N2 (England) wild-type nematodes, CB4856 wild isolates from a warmer native climate (Hawaii) had a unique p.A12S amino acid substitution in the mtDNA-encoded COX1 core catalytic subunit of mitochondrial complex IV (CIV). Relative to N2, CB4856 worms grown at 20°C had significantly increased CIV enzyme activity, mitochondrial matrix oxidant burden, and sensitivity to oxidative stress but had significantly reduced lifespan and mitochondrial membrane potential. Interestingly, mitochondrial membrane potential was significantly increased in CB4856 grown at its native temperature of 25°C. A transmitochondrial cybrid worm strain, chpIR (M, CB4856>N2), was bred as homoplasmic for the CB4856 mtDNA genome in the N2 nuclear background. The cybrid strain also displayed significantly increased CIV activity, demonstrating that this difference results from the mtDNA-encoded p.A12S variant. However, chpIR (M, CB4856>N2) worms had significantly reduced median and maximal lifespan relative to CB4856, which may relate to their nuclear-mtDNA genome mismatch. Overall, these data suggest that C. elegans wild isolates of varying geographic origins may adapt to environmental challenges through mtDNA variation to modulate critical aspects of mitochondrial energy metabolism.
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Affiliation(s)
- Stephen D Dingley
- Division of Human Genetics, Department of Pediatrics, The Children's Hospital of Philadelphia and University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Erzsebet Polyak
- Division of Human Genetics, Department of Pediatrics, The Children's Hospital of Philadelphia and University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Julian Ostrovsky
- Division of Human Genetics, Department of Pediatrics, The Children's Hospital of Philadelphia and University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Satish Srinivasan
- Department of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Icksoo Lee
- Dankook University College of Medicine, Yongin-si, Gyeonggi-do, South Korea
| | - Amy B Rosenfeld
- Department of Molecular Pharmacology and Therapeutics, Loyola University Health Sciences Division, Maywood, IL, 60153, USA
| | - Mai Tsukikawa
- Division of Human Genetics, Department of Pediatrics, The Children's Hospital of Philadelphia and University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Rui Xiao
- Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Mary A Selak
- Mitochondria Research Core Facility, The Children's Hospital of Philadelphia Research Institute, Philadelphia, PA, 19104, USA
| | - Joshua J Coon
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA; Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA; Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Alexander S Hebert
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA; Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Paul A Grimsrud
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Young Joon Kwon
- Division of Human Genetics, Department of Pediatrics, The Children's Hospital of Philadelphia and University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA.
| | - David J Pagliarini
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Xiaowu Gai
- Department of Molecular Pharmacology and Therapeutics, Loyola University Health Sciences Division, Maywood, IL, 60153, USA
| | - Theodore G Schurr
- Department of Anthropology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Maik Hüttemann
- Center for Molecular Medicine and Genetics and Cardiovascular Research Institute, Wayne State University School of Medicine, Detroit, MI, 48201, USA
| | - Eiko Nakamaru-Ogiso
- Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104, USA
| | - Marni J Falk
- Division of Human Genetics, Department of Pediatrics, The Children's Hospital of Philadelphia and University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA.
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127
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Elbaz HA, Lee I, Antwih DA, Liu J, Hüttemann M, Zielske SP. Epicatechin stimulates mitochondrial activity and selectively sensitizes cancer cells to radiation. PLoS One 2014; 9:e88322. [PMID: 24516636 PMCID: PMC3916420 DOI: 10.1371/journal.pone.0088322] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 01/13/2014] [Indexed: 12/27/2022] Open
Abstract
Radiotherapy is the treatment of choice for solid tumors including pancreatic cancer, but the effectiveness of treatment is limited by radiation resistance. Resistance to chemotherapy or radiotherapy is associated with reduced mitochondrial respiration and drugs that stimulate mitochondrial respiration may decrease radiation resistance. The objectives of this study were to evaluate the potential of (-)-epicatechin to stimulate mitochondrial respiration in cancer cells and to selectively sensitize cancer cells to radiation. We investigated the natural compound (-)-epicatechin for effects on mitochondrial respiration and radiation resistance of pancreatic and glioblastoma cancer cells using a Clark type oxygen electrode, clonogenic survival assays, and Western blot analyses. (-)-Epicatechin stimulated mitochondrial respiration and oxygen consumption in Panc-1 cells. Human normal fibroblasts were not affected. (-)-Epicatechin sensitized Panc-1, U87, and MIA PaCa-2 cells with an average radiation enhancement factor (REF) of 1.7, 1.5, and 1.2, respectively. (-)-Epicatechin did not sensitize normal fibroblast cells to ionizing radiation with a REF of 0.9, suggesting cancer cell selectivity. (-)-Epicatechin enhanced Chk2 phosphorylation and p21 induction when combined with radiation in cancer, but not normal, cells. Taken together, (-)-epicatechin radiosensitized cancer cells, but not normal cells, and may be a promising candidate for pancreatic cancer treatment when combined with radiation.
