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Kennedy S, Williams C, Tsaturian E, Morgan JT. Dexamethasone Impairs ATP Production and Mitochondrial Performance in Human Trabecular Meshwork Cells. Curr Issues Mol Biol 2024; 46:9867-9880. [PMID: 39329939 PMCID: PMC11430611 DOI: 10.3390/cimb46090587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2024] [Revised: 08/30/2024] [Accepted: 08/30/2024] [Indexed: 09/28/2024] Open
Abstract
Mitochondrial damage occurs in human trabecular meshwork (HTM) cells as a result of normal aging and in open angle glaucoma. Using an HTM cell model, we quantified mitochondrial function and ATP generation rates after dexamethasone (Dex) and TGF-β2 treatments, frequently used as in vitro models of glaucoma. Primary HTM cells were assayed for metabolic function using a Seahorse XFp Analyzer. We additionally assessed the mitochondrial copy number and the expression of transcripts associated with mitochondrial biogenesis and oxidative stress regulation. Cells treated with Dex, but not TGF-β2, exhibited a significant decrease in total ATP production and ATP from oxidative phosphorylation relative to that of the control. Dex treatment also resulted in significant decreases in maximal respiration, ATP-linked O2 consumption, and non-mitochondrial O2 consumption. We did not observe significant changes in the level of mitochondrial genomes or mRNA transcripts of genes involved in mitochondrial biogenesis and oxidative stress regulation. Decreased mitochondrial performance and ATP production are consistent with the results of prior studies identifying the effects of Dex on multiple cell types, including HTM cells. Our results are also consistent with in vivo evidence of mitochondrial damage in open-angle glaucoma. Overall, these results demonstrate a decrease in mitochondrial performance in Dex-induced glaucomatous models in vitro, meriting further investigation.
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Affiliation(s)
- Shane Kennedy
- Department of Molecular, Cell and Systems Biology, University of California-Riverside, Riverside, CA 92521, USA
| | - Clayton Williams
- Department of Bioengineering, University of California-Riverside, Riverside, CA 92521, USA
| | - Emily Tsaturian
- Department of Bioengineering, University of California-Riverside, Riverside, CA 92521, USA
| | - Joshua T. Morgan
- Department of Bioengineering, University of California-Riverside, Riverside, CA 92521, USA
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2
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Nikolic A, Fahlbusch P, Wahlers N, Riffelmann NK, Jacob S, Hartwig S, Kettel U, Dille M, Al-Hasani H, Kotzka J, Knebel B. Chronic stress targets mitochondrial respiratory efficiency in the skeletal muscle of C57BL/6 mice. Cell Mol Life Sci 2023; 80:108. [PMID: 36988756 PMCID: PMC10060325 DOI: 10.1007/s00018-023-04761-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 03/10/2023] [Accepted: 03/15/2023] [Indexed: 03/30/2023]
Abstract
Episodes of chronic stress can result in psychic disorders like post-traumatic stress disorder, but also promote the development of metabolic syndrome and type 2 diabetes. We hypothesize that muscle, as main regulator of whole-body energy expenditure, is a central target of acute and adaptive molecular effects of stress in this context. Here, we investigate the immediate effect of a stress period on energy metabolism in Musculus gastrocnemius in our established C57BL/6 chronic variable stress (Cvs) mouse model. Cvs decreased lean body mass despite increased energy intake, reduced circadian energy expenditure (EE), and substrate utilization. Cvs altered the proteome of metabolic components but not of the oxidative phosphorylation system (OXPHOS), or other mitochondrial structural components. Functionally, Cvs impaired the electron transport chain (ETC) capacity of complex I and complex II, and reduces respiratory capacity of the ETC from complex I to ATP synthase. Complex I-OXPHOS correlated to diurnal EE and complex II-maximal uncoupled respiration correlated to diurnal and reduced nocturnal EE. Bioenergetics assessment revealed higher optimal thermodynamic efficiencies (ƞ-opt) of mitochondria via complex II after Cvs. Interestingly, transcriptome and methylome were unaffected by Cvs, thus excluding major contributions to supposed metabolic adaptation processes. In summary, the preclinical Cvs model shows that metabolic pressure by Cvs is initially compensated by adaptation of mitochondria function associated with high thermodynamic efficiency and decreased EE to manage the energy balance. This counter-regulation of mitochondrial complex II may be the driving force to longitudinal metabolic changes of muscle physiological adaptation as the basis of stress memory.
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Affiliation(s)
- Aleksandra Nikolic
- Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes Center at the Heinrich-Heine-University Duesseldorf, Leibniz Center for Diabetes Research, 40225, Duesseldorf, Germany
- German Center for Diabetes Research (DZD), Partner Duesseldorf, 40225, Duesseldorf, Germany
| | - Pia Fahlbusch
- Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes Center at the Heinrich-Heine-University Duesseldorf, Leibniz Center for Diabetes Research, 40225, Duesseldorf, Germany
- German Center for Diabetes Research (DZD), Partner Duesseldorf, 40225, Duesseldorf, Germany
| | - Natalie Wahlers
- Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes Center at the Heinrich-Heine-University Duesseldorf, Leibniz Center for Diabetes Research, 40225, Duesseldorf, Germany
| | - Nele-Kathrien Riffelmann
- Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes Center at the Heinrich-Heine-University Duesseldorf, Leibniz Center for Diabetes Research, 40225, Duesseldorf, Germany
- German Center for Diabetes Research (DZD), Partner Duesseldorf, 40225, Duesseldorf, Germany
| | - Sylvia Jacob
- Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes Center at the Heinrich-Heine-University Duesseldorf, Leibniz Center for Diabetes Research, 40225, Duesseldorf, Germany
| | - Sonja Hartwig
- Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes Center at the Heinrich-Heine-University Duesseldorf, Leibniz Center for Diabetes Research, 40225, Duesseldorf, Germany
- German Center for Diabetes Research (DZD), Partner Duesseldorf, 40225, Duesseldorf, Germany
| | - Ulrike Kettel
- Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes Center at the Heinrich-Heine-University Duesseldorf, Leibniz Center for Diabetes Research, 40225, Duesseldorf, Germany
| | - Matthias Dille
- Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes Center at the Heinrich-Heine-University Duesseldorf, Leibniz Center for Diabetes Research, 40225, Duesseldorf, Germany
| | - Hadi Al-Hasani
- Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes Center at the Heinrich-Heine-University Duesseldorf, Leibniz Center for Diabetes Research, 40225, Duesseldorf, Germany
- German Center for Diabetes Research (DZD), Partner Duesseldorf, 40225, Duesseldorf, Germany
- Medical Faculty Heinrich-Heine-University Düsseldorf, 40225, Düsseldorf, Germany
| | - Jörg Kotzka
- Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes Center at the Heinrich-Heine-University Duesseldorf, Leibniz Center for Diabetes Research, 40225, Duesseldorf, Germany
- German Center for Diabetes Research (DZD), Partner Duesseldorf, 40225, Duesseldorf, Germany
| | - Birgit Knebel
- Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes Center at the Heinrich-Heine-University Duesseldorf, Leibniz Center for Diabetes Research, 40225, Duesseldorf, Germany.
- German Center for Diabetes Research (DZD), Partner Duesseldorf, 40225, Duesseldorf, Germany.
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3
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Casagrande S, Stier A, Monaghan P, Loveland JL, Boner W, Lupi S, Trevisi R, Hau M. Increased glucocorticoid concentrations in early life cause mitochondrial inefficiency and short telomeres. J Exp Biol 2020; 223:jeb222513. [PMID: 32532864 DOI: 10.1242/jeb.222513] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 06/04/2020] [Indexed: 12/13/2022]
Abstract
Telomeres are DNA structures that protect chromosome ends. However, telomeres shorten during cell replication and at critically low lengths can reduce cell replicative potential, induce cell senescence and decrease fitness. Stress exposure, which elevates glucocorticoid hormone concentrations, can exacerbate telomere attrition. This phenomenon has been attributed to increased oxidative stress generated by glucocorticoids ('oxidative stress hypothesis'). We recently suggested that glucocorticoids could increase telomere attrition during stressful periods by reducing the resources available for telomere maintenance through changes in the metabolic machinery ('metabolic telomere attrition hypothesis'). Here, we tested whether experimental increases in glucocorticoid levels affected telomere length and mitochondrial function in wild great tit (Parus major) nestlings during the energy-demanding early growth period. We monitored resulting corticosterone (Cort) concentrations in plasma and red blood cells, telomere lengths and mitochondrial metabolism (metabolic rate, proton leak, oxidative phosphorylation, maximal mitochondrial capacity and mitochondrial inefficiency). We assessed oxidative damage caused by reactive oxygen species (ROS) metabolites as well as the total non-enzymatic antioxidant protection in plasma. Compared with control nestlings, Cort-nestlings had higher baseline corticosterone, shorter telomeres and higher mitochondrial metabolic rate. Importantly, Cort-nestlings showed increased mitochondrial proton leak, leading to a decreased ATP production efficiency. Treatment groups did not differ in oxidative damage or antioxidants. Hence, glucocorticoid-induced telomere attrition is associated with changes in mitochondrial metabolism, but not with ROS production. These findings support the hypothesis that shortening of telomere length during stressful periods is mediated by glucocorticoids through metabolic rearrangements.
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Affiliation(s)
- Stefania Casagrande
- Max Planck Institute for Ornithology, Evolutionary Physiology Group, 82319 Seewiesen, Germany
| | - Antoine Stier
- Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, UK
- Department of Biology, University of Turku, FI-20014 Turku, Finland
| | - Pat Monaghan
- Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Jasmine L Loveland
- Max Planck Institute for Ornithology, Behavioural Genetics and Evolutionary Ecology Group, 82319 Seewiesen, Germany
| | - Winifred Boner
- Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Sara Lupi
- Max Planck Institute for Ornithology, Evolutionary Physiology Group, 82319 Seewiesen, Germany
- Konrad Lorenz Institute of Ethology, University of Veterinary Medicine, Vienna, A-1160 Vienna, Austria
| | - Rachele Trevisi
- Max Planck Institute for Ornithology, Evolutionary Physiology Group, 82319 Seewiesen, Germany
| | - Michaela Hau
- Max Planck Institute for Ornithology, Evolutionary Physiology Group, 82319 Seewiesen, Germany
- Department of Biology, University of Konstanz, D-78464 Konstanz, Germany
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Barekatain R, Nattrass G, Tilbrook AJ, Chousalkar K, Gilani S. Reduced protein diet and amino acid concentration alter intestinal barrier function and performance of broiler chickens with or without synthetic glucocorticoid. Poult Sci 2019; 98:3662-3675. [DOI: 10.3382/ps/pey563] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Accepted: 11/23/2018] [Indexed: 12/13/2022] Open
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Harvey I, Stephenson EJ, Redd JR, Tran QT, Hochberg I, Qi N, Bridges D. Glucocorticoid-Induced Metabolic Disturbances Are Exacerbated in Obese Male Mice. Endocrinology 2018; 159:2275-2287. [PMID: 29659785 PMCID: PMC5946848 DOI: 10.1210/en.2018-00147] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 04/05/2018] [Indexed: 12/16/2022]
Abstract
The purpose of this study was to determine the effects of glucocorticoid-induced metabolic dysfunction in the presence of diet-induced obesity. C57BL/6J adult male lean and diet-induced obese mice were given dexamethasone, and levels of hepatic steatosis, insulin resistance, and lipolysis were determined. Obese mice given dexamethasone had significant, synergistic effects on fasting glucose, insulin resistance, and markers of lipolysis, as well as hepatic steatosis. This was associated with synergistic transactivation of the lipolytic enzyme adipose triglyceride lipase. The combination of chronically elevated glucocorticoids and obesity leads to exacerbations in metabolic dysfunction. Our findings suggest lipolysis may be a key player in glucocorticoid-induced insulin resistance and fatty liver in individuals with obesity.