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Affiliation(s)
- Hosam A. Elbaz
- Department of Radiation Oncology, Wayne State University, Detroit, Michigan, United States of America
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, United States of America
- Wayne State University and Karmanos Cancer Institute, Detroit, Michigan, United States of America
| | - Icksoo Lee
- College of Medicine, Dankook University, Cheonan-si, Chungcheongnam-do, Republic of Korea
| | - Deborah A. Antwih
- Department of Radiation Oncology, Wayne State University, Detroit, Michigan, United States of America
- Wayne State University and Karmanos Cancer Institute, Detroit, Michigan, United States of America
| | - Jenney Liu
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, United States of America
- Wayne State University and Karmanos Cancer Institute, Detroit, Michigan, United States of America
| | - Maik Hüttemann
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, United States of America
- Cardiovascular Research Institute, Wayne State University, Detroit, Michigan, United States of America
- Wayne State University and Karmanos Cancer Institute, Detroit, Michigan, United States of America
| | - Steven P. Zielske
- Department of Radiation Oncology, Wayne State University, Detroit, Michigan, United States of America
- Wayne State University and Karmanos Cancer Institute, Detroit, Michigan, United States of America
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128
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Nykky J, Vuento M, Gilbert L. Role of mitochondria in parvovirus pathology. PLoS One 2014; 9:e86124. [PMID: 24465910 PMCID: PMC3897641 DOI: 10.1371/journal.pone.0086124] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 12/09/2013] [Indexed: 01/06/2023] Open
Abstract
Proper functioning of the mitochondria is crucial for the survival of the cell. Viruses are able to interfere with mitochondrial functions as they infect the host cell. Parvoviruses are known to induce apoptosis in infected cells, but the role of the mitochondria in parvovirus induced cytopathy is only partially known. Here we demonstrate with confocal and electron microscopy that canine parvovirus (CPV) associated with the mitochondrial outer membrane from the onset of infection. During viral entry a transient depolarization of the mitochondrial transmembrane potential and increase in ROS level was detected. Subsequently, mitochondrial homeostasis was normalized shortly, as detected by repolarization of the mitochondrial membrane and decrease of ROS. Indeed, activation of cell survival signalling through ERK1/2 cascade was observed early in CPV infected cells. At 12 hours post infection, concurrent with the expression of viral non-structural protein 1, damage to the mitochondrial structure and depolarization of its membrane were apparent. Results of this study provide additional insight of parvovirus pathology and also more general information of virus-mitochondria association.
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Affiliation(s)
- Jonna Nykky
- Department of Biological and Environmental Science, and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Matti Vuento
- Department of Biological and Environmental Science, and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Leona Gilbert
- Department of Biological and Environmental Science, and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
- * E-mail:
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129
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Affiliation(s)
- J. William O. Ballard
- School of Biotechnology and Biomolecular Sciences; University of New South Wales; Sydney New South Wales 2052 Australia
| | - Nicolas Pichaud
- School of Biotechnology and Biomolecular Sciences; University of New South Wales; Sydney New South Wales 2052 Australia
- Laboratoire de Biologie Intégrative; Département de Biologie, Chimie et Géographie; Université du Québec à Rimouski; Rimouski Quebec Canada
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130
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Clanton TL, Hogan MC, Gladden LB. Regulation of cellular gas exchange, oxygen sensing, and metabolic control. Compr Physiol 2013; 3:1135-90. [PMID: 23897683 DOI: 10.1002/cphy.c120030] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cells must continuously monitor and couple their metabolic requirements for ATP utilization with their ability to take up O2 for mitochondrial respiration. When O2 uptake and delivery move out of homeostasis, cells have elaborate and diverse sensing and response systems to compensate. In this review, we explore the biophysics of O2 and gas diffusion in the cell, how intracellular O2 is regulated, how intracellular O2 levels are sensed and how sensing systems impact mitochondrial respiration and shifts in metabolic pathways. Particular attention is paid to how O2 affects the redox state of the cell, as well as the NO, H2S, and CO concentrations. We also explore how these agents can affect various aspects of gas exchange and activate acute signaling pathways that promote survival. Two kinds of challenges to gas exchange are also discussed in detail: when insufficient O2 is available for respiration (hypoxia) and when metabolic requirements test the limits of gas exchange (exercising skeletal muscle). This review also focuses on responses to acute hypoxia in the context of the original "unifying theory of hypoxia tolerance" as expressed by Hochachka and colleagues. It includes discourse on the regulation of mitochondrial electron transport, metabolic suppression, shifts in metabolic pathways, and recruitment of cell survival pathways preventing collapse of membrane potential and nuclear apoptosis. Regarding exercise, the issues discussed relate to the O2 sensitivity of metabolic rate, O2 kinetics in exercise, and influences of available O2 on glycolysis and lactate production.
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Affiliation(s)
- T L Clanton
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, USA.
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131
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Anand SK, Tikoo SK. Viruses as modulators of mitochondrial functions. Adv Virol 2013; 2013:738794. [PMID: 24260034 PMCID: PMC3821892 DOI: 10.1155/2013/738794] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 08/30/2013] [Indexed: 02/07/2023] Open
Abstract
Mitochondria are multifunctional organelles with diverse roles including energy production and distribution, apoptosis, eliciting host immune response, and causing diseases and aging. Mitochondria-mediated immune responses might be an evolutionary adaptation by which mitochondria might have prevented the entry of invading microorganisms thus establishing them as an integral part of the cell. This makes them a target for all the invading pathogens including viruses. Viruses either induce or inhibit various mitochondrial processes in a highly specific manner so that they can replicate and produce progeny. Some viruses encode the Bcl2 homologues to counter the proapoptotic functions of the cellular and mitochondrial proteins. Others modulate the permeability transition pore and either prevent or induce the release of the apoptotic proteins from the mitochondria. Viruses like Herpes simplex virus 1 deplete the host mitochondrial DNA and some, like human immunodeficiency virus, hijack the host mitochondrial proteins to function fully inside the host cell. All these processes involve the participation of cellular proteins, mitochondrial proteins, and virus specific proteins. This review will summarize the strategies employed by viruses to utilize cellular mitochondria for successful multiplication and production of progeny virus.