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Affiliation(s)
- Innocence Harvey
- Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Erin J Stephenson
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
- Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee
| | - JeAnna R Redd
- Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Quynh T Tran
- Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Irit Hochberg
- Institute of Endocrinology, Diabetes and Metabolism, Rambam Health Care Campus, Haifa, Israel
| | - Nathan Qi
- Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, Michigan
| | - Dave Bridges
- Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
- Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee
- Correspondence: Dave Bridges, PhD, Department of Nutritional Sciences, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, Michigan 48109. E-mail:
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Singh AK, Shree S, Chattopadhyay S, Kumar S, Gurjar A, Kushwaha S, Kumar H, Trivedi AK, Chattopadhyay N, Maurya R, Ramachandran R, Sanyal S. Small molecule adiponectin receptor agonist GTDF protects against skeletal muscle atrophy. Mol Cell Endocrinol 2017; 439:273-285. [PMID: 27645900 DOI: 10.1016/j.mce.2016.09.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 08/23/2016] [Accepted: 09/14/2016] [Indexed: 02/02/2023]
Abstract
Skeletal muscle atrophy is a debilitating response to several major diseases, muscle disuse and chronic steroid treatment for which currently no therapy is available. Since adiponectin signaling plays key roles in muscle energetics, we assessed if globular adiponectin (gAd) or the small molecule adiponectin mimetic 6-C-β-D-glucopyranosyl-(2S,3S)-(+)-5,7,3',4'-tetrahydroxydihydroflavonol (GTDF) could ameliorate muscle atrophy. Both GTDF and gAd induced C2C12 myoblast differentiation. GTDF and gAd effectively prevented reduction in myotube area and suppressed the expressions of atrophy markers; atrogin-1 and muscle ring finger protein-1 (MuRF1) in models of steroid, cytokine and starvation -induced muscle atrophy. The protective effects of GTDF and gAd were routed through AMPK and AKT activation and thereby stimulation of PPAR gamma coactivator 1α and inhibition of forkhead box O transcription factors. Finally, GTDF and gAd mitigated dexamethasone-induced muscle atrophy in vivo. Together, our results demonstrate that activating adiponectin signaling may be an effective therapeutic strategy against skeletal muscle atrophy.
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Affiliation(s)
- Abhishek Kumar Singh
- Division of Biochemistry, CSIR-Central Drug Research Institute, 10, Janakipuram Extn, Sitapur Road, Lucknow 226031, India
| | - Sonal Shree
- Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, 10, Janakipuram Extn, Sitapur Road, Lucknow 226031, India
| | - Sourav Chattopadhyay
- Division of Biochemistry, CSIR-Central Drug Research Institute, 10, Janakipuram Extn, Sitapur Road, Lucknow 226031, India; Academy of Scientific and Innovative Research (AcSIR), CSIR- Central Drug Research Institute Campus, 10, Janakipuram Extn, Sitapur Road, Lucknow 226031, India
| | - Sudhir Kumar
- Division of Medicinal and Process Chemistry, CSIR-Central Drug Research Institute, 10, Janakipuram Extn, Sitapur Road, Lucknow 226031, India
| | - Anagha Gurjar
- Division of Biochemistry, CSIR-Central Drug Research Institute, 10, Janakipuram Extn, Sitapur Road, Lucknow 226031, India; Academy of Scientific and Innovative Research (AcSIR), CSIR- Central Drug Research Institute Campus, 10, Janakipuram Extn, Sitapur Road, Lucknow 226031, India
| | - Sapana Kushwaha
- Division of Biochemistry, CSIR-Central Drug Research Institute, 10, Janakipuram Extn, Sitapur Road, Lucknow 226031, India
| | - Harish Kumar
- Division of Biochemistry, CSIR-Central Drug Research Institute, 10, Janakipuram Extn, Sitapur Road, Lucknow 226031, India
| | - Arun Kumar Trivedi
- Division of Biochemistry, CSIR-Central Drug Research Institute, 10, Janakipuram Extn, Sitapur Road, Lucknow 226031, India
| | - Naibedya Chattopadhyay
- Division of Endocrinology, CSIR-Central Drug Research Institute, 10, Janakipuram Extn, Sitapur Road, Lucknow 226031, India
| | - Rakesh Maurya
- Division of Medicinal and Process Chemistry, CSIR-Central Drug Research Institute, 10, Janakipuram Extn, Sitapur Road, Lucknow 226031, India
| | - Ravishankar Ramachandran
- Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, 10, Janakipuram Extn, Sitapur Road, Lucknow 226031, India
| | - Sabyasachi Sanyal
- Division of Biochemistry, CSIR-Central Drug Research Institute, 10, Janakipuram Extn, Sitapur Road, Lucknow 226031, India; Academy of Scientific and Innovative Research (AcSIR), CSIR- Central Drug Research Institute Campus, 10, Janakipuram Extn, Sitapur Road, Lucknow 226031, India.
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7
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Xu F, Wen T, Wang F, Sang W, Zeng N. Protective effect of cinnamicaldehyde in endotoxin poisoning mice. Immunopharmacol Immunotoxicol 2016; 38:455-463. [DOI: 10.1080/08923973.2016.1241260] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Feng Xu
- Department of Pharmacology, College of Pharmacy, Chengdu University of TCM, Chengdu City, Sichuan Province, PR China
| | - Taoqun Wen
- Department of Pharmacology, College of Pharmacy, Chengdu University of TCM, Chengdu City, Sichuan Province, PR China
| | - Feng Wang
- Department of Pharmacology, College of Pharmacy, Chengdu University of TCM, Chengdu City, Sichuan Province, PR China
| | - Wentao Sang
- Department of Pharmacology, College of Pharmacy, Chengdu University of TCM, Chengdu City, Sichuan Province, PR China
| | - Nan Zeng
- Department of Pharmacology, College of Pharmacy, Chengdu University of TCM, Chengdu City, Sichuan Province, PR China
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8
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Liu J, Peng Y, Wang X, Fan Y, Qin C, Shi L, Tang Y, Cao K, Li H, Long J, Liu J. Mitochondrial Dysfunction Launches Dexamethasone-Induced Skeletal Muscle Atrophy via AMPK/FOXO3 Signaling. Mol Pharm 2015; 13:73-84. [DOI: 10.1021/acs.molpharmaceut.5b00516] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jing Liu
- Center
for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical
Information Engineering of Ministry of Education, School of Life Science
and Technology and Frontier Institute of Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China
- Tianjin Key Laboratory of Exercise Physiology and Sports Medicine, Tianjin University of Sport, Tianjin 300381, China
| | - Yunhua Peng
- Center
for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical
Information Engineering of Ministry of Education, School of Life Science
and Technology and Frontier Institute of Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China
- Tianjin Key Laboratory of Exercise Physiology and Sports Medicine, Tianjin University of Sport, Tianjin 300381, China
| | - Xun Wang
- Center
for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical
Information Engineering of Ministry of Education, School of Life Science
and Technology and Frontier Institute of Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China
- Tianjin Key Laboratory of Exercise Physiology and Sports Medicine, Tianjin University of Sport, Tianjin 300381, China
| | - Yingying Fan
- Center
for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical
Information Engineering of Ministry of Education, School of Life Science
and Technology and Frontier Institute of Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China
- Tianjin Key Laboratory of Exercise Physiology and Sports Medicine, Tianjin University of Sport, Tianjin 300381, China
| | - Chuan Qin
- Center
for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical
Information Engineering of Ministry of Education, School of Life Science
and Technology and Frontier Institute of Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China
- Tianjin Key Laboratory of Exercise Physiology and Sports Medicine, Tianjin University of Sport, Tianjin 300381, China
| | - Le Shi
- Center
for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical
Information Engineering of Ministry of Education, School of Life Science
and Technology and Frontier Institute of Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China
- Tianjin Key Laboratory of Exercise Physiology and Sports Medicine, Tianjin University of Sport, Tianjin 300381, China
| | - Ying Tang
- Center
for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical
Information Engineering of Ministry of Education, School of Life Science
and Technology and Frontier Institute of Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China
- Tianjin Key Laboratory of Exercise Physiology and Sports Medicine, Tianjin University of Sport, Tianjin 300381, China
| | - Ke Cao
- Center
for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical
Information Engineering of Ministry of Education, School of Life Science
and Technology and Frontier Institute of Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China
- Tianjin Key Laboratory of Exercise Physiology and Sports Medicine, Tianjin University of Sport, Tianjin 300381, China
| | - Hua Li
- Center
for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical
Information Engineering of Ministry of Education, School of Life Science
and Technology and Frontier Institute of Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China
- Tianjin Key Laboratory of Exercise Physiology and Sports Medicine, Tianjin University of Sport, Tianjin 300381, China
| | - Jiangang Long
- Center
for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical
Information Engineering of Ministry of Education, School of Life Science
and Technology and Frontier Institute of Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China
- Tianjin Key Laboratory of Exercise Physiology and Sports Medicine, Tianjin University of Sport, Tianjin 300381, China
| | - Jiankang Liu
- Center
for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical
Information Engineering of Ministry of Education, School of Life Science
and Technology and Frontier Institute of Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China
- Tianjin Key Laboratory of Exercise Physiology and Sports Medicine, Tianjin University of Sport, Tianjin 300381, China
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9
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Molena-Fernandes C, Bersani-Amado CA, Ferraro ZM, Hintze LJ, Nardo N, Cuman RKN. Effects of exercise and metformin on the prevention of glucose intolerance: a comparative study. Braz J Med Biol Res 2015; 48:1101-8. [PMID: 26421869 PMCID: PMC4661026 DOI: 10.1590/1414-431x20153904] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 04/02/2015] [Indexed: 11/22/2022] Open
Abstract
We aimed to evaluate the effects of aerobic exercise training (4 days) and metformin
exposure on acute glucose intolerance after dexamethasone treatment in rats.
Forty-two adult male Wistar rats (8 weeks old) were divided randomly into four
groups: sedentary control (SCT), sedentary dexamethasone-treated (SDX), training
dexamethasone-treated (DPE), and dexamethasone and metformin treated group (DMT).
Glucose tolerance tests and in situ liver perfusion were undertaken
on fasting rats to obtain glucose profiles. The DPE group displayed a significant
decrease in glucose values compared with the SDX group. Average glucose levels in the
DPE group did not differ from those of the DMT group, so we suggest that exercise
training corrects dexamethasone-induced glucose intolerance and improves glucose
profiles in a similar manner to that observed with metformin. These data suggest that
exercise may prevent the development of glucose intolerance induced by dexamethasone
in rats to a similar magnitude to that observed after metformin treatment.
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Affiliation(s)
- C Molena-Fernandes
- Colegiado de Educação Física, Universidade Estadual do Paraná, Paranavaí, PR, Brasil
| | - C A Bersani-Amado
- Departamento de Farmácia e Farmacologia, Universidade Estadual de Maringá, Maringá, PR, Brasil
| | - Z M Ferraro
- Healthy Active Living and Obesity Research Group, Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | - L J Hintze
- Departamento de Educação Física, Universidade Estadual de Maringá, Maringá, PR, Brasil
| | - N Nardo
- Healthy Active Living and Obesity Research Group, Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | - R K N Cuman
- Departamento de Farmácia e Farmacologia, Universidade Estadual de Maringá, Maringá, PR, Brasil
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Salin K, Roussel D, Rey B, Voituron Y. David and goliath: a mitochondrial coupling problem? ACTA ACUST UNITED AC 2015; 317:283-93. [PMID: 25363578 DOI: 10.1002/jez.1722] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 02/01/2012] [Accepted: 02/02/2012] [Indexed: 11/10/2022]
Abstract
An organism's size, known to affect biological structures and processes from cellular metabolism to population dynamics, depends upon the duration and rate of growth. However, it is still poorly understood how mitochondrial function affects the energetic basis of growth, especially in ectotherms, which represent a huge majority of animal biodiversity. Here, we present an intraspecies comparison of neighboring populations of frogs (Rana temporaria) that have large differences in body mass even at the same age. By investigating liver mitochondrial bioenergetics, we find that frogs with high growth rates and large body sizes exhibit higher ATP synthesis rates and more efficient oxidative phosphorylation compared to the smaller frogs with low growth rates. This higher energy transduction efficiency is not associated with significant increased oxidative capacity or membrane potential values, but instead may rely on a higher mitochondrial phosphorylation system activity in combination with a lower inner membrane proton leakage. Overall, the present study introduces the mitochondrial energy transduction system as an important mechanism for balancing physiological and ecological trade-offs associated with body size. Whether phenotype differences in mitochondrial function result from local ecological constraints or reflect a natural genetic variability within wild populations of common frogs remains an open question. However, our findings highlight the need for closer consideration of all aspects of mitochondrial metabolism for a better understanding of the physiological basis of the link between size, metabolism, and energy production in wild-dwelling organisms.