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Affiliation(s)
- Sanjeev K. Anand
- Vaccine & Infection Disease Organization-International Vaccine Center (VIDO-InterVac), University of Saskatchewan, 120 Veterinary Road, Saskatoon, SK, Canada S7E 5E3
- Veterinary Microbiology, University of Saskatchewan, 120 Veterinary Road, Saskatoon, SK, Canada S7E 5E3
| | - Suresh K. Tikoo
- Vaccine & Infection Disease Organization-International Vaccine Center (VIDO-InterVac), University of Saskatchewan, 120 Veterinary Road, Saskatoon, SK, Canada S7E 5E3
- Veterinary Microbiology, University of Saskatchewan, 120 Veterinary Road, Saskatoon, SK, Canada S7E 5E3
- School of Public Health, University of Saskatchewan, 120 Veterinary Road, Saskatoon, SK, Canada S7E 5E3
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132
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Aichler M, Elsner M, Ludyga N, Feuchtinger A, Zangen V, Maier SK, Balluff B, Schöne C, Hierber L, Braselmann H, Meding S, Rauser S, Zischka H, Aubele M, Schmitt M, Feith M, Hauck SM, Ueffing M, Langer R, Kuster B, Zitzelsberger H, Höfler H, Walch AK. Clinical response to chemotherapy in oesophageal adenocarcinoma patients is linked to defects in mitochondria. J Pathol 2013; 230:410-9. [PMID: 23592244 DOI: 10.1002/path.4199] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 02/25/2013] [Accepted: 03/28/2013] [Indexed: 12/13/2022]
Abstract
Chemotherapeutic drugs kill cancer cells, but it is unclear why this happens in responding patients but not in non-responders. Proteomic profiles of patients with oesophageal adenocarcinoma may be helpful in predicting response and selecting more effective treatment strategies. In this study, pretherapeutic oesophageal adenocarcinoma biopsies were analysed for proteomic changes associated with response to chemotherapy by MALDI imaging mass spectrometry. Resulting candidate proteins were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and investigated for functional relevance in vitro. Clinical impact was validated in pretherapeutic biopsies from an independent patient cohort. Studies on the incidence of these defects in other solid tumours were included. We discovered that clinical response to cisplatin correlated with pre-existing defects in the mitochondrial respiratory chain complexes of cancer cells, caused by loss of specific cytochrome c oxidase (COX) subunits. Knockdown of a COX protein altered chemosensitivity in vitro, increasing the propensity of cancer cells to undergo cell death following cisplatin treatment. In an independent validation, patients with reduced COX protein expression prior to treatment exhibited favourable clinical outcomes to chemotherapy, whereas tumours with unchanged COX expression were chemoresistant. In conclusion, previously undiscovered pre-existing defects in mitochondrial respiratory complexes cause cancer cells to become chemosensitive: mitochondrial defects lower the cells' threshold for undergoing cell death in response to cisplatin. By contrast, cancer cells with intact mitochondrial respiratory complexes are chemoresistant and have a high threshold for cisplatin-induced cell death. This connection between mitochondrial respiration and chemosensitivity is relevant to anticancer therapeutics that target the mitochondrial electron transport chain.
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Affiliation(s)
- Michaela Aichler
- Research Unit of Analytical Pathology, Institute of Pathology, Helmholtz Zentrum München-German Research Centre for Environmental Health, Neuherberg, Germany
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133
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Vygodina T, Kirichenko A, Konstantinov AA. Direct regulation of cytochrome c oxidase by calcium ions. PLoS One 2013; 8:e74436. [PMID: 24058566 PMCID: PMC3769247 DOI: 10.1371/journal.pone.0074436] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 08/01/2013] [Indexed: 12/16/2022] Open
Abstract
Cytochrome c oxidase from bovine heart binds Ca2+ reversibly at a specific Cation Binding Site located near the outer face of the mitochondrial membrane. Ca2+ shifts the absorption spectrum of heme a, which allowed previously to determine the kinetics and equilibrium characteristics of the binding. However, no effect of Ca2+ on the functional characteristics of cytochrome oxidase was revealed earlier. Here we report that Ca2+ inhibits cytochrome oxidase activity of isolated bovine heart enzyme by 50–60% with Ki of ∼1 µM, close to Kd of calcium binding with the oxidase determined spectrophotometrically. The inhibition is observed only at low, but physiologically relevant, turnover rates of the enzyme (∼10 s−1 or less). No inhibitory effect of Ca2+ is observed under conventional conditions of cytochrome c oxidase activity assays (turnover number >100 s−1 at pH 8), which may explain why the effect was not noticed earlier. The inhibition is specific for Ca2+ and is reversed by EGTA. Na+ ions that compete with Ca2+ for binding with the Cation Binding Site, do not affect significantly activity of the enzyme but counteract the inhibitory effect of Ca2+. The Ca2+-induced inhibition of cytochrome c oxidase is observed also with the uncoupled mitochondria from several rat tissues. At the same time, calcium ions do not inhibit activity of the homologous bacterial cytochrome oxidases. Possible mechanisms of the inhibition are discussed as well as potential physiological role of Ca2+ binding with cytochrome oxidase. Ca2+- binding at the Cation Binding Site is proposed to inhibit proton-transfer through the exit part of the proton conducting pathway H in the mammalian oxidases.
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Affiliation(s)
- Tatiana Vygodina
- A. N. Belozersky Institute of Physico-Chemical Biology, M. V. Lomonosov Moscow State University, Moscow, Russia
| | - Anna Kirichenko
- A. N. Belozersky Institute of Physico-Chemical Biology, M. V. Lomonosov Moscow State University, Moscow, Russia
| | - Alexander A. Konstantinov
- A. N. Belozersky Institute of Physico-Chemical Biology, M. V. Lomonosov Moscow State University, Moscow, Russia
- * E-mail:
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134
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Baile MG, Whited K, Claypool SM. Deacylation on the matrix side of the mitochondrial inner membrane regulates cardiolipin remodeling. Mol Biol Cell 2013; 24:2008-20. [PMID: 23637464 PMCID: PMC3681703 DOI: 10.1091/mbc.e13-03-0121] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Our understanding of the clinically relevant tafazzin-mediated cardiolipin (CL) remodeling pathway is incomplete. In this study, a new trafficking step required for CL remodeling has been identified. Further, it is demonstrated that flux through this CL remodeling pathway is controlled by the strength of the mitochondrial electrochemical gradient. The mitochondrial-specific lipid cardiolipin (CL) is required for numerous processes therein. After its synthesis on the matrix-facing leaflet of the inner membrane (IM), CL undergoes acyl chain remodeling to achieve its final form. In yeast, this process is completed by the transacylase tafazzin, which associates with intermembrane space (IMS)-facing membrane leaflets. Mutations in TAZ1 result in the X-linked cardiomyopathy Barth syndrome. Amazingly, despite this clear pathophysiological association, the physiological importance of CL remodeling is unresolved. In this paper, we show that the lipase initiating CL remodeling, Cld1p, is associated with the matrix-facing leaflet of the mitochondrial IM. Thus monolysocardiolipin generated by Cld1p must be transported to IMS-facing membrane leaflets to gain access to tafazzin, identifying a previously unknown step required for CL remodeling. Additionally, we show that Cld1p is the major site of regulation in CL remodeling; and that, like CL biosynthesis, CL remodeling is augmented in growth conditions requiring mitochondrially produced energy. However, unlike CL biosynthesis, dissipation of the mitochondrial membrane potential stimulates CL remodeling, identifying a novel feedback mechanism linking CL remodeling to oxidative phosphorylation capacity.
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Affiliation(s)
- Matthew G Baile
- Department of Physiology, Johns Hopkins School of Medicine, Baltimore, MD 21205-2185, USA
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135
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Mitochondrial mechanisms of neuroglobin's neuroprotection. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2013; 2013:756989. [PMID: 23634236 PMCID: PMC3619637 DOI: 10.1155/2013/756989] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 12/24/2012] [Accepted: 02/21/2013] [Indexed: 01/18/2023]
Abstract
Neuroglobin (Ngb) is an oxygen-binding globin protein that has been demonstrated to be neuroprotective against stroke and related neurological disorders. However, the underlying mechanisms of Ngb's neuroprotection remain largely undefined. Mitochondria play critical roles in multiple physiological pathways including cell respiration, energy production, free radical generation, and cellular homeostasis and apoptosis. Mitochondrial dysfunction is widely involved in the pathogenesis of stroke and neurodegenerative diseases including Alzheimer's, Parkinson's, and Huntington's diseases. Accumulating evidence showed that elevated Ngb level is associated with preserved mitochondrial function, suggesting that Ngb may play neuroprotective roles through mitochondria-mediated pathways. In this paper we briefly discuss the mitochondria-related mechanisms in Ngb's neuroprotection, especially those involved in ATP production, ROS generation and scavenging, and mitochondria-mediated cell death signaling pathways.
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136
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Dutta D, Xu J, Kim JS, Dunn WA, Leeuwenburgh C. Upregulated autophagy protects cardiomyocytes from oxidative stress-induced toxicity. Autophagy 2013; 9:328-44. [PMID: 23298947 DOI: 10.4161/auto.22971] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Autophagy is a cellular self-digestion process that mediates protein quality control and serves to protect against neurodegenerative disorders, infections, inflammatory diseases and cancer. Current evidence suggests that autophagy can selectively remove damaged organelles such as the mitochondria. Mitochondria-induced oxidative stress has been shown to play a major role in a wide range of pathologies in several organs, including the heart. Few studies have investigated whether enhanced autophagy can offer protection against mitochondrially-generated oxidative stress. We induced mitochondrial stress in cardiomyocytes using antimycin A (AMA), which increased mitochondrial superoxide generation, decreased mitochondrial membrane potential and depressed cellular respiration. In addition, AMA augmented nuclear DNA oxidation and cell death in cardiomyocytes. Interestingly, although oxidative stress has been proposed to induce autophagy, treatment with AMA did not result in stimulation of autophagy or mitophagy in cardiomyocytes. Our results showed that the MTOR inhibitor rapamycin induced autophagy, promoted mitochondrial clearance and protected cardiomyocytes from the cytotoxic effects of AMA, as assessed by apoptotic marker activation and viability assays in both mouse atrial HL-1 cardiomyocytes and human ventricular AC16 cells. Importantly, rapamycin improved mitochondrial function, as determined by cellular respiration, mitochondrial membrane potential and morphology analysis. Furthermore, autophagy induction by rapamycin suppressed the accumulation of ubiquitinylated proteins induced by AMA. Inhibition of rapamycin-induced autophagy by pharmacological or genetic interventions attenuated the cytoprotective effects of rapamycin against AMA. We propose that rapamycin offers cytoprotection against oxidative stress by a combined approach of removing dysfunctional mitochondria as well as by degrading damaged, ubiquitinated proteins. We conclude that autophagy induction by rapamycin could be utilized as a potential therapeutic strategy against oxidative stress-mediated damage in cardiomyocytes.
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Affiliation(s)
- Debapriya Dutta
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, USA
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137
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High efficiency versus maximal performance--the cause of oxidative stress in eukaryotes: a hypothesis. Mitochondrion 2012. [PMID: 23178790 DOI: 10.1016/j.mito.2012.11.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Degenerative diseases are in part based on elevated production of ROS (reactive oxygen species) in mitochondria, mainly during stress and excessive work under stress (strenuous exercise). The production of ROS increases with increasing mitochondrial membrane potential (ΔΨ(m)). A mechanism is described which is suggested to keep ΔΨ(m) at low values under normal conditions thus preventing ROS formation, but is switched off under stress and excessive work to maximize the rate of ATP synthesis, accompanied by decreased efficiency. Low ΔΨ(m) and low ROS production are suggested to occur by inhibition of respiration at high [ATP]/[ADP] ratios. The nucleotides interact with phosphorylated cytochrome c oxidase (COX), representing the step with the highest flux-control coefficient of mitochondrial respiration. At stress and excessive work neural signals are suggested to dephosphorylate the enzyme and abolish the control of COX activity (respiration) by the [ATP]/[ADP] ratio with consequent increase of ΔΨ(m) and ROS production. The control of COX by the [ATP]/[ADP] ratio, in addition, is proposed to increase the efficiency of ATP production via a third proton pumping pathway, identified in eukaryotic but not in prokaryotic COX. We conclude that 'oxidative stress' occurs when the control of COX activity by the [ATP]/[ADP] ratio is switched off via neural signals.