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Affiliation(s)
- Karine Salin
- Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés (U.M.R. CNRS 5023), Université Claude Bernard Lyon 1, Université de Lyon, Villeurbanne, France
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Cardiolipin content is involved in liver mitochondrial energy wasting associated with cancer-induced cachexia without the involvement of adenine nucleotide translocase. Biochim Biophys Acta Mol Basis Dis 2014; 1842:726-33. [PMID: 24534708 DOI: 10.1016/j.bbadis.2014.02.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 02/05/2014] [Accepted: 02/09/2014] [Indexed: 11/21/2022]
Abstract
Cancer-induced cachexia describes the progressive skeletal muscle wasting associated with many cancers leading to shortened survival time in cancer patients. We previously reported that cardiolipin content and energy-wasting processes were both increased in liver mitochondria in a rat model of peritoneal carcinosis (PC)-induced cachexia. To increase the understanding of the cellular biology of cancer cachexia, we investigated the involvement of adenine nucleotide translocator (ANT) in mitochondrial energy-wasting processes in liver mitochondria of PC and pair-fed control rats and its interactions with cardiolipin in isolated liver mitochondria from healthy rats exposed to cardiolipin-enriched liposomes. We showed in this study that functional ANT content was decreased in liver mitochondria from PC rats but without any effects on the efficiency of ATP synthesis. Moreover, non-phosphorylating energy wasting was not affected by saturating concentrations of carboxyatractylate (CAT), a potent inhibitor of ANT, in liver mitochondria from PC rats. Decreased efficiency of ATP synthesis was found in normal liver mitochondria exposed to cardiolipin-enriched liposomes, with increased non-phosphorylating energy wasting, thus mimicking mitochondria from PC rats. However, the functional ANT content in these cardiolipin-enriched mitochondria was unchanged, although non-phosphorylating energy wasting was reduced by CAT-induced inhibition of ANT. Finally, non-phosphorylating energy wasting was increased in cardiolipin-enriched mitochondria with substrates for complexes 1 and 2, but not for complex 4. In conclusion, increased energy wasting measured in liver mitochondria from rats with cancer cachexia is dependent on cardiolipin but independent of ANT. Interactions between ANT and cardiolipin are modified when cancer cachexia occurs.
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Vrana JA, Boggs N, Currie HN, Boyd J. Amelioration of an undesired action of deguelin. Toxicon 2013; 74:83-91. [PMID: 23933198 DOI: 10.1016/j.toxicon.2013.07.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 07/22/2013] [Accepted: 07/30/2013] [Indexed: 01/09/2023]
Abstract
The pharmaceutical world has greatly benefited from the well-characterized structure-function relationships of toxins with endogenous biomolecules, such as ion-channels, receptors, and signaling molecules. Thus, therapeutics derived from toxins have been aggressively pursued. However, the multifunctional role of various toxins may lead to undesirable off-target effects, hindering their use as therapeutic agents. In this paper, we suggest that previously unsuccessful toxins (due to off-target effects) may be revisited with mixtures by utilizing the pharmacodynamic response to the potential primary therapeutic as a starting point for finding new targets to ameliorate the unintended responses. In this proof of principle study, the pharmacodynamic response of HepG2 cells to a potential primary therapeutic (deguelin, a plant-derived chemopreventive agent) was monitored, and a possible secondary target (p38MAPK) was identified. As a single agent, deguelin decreased cellular viability at higher doses (>10 μM), but inhibited oxygen consumption over a wide dosing range (1.0-100 μM). Our results demonstrate that inhibition of oxygen consumption is related to an increase in p38MAPK phosphorylation, and may only be an undesired side effect of deguelin (i.e., one that does not contribute to the decrease in HepG2 viability). We further show that deguelin's negative effect on oxygen consumption can be diminished while maintaining efficacy when used as a therapeutic mixture with the judiciously selected secondary inhibitor (SB202190, p38MAPK inhibitor). These preliminary findings suggest that an endogenous response-directed mixtures approach, which uses a pharmacodynamic response to a primary therapeutic to determine a secondary target, allows previously unsuccessful toxins to be revisited as therapeutic mixtures.
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Affiliation(s)
- Julie A Vrana
- C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Prospect Street, P.O. Box 6045, Morgantown, WV 26506, United States
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Hernández-Alvarez MI, Paz JC, Sebastián D, Muñoz JP, Liesa M, Segalés J, Palacín M, Zorzano A. Glucocorticoid modulation of mitochondrial function in hepatoma cells requires the mitochondrial fission protein Drp1. Antioxid Redox Signal 2013; 19:366-78. [PMID: 22703557 PMCID: PMC3700019 DOI: 10.1089/ars.2011.4269] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
AIMS Glucocorticoids, such as dexamethasone, enhance hepatic energy metabolism and gluconeogenesis partly through changes in mitochondrial function. Mitochondrial function is influenced by the balance between mitochondrial fusion and fission events. However, whether glucocorticoids modulate mitochondrial function through the regulation of mitochondrial dynamics is currently unknown. RESULTS Here, we report that the effects of dexamethasone on mitochondrial function and gluconeogenesis in hepatoma cells are dependent on the mitochondrial fission protein dynamin-related protein 1 (Drp1). Dexamethasone increased routine oxygen consumption, maximal respiratory capacity, superoxide anion, proton leak, and gluconeogenesis in hepatoma cells. Under these conditions, dexamethasone altered mitochondrial morphology, which was paralleled by a large increase in Drp1 expression, and reduced mitofusin 1 (Mfn1) and Mfn2. In vivo dexamethasone treatment also enhanced Drp1 expression in mouse liver. On the basis of these observations, we analyzed the dependence on the Drp1 function of dexamethasone effects on mitochondrial respiration and gluconeogenesis. We show that the increase in mitochondrial respiration and gluconeogenesis induced by dexamethasone are hampered by the inhibition of Drp1 function. INNOVATION Our findings provide the first evidence that the effects of glucocorticoids on hepatic metabolism require the mitochondrial fission protein Drp1. CONCLUSION In summary, we demonstrate that the mitochondrial effects of dexamethasone both on mitochondrial respiration and on the gluconeogenic pathway depend on Drp1.