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138
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Edelfosine and perifosine disrupt hepatic mitochondrial oxidative phosphorylation and induce the permeability transition. Mitochondrion 2012; 13:25-35. [PMID: 23164800 DOI: 10.1016/j.mito.2012.11.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 11/02/2012] [Accepted: 11/07/2012] [Indexed: 12/25/2022]
Abstract
Edelfosine and perifosine are alkylphospholipids that have been intensively studied as potential antitumor agents. Apoptotic cell death caused by these two compounds is mediated, at least in part, through mitochondria. Additionally, previous works demonstrated that edelfosine induces changes in mitochondrial membrane permeability that are somehow reduced by using cyclosporin A. Therefore, the objective of the present study was not only to confirm mitochondrial permeability transition but also identify direct effects of both ether lipids on mitochondrial hepatic fractions, namely on mitochondrial oxidative phosphorylation and generation of hydrogen peroxide (H(2)O(2)) through the respiratory chain. Results show that edelfosine and perifosine inhibit mitochondrial respiration and decrease transmembrane electric potential. However, despite these effects, edelfosine and perifosine were still able to induce mitochondrial permeability transition in non-energized mitochondria. Interestingly, edelfosine decreased H(2)O(2) production through the respiratory chain. In conclusion, the present work demonstrates previously unknown alterations of mitochondrial physiology directly induced by edelfosine and perifosine. The study is relevant in the understanding of mitochondrial-target effects of both compounds, as well as to acknowledge possible toxic responses in non-tumor organs.
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139
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Helling S, Hüttemann M, Ramzan R, Kim SH, Lee I, Müller T, Langenfeld E, Meyer HE, Kadenbach B, Vogt S, Marcus K. Multiple phosphorylations of cytochrome c oxidase and their functions. Proteomics 2012; 12:950-9. [PMID: 22522801 DOI: 10.1002/pmic.201100618] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Cytochrome c oxidase (COX), the terminal enzyme of the mitochondrial electron transport chain, is regulated by isozyme expression, allosteric effectors such as the ATP/ADP ratio, and reversible phosphorylation. Of particular interest is the "allosteric ATP-inhibition," which has been hypothesized to keep the mitochondrial membrane potential at low healthy values (<140 mV), thus preventing the formation of superoxide radical anions, which have been implicated in multiple degenerative diseases. It has been proposed that the "allosteric ATP-inhibition" is switched on by the protein kinase A-dependent phosphorylation of COX. The goal of this study was to identify the phosphorylation site(s) involved in the "allosteric ATP-inhibition" of COX. We report the mass spectrometric identification of four new phosphorylation sites in bovine heart COX. The identified phosphorylation sites include Tyr-218 in subunit II, Ser-1 in subunit Va, Ser-2 in subunit Vb, and Ser-1 in subunit VIIc. With the exception of Ser-2 in subunit Vb, the identified phosphorylation sites were found in enzyme samples with and without "allosteric ATP inhibition," making Ser-2 of subunit Vb a candidate site enabling allosteric regulation. We therefore hypothesize that additional phosphorylation(s) may be required for the "allosteric ATP-inhibition," and that these sites may be easily dephosphorylated or difficult to identify by mass spectrometry.
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Affiliation(s)
- Stefan Helling
- Medizinisches Proteom-Center, Funktionelle Proteomik, Ruhr-Universität Bochum, Bochum, Germany
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140
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Sanderson TH, Reynolds CA, Kumar R, Przyklenk K, Hüttemann M. Molecular mechanisms of ischemia-reperfusion injury in brain: pivotal role of the mitochondrial membrane potential in reactive oxygen species generation. Mol Neurobiol 2012; 47:9-23. [PMID: 23011809 DOI: 10.1007/s12035-012-8344-z] [Citation(s) in RCA: 465] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 08/27/2012] [Indexed: 12/20/2022]
Abstract
Stroke and circulatory arrest cause interferences in blood flow to the brain that result in considerable tissue damage. The primary method to reduce or prevent neurologic damage to patients suffering from brain ischemia is prompt restoration of blood flow to the ischemic tissue. However, paradoxically, restoration of blood flow causes additional damage and exacerbates neurocognitive deficits among patients who suffer a brain ischemic event. Mitochondria play a critical role in reperfusion injury by producing excessive reactive oxygen species (ROS) thereby damaging cellular components, and initiating cell death. In this review, we summarize our current understanding of the mechanisms of mitochondrial ROS generation during reperfusion, and specifically, the role the mitochondrial membrane potential plays in the pathology of cerebral ischemia/reperfusion. Additionally, we propose a temporal model of ROS generation in which posttranslational modifications of key oxidative phosphorylation (OxPhos) proteins caused by ischemia induce a hyperactive state upon reintroduction of oxygen. Hyperactive OxPhos generates high mitochondrial membrane potentials, a condition known to generate excessive ROS. Such a state would lead to a "burst" of ROS upon reperfusion, thereby causing structural and functional damage to the mitochondria and inducing cell death signaling that eventually culminate in tissue damage. Finally, we propose that strategies aimed at modulating this maladaptive hyperpolarization of the mitochondrial membrane potential may be a novel therapeutic intervention and present specific studies demonstrating the cytoprotective effect of this treatment modality.
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Affiliation(s)
- Thomas H Sanderson
- Cardiovascular Research Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA.
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141
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Hüttemann M, Lee I, Grossman LI, Doan JW, Sanderson TH. Phosphorylation of mammalian cytochrome c and cytochrome c oxidase in the regulation of cell destiny: respiration, apoptosis, and human disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 748:237-64. [PMID: 22729861 DOI: 10.1007/978-1-4614-3573-0_10] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The mitochondrial oxidative phosphorylation (OxPhos) system not only generates the vast majority of cellular energy, but is also involved in the generation of reactive oxygen species (ROS), and apoptosis. Cytochrome c (Cytc) and cytochrome c oxidase (COX) represent the terminal step of the electron transport chain (ETC), the proposed rate-limiting reaction in mammals. Cytc and COX show unique regulatory features including allosteric regulation, isoform expression, and regulation through cell signaling pathways. This chapter focuses on the latter and discusses all mapped phosphorylation sites based on the crystal structures of COX and Cytc. Several signaling pathways have been identified that target COX including protein kinase A and C, receptor tyrosine kinase, and inflammatory signaling. In addition, four phosphorylation sites have been mapped on Cytc with potentially large implications due to its multiple functions including apoptosis, a pathway that is overactive in stressed cells but inactive in cancer. The role of COX and Cytc phosphorylation is reviewed in a human disease context, including cancer, inflammation, sepsis, asthma, and ischemia/reperfusion injury as seen in myocardial infarction and ischemic stroke.