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Ashraf S, Mapp PI, Walsh DA. Contributions of angiogenesis to inflammation, joint damage, and pain in a rat model of osteoarthritis. ACTA ACUST UNITED AC 2011; 63:2700-10. [PMID: 21538326 DOI: 10.1002/art.30422] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVE To determine the contributions of angiogenesis to inflammation, joint damage, and pain behavior in a rat meniscal transection model of osteoarthritis (OA). METHODS OA was induced in male Lewis rats (n=8 per group) by meniscal transection. Animals were orally dosed with dexamethasone (0.1 mg/kg/day), indomethacin (2 mg/kg/day), or the specific angiogenesis inhibitor PPI-2458 (5 mg/kg every other day). Controls consisted of naive and vehicle-treated rats. Synovial inflammation was measured as the macrophage fractional area (expressed as the percentage), thickness of the synovial lining, and joint swelling. Synovial angiogenesis was measured using the endothelial cell proliferation index and vascular density. Channels positive for vessels at the osteochondral junction were assessed (osteochondral angiogenesis). Medial tibial plateaus were assessed for chondropathy, osteophytosis, and channels crossing the osteochondral junction. Pain behavior was measured as weight-bearing asymmetry. RESULTS Dexamethasone and indomethacin each reduced pain behavior, synovial inflammation, and synovial angiogenesis 35 days after meniscal transection. Dexamethasone reduced, but indomethacin had no significant effect on, the total joint damage score. PPI-2458 treatment reduced synovial and osteochondral angiogenesis, synovial inflammation, joint damage, and pain behavior. CONCLUSION Our findings indicate that synovial inflammation and joint damage are closely associated with pain behavior in the meniscal transection model of OA. Inhibition of angiogenesis may reduce pain behavior both by reducing synovitis and by preventing structural change. Targeting angiogenesis could therefore prove useful in reducing pain and structural damage in OA.
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Affiliation(s)
- Sadaf Ashraf
- Arthritis Research UK Pain Centre, Department of Academic Rheumatology, University of Nottingham, City Hospital, Nottingham, UK.
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Ducluzeau PH, Priou M, Weitheimer M, Flamment M, Duluc L, Iacobazi F, Soleti R, Simard G, Durand A, Rieusset J, Andriantsitohaina R, Malthièry Y. Dynamic regulation of mitochondrial network and oxidative functions during 3T3-L1 fat cell differentiation. J Physiol Biochem 2011; 67:285-96. [PMID: 21267801 DOI: 10.1007/s13105-011-0074-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Accepted: 01/07/2011] [Indexed: 12/13/2022]
Abstract
Mitochondria have been shown to be impaired in insulin resistance-related diseases but have not been extensively studied during the first steps of adipose cell development. This study was designed to determine the sequence of changes of the mitochondrial network and function during the first days of adipogenesis. 3T3-L1 preadipocytes were differentiated into adipocytes without using glitazone compounds. At days 0, 3, 6, 9, and 12, mitochondrial network imaging, mitochondrial oxygen consumption, membrane potential, and oxidative phosphorylation efficiency were assessed in permeabilized cells. Gene and protein expressions related to fatty acid metabolism and mitochondrial network were also determined. Compared to preadipocytes (day 0), new adipocytes (days 6 and 9) displayed profound changes of their mitochondrial network that underwent fragmentation and redistribution around lipid droplets. Drp1 and mitofusin 2 displayed a progressive increase in their gene expression and protein content during the first 9 days of differentiation. In parallel with the mitochondrial network redistribution, mitochondria switched to uncoupled respiration with a tendency towards decreased membrane potential, with no variation of mtTFA and NRF1 gene expression. The expression of PGC1α and NRF2 genes and genes involved in lipid oxidation (UCP2, CD36, and CPT1) was increased. Reactive oxygen species (ROS) production displayed a nadir at day 6 with a concomitant increase in antioxidant enzyme gene expression. This 3T3-L1-based in vitro model of adipogenesis showed that mitochondria adapted to the increased number of lipid droplets by network redistribution and uncoupling respiration. The timing and regulation of lipid oxidation-associated ROS production appeared to play an important role in these changes.
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Dumas JF, Goupille C, Pinault M, Fandeur L, Bougnoux P, Servais S, Couet C. N-3 PUFA-Enriched Diet Delays the Occurrence of Cancer Cachexia in Rat With Peritoneal Carcinosis. Nutr Cancer 2010; 62:343-50. [DOI: 10.1080/01635580903407080] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Hadsell D, George J, Abraham P, Collier R, Lambert B. Technical note: Assessing the functional capacity of mitochondria isolated from lactating mammary tissue: Choose your chelating agent wisely. J Dairy Sci 2009; 92:2038-45. [DOI: 10.3168/jds.2008-1360] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Arvier M, Lagoutte L, Johnson G, Dumas JF, Sion B, Grizard G, Malthièry Y, Simard G, Ritz P. Adenine nucleotide translocator promotes oxidative phosphorylation and mild uncoupling in mitochondria after dexamethasone treatment. Am J Physiol Endocrinol Metab 2007; 293:E1320-4. [PMID: 17698987 DOI: 10.1152/ajpendo.00138.2007] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The composition of the mitochondrial inner membrane and uncoupling protein [such as adenine nucleotide translocator (ANT)] contents are the main factors involved in the energy-wasting proton leak. This leak is increased by glucocorticoid treatment under nonphosphorylating conditions. The aim of this study was to investigate mechanisms involved in glucocorticoid-induced proton leak and to evaluate the consequences in more physiological conditions (between states 4 and 3). Isolated liver mitochondria, obtained from dexamethasone-treated rats (1.5 mg.kg(-1).day(-1)), were studied by polarography, Western blotting, and high-performance thin-layer chromatography. We confirmed that dexamethasone treatment in rats induces a proton leak in state 4 that is associated with an increased ANT content, although without any change in membrane surface or lipid composition. Between states 4 and 3, dexamethasone stimulates ATP synthesis by increasing both the mitochondrial ANT and F1-F0 ATP synthase content. In conclusion, dexamethasone increases mitochondrial capacity to generate ATP by modifying ANT and ATP synthase. The side effect is an increased leak in nonphosphorylating conditions.