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Affiliation(s)
- Maik Hüttemann
- Wayne State University School of Medicine, Detroit, MI, USA.
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142
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Caza TN, Talaber G, Perl A. Metabolic regulation of organelle homeostasis in lupus T cells. Clin Immunol 2012; 144:200-13. [PMID: 22836085 PMCID: PMC3423541 DOI: 10.1016/j.clim.2012.07.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 07/03/2012] [Indexed: 12/23/2022]
Abstract
Abnormal T-cell signaling and activation are characteristic features in systemic lupus erythematosus (SLE). Lupus T cells are shifted toward an over-activated state, important signaling pathways are rewired, and signaling molecules are replaced. Disturbances in metabolic and organelle homeostasis, importantly within the mitochondrial, endosomal, and autophagosomal compartments, underlie the changes in signal transduction. Mitochondrial hyperpolarization, enhanced endosomal recycling, and dysregulated autophagy are hallmarks of pathologic organelle homeostasis in SLE. This review is focused on the metabolic checkpoints of endosomal traffic that control immunological synapse formation and mitophagy and may thus serve as targets for treatment in SLE.
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Affiliation(s)
- Tiffany N Caza
- Department of Medicine, State University of New York Upstate Medical University, Syracuse, 13210, USA
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143
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Auger C, Appanna V, Castonguay Z, Han S, Appanna VD. A facile electrophoretic technique to monitor phosphoenolpyruvate-dependent kinases. Electrophoresis 2012; 33:1095-101. [PMID: 22539312 DOI: 10.1002/elps.201100517] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Phosphoenolpyruvate (PEP)-dependent kinases are central to numerous metabolic processes and mediate the production of adenosine triphosphate (ATP) by substrate-level phosphorylation (SLP). While pyruvate kinase (PK, EC: 2.7.1.40), the final enzyme of the glycolytic pathway is critical in the anaerobic synthesis of ATP from ADP, pyruvate phosphate dikinase (PPDK, EC: 2.7.9.1), and phosphoenolpyruvate synthase (PEPS, EC: 2.7.9.2) help generate ATP from AMP coupled to PEP as a substrate. Here we demonstrate an inexpensive and effective electrophoretic technology to determine the activities of these enzymes by blue-native polyacrylamide gel electrophoresis (BN-PAGE). The generation of pyruvate is linked to exogenous lactate dehydrogenase (LDH), and the oxidation of reduced nicotinamide adenine dinucleotide (NADH) coupled to 2,6-dichloroindophenol (DCIP) and iodonitrotetrazolium chloride (INT) results in a formazan precipitate which is easily quantifiable. The selectivity of the enzymes is ensured by including either AMP or ADP and pyrophosphate (PP(i) ) or inorganic phosphate (P(i) ). Activity bands were readily obtained after incubation in the respective reaction mixtures for 20-30 min. Cell-free extract concentrations as low as 20 μg protein equivalent yielded activity bands and substrate levels were manipulated to optimize sensitivity of this analytical technique. High-pressure liquid chromatography (HPLC), two-dimensional (2-D) SDS-PAGE (where SDS is sodium dodecyl sulfate), and immunoblot studies of the excised activity band help further characterize these PEP-dependent kinases. Furthermore, these enzymes were readily identified on the same gel by incubating it sequentially in the respective reaction mixtures. This technique provides a facile method to elucidate these kinases in biological systems.
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Affiliation(s)
- Christopher Auger
- Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, Canada
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144
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Barbi de Moura M, Vincent G, Fayewicz SL, Bateman NW, Hood BL, Sun M, Suhan J, Duensing S, Yin Y, Sander C, Kirkwood JM, Becker D, Conrads TP, Van Houten B, Moschos SJ. Mitochondrial respiration--an important therapeutic target in melanoma. PLoS One 2012; 7:e40690. [PMID: 22912665 PMCID: PMC3422349 DOI: 10.1371/journal.pone.0040690] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 06/11/2012] [Indexed: 12/20/2022] Open
Abstract
The importance of mitochondria as oxygen sensors as well as producers of ATP and reactive oxygen species (ROS) has recently become a focal point of cancer research. However, in the case of melanoma, little information is available to what extent cellular bioenergetics processes contribute to the progression of the disease and related to it, whether oxidative phosphorylation (OXPHOS) has a prominent role in advanced melanoma. In this study we demonstrate that compared to melanocytes, metastatic melanoma cells have elevated levels of OXPHOS. Furthermore, treating metastatic melanoma cells with the drug, Elesclomol, which induces cancer cell apoptosis through oxidative stress, we document by way of stable isotope labeling with amino acids in cell culture (SILAC) that proteins participating in OXPHOS are downregulated. We also provide evidence that melanoma cells with high levels of glycolysis are more resistant to Elesclomol. We further show that Elesclomol upregulates hypoxia inducible factor 1-α (HIF-1α), and that prolonged exposure of melanoma cells to this drug leads to selection of melanoma cells with high levels of glycolysis. Taken together, our findings suggest that molecular targeting of OXPHOS may have efficacy for advanced melanoma.
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Affiliation(s)
- Michelle Barbi de Moura
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Garret Vincent
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Shelley L. Fayewicz
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Nicholas W. Bateman
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Brian L. Hood
- Gynecologic Cancer Center of Excellence, Women's Health Integrated Research Center at Inova Health System, Annandale, Virginia, United States of America
| | - Mai Sun
- Department of Biostatistics, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Joseph Suhan
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Stefan Duensing
- Sektion Molekulare Uroonkologie, Urologische Universitätsklinik Heidelberg, Heidelberg, Germany
| | - Yan Yin
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Cindy Sander
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - John M. Kirkwood
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Dorothea Becker
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Thomas P. Conrads
- Gynecologic Cancer Center of Excellence, Women's Health Integrated Research Center at Inova Health System, Annandale, Virginia, United States of America
| | - Bennett Van Houten
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Stergios J. Moschos
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
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146
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Hüttemann M, Lee I, Gao X, Pecina P, Pecinova A, Liu J, Aras S, Sommer N, Sanderson TH, Tost M, Neff F, Aguilar-Pimentel JA, Becker L, Naton B, Rathkolb B, Rozman J, Favor J, Hans W, Prehn C, Puk O, Schrewe A, Sun M, Höfler H, Adamski J, Bekeredjian R, Graw J, Adler T, Busch DH, Klingenspor M, Klopstock T, Ollert M, Wolf E, Fuchs H, Gailus-Durner V, Hrabě de Angelis M, Weissmann N, Doan JW, Bassett DJP, Grossman LI. Cytochrome c oxidase subunit 4 isoform 2-knockout mice show reduced enzyme activity, airway hyporeactivity, and lung pathology. FASEB J 2012; 26:3916-30. [PMID: 22730437 DOI: 10.1096/fj.11-203273] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Cytochrome c oxidase (COX) is the terminal enzyme of the mitochondrial electron transport chain. The purpose of this study was to analyze the function of lung-specific cytochrome c oxidase subunit 4 isoform 2 (COX4i2) in vitro and in COX4i2-knockout mice in vivo. COX was isolated from cow lung and liver as control and functionally analyzed. COX4i2-knockout mice were generated and the effect of the gene knockout was determined, including COX activity, tissue energy levels, noninvasive and invasive lung function, and lung pathology. These studies were complemented by a comprehensive functional screen performed at the German Mouse Clinic (Neuherberg, Germany). We show that isolated cow lung COX containing COX4i2 is about twice as active (88 and 102% increased activity in the presence of allosteric activator ADP and inhibitor ATP, respectively) as liver COX, which lacks COX4i2. In COX4i2-knockout mice, lung COX activity and cellular ATP levels were significantly reduced (-50 and -29%, respectively). Knockout mice showed decreased airway responsiveness (60% reduced P(enh) and 58% reduced airway resistance upon challenge with 25 and 100 mg methacholine, respectively), and they developed a lung pathology deteriorating with age that included the appearance of Charcot-Leyden crystals. In addition, there was an interesting sex-specific phenotype, in which the knockout females showed reduced lean mass (-12%), reduced total oxygen consumption rate (-8%), improved glucose tolerance, and reduced grip force (-14%) compared to wild-type females. Our data suggest that high activity lung COX is a central determinant of airway function and is required for maximal airway responsiveness and healthy lung function. Since airway constriction requires energy, we propose a model in which reduced tissue ATP levels explain protection from airway hyperresponsiveness, i.e., absence of COX4i2 leads to reduced lung COX activity and ATP levels, which results in impaired airway constriction and thus reduced airway responsiveness; long-term lung pathology develops in the knockout mice due to impairment of energy-costly lung maintenance processes; and therefore, we propose mitochondrial oxidative phosphorylation as a novel target for the treatment of respiratory diseases, such as asthma.
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Affiliation(s)
- Maik Hüttemann
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA.
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147
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Gandra PG, Nogueira L, Hogan MC. Mitochondrial activation at the onset of contractions in isolated myofibres during successive contractile periods. J Physiol 2012; 590:3597-609. [PMID: 22711953 DOI: 10.1113/jphysiol.2012.232405] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
At the onset of skeletal muscle repetitive contractions, there is a significant delay in the time to achieve oxidative phosphorylation steady state. The purpose of the present study was to examine the factors that limit oxidative phosphorylation at the onset of contractions. NAD(P)H was measured in real time during two contractile periods (2 min each) separated by 5 min of rest in intact single muscle fibres (n = 7) isolated from Xenopus laevis. The fibres were then loaded with the dye tetramethylrhodamine methyl ester perchlorate (TMRM) to evaluate the kinetics of the mitochondrial membrane potential (Δψ (m)) during two further successive contractile periods. At the onset of contractions in the first period, NAD(P)H exhibited a time delay (14.1 ± 1.3 s) before decreasing toward a steady state. In contrast, Δψ(m) decreased immediately after the first contraction and started to be reestablished after 10.7 ± 0.9 s, with restoration to the pre-stimulation values after approximately 32 s. In the second contractile period (5 min after the first), NAD(P)H decreased immediately (i.e. no time delay) after the first contraction and had a significantly shorter time constant compared to the first contractile bout (3.3 ± 0.3 vs. 5.0 ± 0.2 s, P < 0.05). During the second bout, Δψ(m) remained unchanged from pre-stimulation values. These results suggest: (1) that at the onset of contractions, oxidative phosphorylation is primarily limited by the activity of the electron transport chain complexes rather than by a limited level of substrates; and (2) when the muscle is 'primed' by previous contractile activity, the faster enhancement of the cellular respiratory rate is due to intrinsic factors within the myofibre.
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Affiliation(s)
- Paulo G Gandra
- Department of Medicine-0623, University of California, San Diego, 9500 Gilman Drive La Jolla, CA 92093-0623, USA
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148
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Hüttemann M, Helling S, Sanderson TH, Sinkler C, Samavati L, Mahapatra G, Varughese A, Lu G, Liu J, Ramzan R, Vogt S, Grossman LI, Doan JW, Marcus K, Lee I. Regulation of mitochondrial respiration and apoptosis through cell signaling: cytochrome c oxidase and cytochrome c in ischemia/reperfusion injury and inflammation. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1817:598-609. [PMID: 21771582 PMCID: PMC3229836 DOI: 10.1016/j.bbabio.2011.07.001] [Citation(s) in RCA: 194] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 06/30/2011] [Accepted: 07/01/2011] [Indexed: 01/09/2023]
Abstract
Cytochrome c (Cytc) and cytochrome c oxidase (COX) catalyze the terminal reaction of the mitochondrial electron transport chain (ETC), the reduction of oxygen to water. This irreversible step is highly regulated, as indicated by the presence of tissue-specific and developmentally expressed isoforms, allosteric regulation, and reversible phosphorylations, which are found in both Cytc and COX. The crucial role of the ETC in health and disease is obvious since it, together with ATP synthase, provides the vast majority of cellular energy, which drives all cellular processes. However, under conditions of stress, the ETC generates reactive oxygen species (ROS), which cause cell damage and trigger death processes. We here discuss current knowledge of the regulation of Cytc and COX with a focus on cell signaling pathways, including cAMP/protein kinase A and tyrosine kinase signaling. Based on the crystal structures we highlight all identified phosphorylation sites on Cytc and COX, and we present a new phosphorylation site, Ser126 on COX subunit II. We conclude with a model that links cell signaling with the phosphorylation state of Cytc and COX. This in turn regulates their enzymatic activities, the mitochondrial membrane potential, and the production of ATP and ROS. Our model is discussed through two distinct human pathologies, acute inflammation as seen in sepsis, where phosphorylation leads to strong COX inhibition followed by energy depletion, and ischemia/reperfusion injury, where hyperactive ETC complexes generate pathologically high mitochondrial membrane potentials, leading to excessive ROS production. Although operating at opposite poles of the ETC activity spectrum, both conditions can lead to cell death through energy deprivation or ROS-triggered apoptosis.