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Affiliation(s)
- Matthieu Arvier
- Institut National de la Santé et de la Recherche Médicale, Laboratoire de Biochimie et de Biologie Moléculaire, Centre Hospitalier Universitaire, Angers, France
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Dumas JF, Simard G, Roussel D, Douay O, Foussard F, Malthiery Y, Ritz P. Mitochondrial energy metabolism in a model of undernutrition induced by dexamethasone. Br J Nutr 2007; 90:969-77. [PMID: 14667190 PMCID: PMC1952694 DOI: 10.1079/bjn2003980] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The present investigation was undertaken to evaluate whether mitochondrial energy metabolism is altered in a model of malnutrition induced by dexamethasone (DEX) treatment (1·5mg/kg per d for 5d). The gastrocnemius and liver mitochondria were isolated from DEX-treated, pair-fed (PF) and control (CON) rats. Body weight was reduced significantly more in the DEX-treated group (−16%) than in the PF group (−9%). DEX treatment increased liver mass (+59%v.PF, +23%v. CON) and decreased gastrocnemius mass. Moreover, in DEX-treated rats, liver mitochondria had an increased rate of non-phosphorylative O2consumption with all substrates (approximately +42%). There was no difference in enzymatic complex activities in liver mitochondria between rat groups. Collectively, these results suggest an increased proton leak and/or redox slipping in the liver mitochondria of DEX-treated rats. In addition, DEX decreased the thermodynamic coupling and efficiency of oxidative phosphorylation. We therefore suggest that this increase in the proton leak and/or redox slip in the liver is responsible for the decrease in the thermodynamic efficiency of energy conversion. In contrast, none of the variables of energy metabolism determined in gastrocnemius mitochondria was altered by DEX treatment. Therefore, it appears that DEX specifically affects mitochondrial energy metabolism in the liver.
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Caparroz-Assef SM, Bersani-Amado CA, Kelmer-Bracht AM, Bracht A, Ishii-Iwamoto EL. The metabolic changes caused by dexamethasone in the adjuvant-induced arthritic rat. Mol Cell Biochem 2007; 302:87-98. [PMID: 17347874 DOI: 10.1007/s11010-007-9430-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2006] [Accepted: 02/09/2007] [Indexed: 11/26/2022]
Abstract
The action of orally administered dexamethasone (0.2 mg kg(-1) day(-1)) on metabolic parameters of adjuvant-induced arthritic rats was investigated. The body weight gain and the progression of the disease were also monitored. Dexamethasone was very effective in suppressing the Freund's adjuvant-induced paw edema and the appearance of secondary lesions. In contrast, the body weight loss of dexamethasone-treated arthritic rats was more accentuated than that of untreated arthritic or normal rats treated with dexamethasone, indicating additive harmful effects. The perfused livers from dexamethasone-treated arthritic rats presented high content of glycogen in both fed and fasted conditions, as indicated by the higher rates of glucose release in the absence of exogenous substrate. The metabolization of exogenous L: -alanine was increased in livers from dexamethasone-treated arthritic rats in comparison with untreated arthritic rats, but there was a diversion of carbon flux from glucose to L: -lactate and pyruvate. Plasmatic levels of insulin and glucose were significantly higher in arthritic rats following dexamethasone administration. Most of these changes were also found in livers from normal rats treated with dexamethasone. The observed changes in L: -alanine metabolism and glycogen synthesis indicate that insulin was the dominant hormone in the regulation of the liver glucose metabolism even in the fasting condition. The prevalence of the metabolic effects of dexamethasone over those ones induced by the arthritis disease suggests that dexamethasone administration was able to suppress the mechanisms implicated in the development of the arthritis-induced hepatic metabolic changes. It seems thus plausible to assume that those factors responsible for the inflammatory responses in the paws and for the secondary lesions may be also implicated in the liver metabolic changes, but not in the body weight loss of arthritic rats.
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Affiliation(s)
- Silvana M Caparroz-Assef
- Laboratory of Liver Metabolism, Department of Biochemistry, University of Maringá, 87020900 Maringá, Brazil
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Ritz P, Berrut G. Mitochondrial function, energy expenditure, aging and insulin resistance. DIABETES & METABOLISM 2005; 31 Spec No 2:5S67-5S73. [PMID: 16415768 DOI: 10.1016/s1262-3636(05)73654-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Mitochondria are the cells' powerhouse that produce the ubiquitous energy currency (ATP) by consuming oxygen, producing water and building up the proton motive force. Oxygen consumption is a classical means of assessing energy expenditure, one component of energy balance. When energy balance is positive, weight increases. This is observed during the dynamic phase of obesity, and during body composition changes associated with aging. Whether intrinsic defaults in mitochondria occur is the matter of this review. Indeed, the ratio of ATP over oxygen consumed, which is not fixed, is one way of regulating heat release and ATP flux, but can also be the consequence of environmental conditions of mitochondrial work. For example, various hormones (T3, glucocorticoids), changes in lipid membrane composition, changes in food intake and exercise, and various drugs, can modify the ratio of ATP over oxygen consumed. Aging and insulin resistance are other regulators of this ratio. Finally there is a rising body of evidence linking diabetes to mitochondrial functions.
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Affiliation(s)
- P Ritz
- INSERM UMR 694, Pôle médecine interne et maladies métaboliques, Angers, France.
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Abstract
PURPOSE OF REVIEW It had been thought for a long time that thyroid hormones were the only ones to regulate energy production within mitochondria. Recent findings show that other hormones (steroids, leptin, insulin) regulate the efficiency of mitochondrial adenosine triphosphate production. Furthermore, a mismatch between oxygen consumption and energy intake may not be sufficient to understand body weight regulation. It appears that the efficiency of adenosine triphosphate production may play a role. RECENT FINDINGS Over the past 2 years a series of results argued that glucocorticoids influence energy balance, the efficiency of adenosine triphosphate production, and are thermogenic. The sites for this effect are discussed, probably both the liver and muscle. Evidence of the genes involved in this regulation is substantial for muscle but remains to be studied in the liver. On the other hand, leptin could be a thermogenic hormone, especially in situations of calorie restriction. Finally, recent data and opinions suggest that mitochondria and adenosine triphosphate production could be central in the pathogenesis of both insulin resistance and beta cell deficiency. SUMMARY The adaptation of mitochondrial adenosine triphosphate production appears to play a role in both diabetes and weight loss (voluntary and involuntary). Hormonal and nutritional manipulation could be a therapeutic possibility for weight management.
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Roussel D, Dumas JF, Simard G, MALTHIèRY Y, Ritz P. Kinetics and control of oxidative phosphorylation in rat liver mitochondria after dexamethasone treatment. Biochem J 2005; 382:491-9. [PMID: 15175015 PMCID: PMC1133805 DOI: 10.1042/bj20040696] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2004] [Revised: 05/25/2004] [Accepted: 06/03/2004] [Indexed: 01/07/2023]
Abstract
The present investigation was undertaken in order to evaluate the contributions of ATP synthesis and proton leak reactions to the rate of active respiration of liver mitochondria, which is altered following dexamethasone treatment (1.5 mg/kg per day for 5 days). We applied top-down metabolic control analysis and its extension, elasticity analysis, to gain insight into the mechanisms of glucocorticoid regulation of mitochondrial bioenergetics. Liver mitochondria were isolated from dexamethasone-treated, pair-fed and control rats when in a fed or overnight fasted state. Injection of dexamethasone for 5 days resulted in an increase in the fraction of the proton cycle of phosphorylating liver mitochondria, which was associated with a decrease in the efficiency of the mitochondrial oxidative phosphorylation process in liver. This increase in proton leak activity occurred with little change in the mitochondrial membrane potential, despite a significant decrease in the rate of oxidative phosphorylation. Regulation analysis indicates that mitochondrial membrane potential homoeostasis is achieved by equal inhibition of the mitochondrial substrate oxidation and phosphorylation reactions in rats given dexamethasone. Our results also suggest that active liver mitochondria from dexamethasone-treated rats are capable of maintaining phosphorylation flux for cellular purposes, despite an increase in the energetic cost of mitochondrial ATP production due to increased basal proton permeability of the inner membrane. They also provide a complete description of the effects of dexamethasone treatment on liver mitochondrial bioenergetics.
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Affiliation(s)
- Damien Roussel
- Laboratoire de Biochimie et Biologie Moléculaire, INSERM EMI-U 00.18, 4 rue Larrey, F-49033 Angers cedex, France
- To whom correspondence should be addressed (email )
| | - Jean-François Dumas
- Laboratoire de Biochimie et Biologie Moléculaire, INSERM EMI-U 00.18, 4 rue Larrey, F-49033 Angers cedex, France
| | - Gilles Simard
- Laboratoire de Biochimie et Biologie Moléculaire, INSERM EMI-U 00.18, 4 rue Larrey, F-49033 Angers cedex, France
| | - Yves MALTHIèRY
- Laboratoire de Biochimie et Biologie Moléculaire, INSERM EMI-U 00.18, 4 rue Larrey, F-49033 Angers cedex, France
| | - Patrick Ritz
- Laboratoire de Biochimie et Biologie Moléculaire, INSERM EMI-U 00.18, 4 rue Larrey, F-49033 Angers cedex, France
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Dumas JF, Bielicki G, Renou JP, Roussel D, Ducluzeau PH, Malthièry Y, Simard G, Ritz P. Dexamethasone impairs muscle energetics, studied by (31)P NMR, in rats. Diabetologia 2005; 48:328-35. [PMID: 15645207 DOI: 10.1007/s00125-004-1631-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2004] [Accepted: 08/09/2004] [Indexed: 01/06/2023]
Abstract
AIMS/HYPOTHESIS Glucocorticoid treatments are associated with increased whole-body oxygen consumption. We hypothesised that an impairment of muscle energy metabolism can participate in this increased energy expenditure. METHODS To investigate this possibility, we have studied muscle energetics of dexamethasone-treated rats (1.5 mg kg(-1) day(-1) for 6 days), in vivo by (31)P NMR spectroscopy. Results were compared with control and pair-fed (PF) rats before and after overnight fasting. RESULTS Dexamethasone treatment resulted in decreased phosphocreatine (PCr) concentration and PCr:ATP ratio, increased ADP concentration and higher PCr to gamma-ATP flux but no change in beta-ATP to beta-ADP flux in gastrocnemius muscle. Neither 4 days of food restriction (PF rats) nor 24 h fasting affected high-energy phosphate metabolism. In dexamethasone-treated rats, there was an increase in plasma insulin and non-esterified fatty acid concentration. CONCLUSIONS/INTERPRETATION We conclude that dexamethasone treatment altered resting in vivo skeletal muscle energy metabolism, by decreasing oxidative phosphorylation, producing ATP at the expense of PCr.
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Affiliation(s)
- J-F Dumas
- Inserm EMI-U 00.18, Laboratoire de Biochimie et de Biologie Moléculaire, CHU, 4 rue Larrey, 49033 Angers Cedex, France
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