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Affiliation(s)
- Maik Hüttemann
- Wayne State University School of Medicine, Detroit, MI 48201, USA.
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149
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Wangpaichitr M, Theodoropoulos G, Wu C, You M, Feun LG, Kuo MT, Savaraj N. The relationship of thioredoxin-1 and cisplatin resistance: its impact on ROS and oxidative metabolism in lung cancer cells. Mol Cancer Ther 2012; 11:604-15. [PMID: 22248473 PMCID: PMC3326609 DOI: 10.1158/1535-7163.mct-11-0599] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Elimination of cisplatin-resistant lung cancer cells remains a major obstacle. We have shown that cisplatin-resistant tumors have higher reactive oxygen species (ROS) levels and can be exploited for targeted therapy. Here, we show that increased secretion of the antioxidant thioredoxin-1 (TRX1) resulted in lowered intracellular TRX1 and contributed to higher ROS in cisplatin-resistant tumors in vivo and in vitro. By reconstituting TRX1 protein in cisplatin-resistant cells, we increased sensitivity to cisplatin but decreased sensitivity to elesclomol (ROS inducer). Conversely, decreased TRX1 protein in parental cells reduced the sensitivity to cisplatin but increased sensitivity to elesclomol. Cisplatin-resistant cells had increased endogenous oxygen consumption and mitochondrial activity but decreased lactic acid production. They also exhibited higher levels of argininosuccinate synthetase (ASS) and fumarase mRNA, which contributed to oxidative metabolism (OXMET) when compared with parental cells. Restoring intracellular TRX1 protein in cisplatin-resistant cells resulted in lowering ASS and fumarase mRNAs, which in turn sensitized them to arginine deprivation. Interestingly, cisplatin-resistant cells also had significantly higher basal levels of acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS). Overexpressing TRX1 lowered ACC and FAS proteins expressions in cisplatin-resistant cells. Chemical inhibition and short interfering RNA of ACC resulted in significant cell death in cisplatin-resistant compared with parental cells. Conversely, TRX1 overexpressed cisplatin-resistant cells resisted 5-(tetradecyloxy)-2-furoic acid (TOFA)-induced death. Collectively, lowering TRX1 expression through increased secretion leads cisplatin-resistant cells to higher ROS production and increased dependency on OXMET. These changes raise an intriguing therapeutic potential for future therapy in cisplatin-resistant lung cancer.
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Affiliation(s)
| | | | - Chunjing Wu
- Department of Veterans Affairs, South Florida VA Foundation, Miami, FL
| | - Min You
- Department of Medicine, Hematology/Oncology, University of Miami Miller School of Medicine, Miami, FL
| | - Lynn G. Feun
- Department of Medicine, Hematology/Oncology, University of Miami Miller School of Medicine, Miami, FL
| | - Macus T. Kuo
- Department of Molecular Pathology, MD Anderson Cancer Center, Houston, TX
| | - Niramol Savaraj
- Department of Veterans Affairs, South Florida VA Foundation, Miami, FL
- Department of Medicine, Hematology/Oncology, University of Miami Miller School of Medicine, Miami, FL
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150
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Helling S, Hüttemann M, Kadenbach B, Ramzan R, Vogt S, Marcus K. Discovering the phosphoproteome of the hydrophobic cytochrome c oxidase membrane protein complex. Methods Mol Biol 2012; 893:345-358. [PMID: 22665310 DOI: 10.1007/978-1-61779-885-6_21] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Many cellular processes are regulated by reversible phosphorylation to change the activity state of proteins. One example is cytochrome c oxidase (COX) with its important function for energy metabolism in the mitochondria. The phosphorylation of this enzyme is a prerequisite for the allosteric ATP-inhibition and therefore necessary to adapt energy production to ATP demand of the cell. Its hydrophobic nature hampers the recognition of phosphorylated amino acids in most subunits of this complex, and as a consequence, only a few phosphorylation sites were identified by mass spectrometry. We describe here a method that enables the analysis of integral membrane proteins by chemical cleavage with cyanogen bromide (BrCN), a method that improves the mass spectrometric detection of hydrophobic proteins. The low abundance of phosphopeptides requires efficient enrichment techniques, such as TiO(2)-based methods. However, this strategy failed in our hands when just BrCN-cleaved peptides were used. Only an additional size-reduction with trypsin produced peptides with optimal properties for enrichment and MS-identification. Another bottleneck was the correct assignment of phosphoserine and phosphothreonine because peptide-ion fragmentation by collision induced dissociation (CID) often results in neutral loss of HPO(3) or H(2)PO(4) from the precursor, decreasing fragmentations that define the peptide sequence and the phosphorylation site. The additional usage of electron transfer dissociation (ETD) as an alternative fragmentation method enabled the precise assignment of the phosphorylated amino acids. In a total of six, new phosphorylation sites of four COX-subunits were identified by this strategy.
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Affiliation(s)
- Stefan Helling
- Department of Functional Proteomics, Medizinisches Proteom-Center, Ruhr-Universität Bochum, Bochum, Germany.
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