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Wilkinson MGL, Moulding D, McDonnell TCR, Orford M, Wincup C, Ting JYJ, Otto GW, Restuadi R, Kelberman D, Papadopoulou C, Castellano S, Eaton S, Deakin CT, Rosser EC, Wedderburn LR. Role of CD14+ monocyte-derived oxidised mitochondrial DNA in the inflammatory interferon type 1 signature in juvenile dermatomyositis. Ann Rheum Dis 2023; 82:658-669. [PMID: 36564154 PMCID: PMC10176342 DOI: 10.1136/ard-2022-223469] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 12/01/2022] [Indexed: 12/25/2022]
Abstract
OBJECTIVES To define the host mechanisms contributing to the pathological interferon (IFN) type 1 signature in Juvenile dermatomyositis (JDM). METHODS RNA-sequencing was performed on CD4+, CD8+, CD14+ and CD19+ cells sorted from pretreatment and on-treatment JDM (pretreatment n=10, on-treatment n=11) and age/sex-matched child healthy-control (CHC n=4) peripheral blood mononuclear cell (PBMC). Mitochondrial morphology and superoxide were assessed by fluorescence microscopy, cellular metabolism by 13C glucose uptake assays, and oxidised mitochondrial DNA (oxmtDNA) content by dot-blot. Healthy-control PBMC and JDM pretreatment PBMC were cultured with IFN-α, oxmtDNA, cGAS-inhibitor, TLR-9 antagonist and/or n-acetyl cysteine (NAC). IFN-stimulated gene (ISGs) expression was measured by qPCR. Total numbers of patient and controls for functional experiments, JDM n=82, total CHC n=35. RESULTS Dysregulated mitochondrial-associated gene expression correlated with increased ISG expression in JDM CD14+ monocytes. Altered mitochondrial-associated gene expression was paralleled by altered mitochondrial biology, including 'megamitochondria', cellular metabolism and a decrease in gene expression of superoxide dismutase (SOD)1. This was associated with enhanced production of oxidised mitochondrial (oxmt)DNA. OxmtDNA induced ISG expression in healthy PBMC, which was blocked by targeting oxidative stress and intracellular nucleic acid sensing pathways. Complementary experiments showed that, under in vitro experimental conditions, targeting these pathways via the antioxidant drug NAC, TLR9 antagonist and to a lesser extent cGAS-inhibitor, suppressed ISG expression in pretreatment JDM PBMC. CONCLUSIONS These results describe a novel pathway where altered mitochondrial biology in JDM CD14+ monocytes lead to oxmtDNA production and stimulates ISG expression. Targeting this pathway has therapeutical potential in JDM and other IFN type 1-driven autoimmune diseases.
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Affiliation(s)
- Meredyth G Ll Wilkinson
- Infection, Immunity and Inflammation Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK
- Centre for Adolescent Rheumatology Versus Arthritis at UCL UCLH and GOSH, UCL, London, UK
- NIHR Biomedical Research Centre, Great Ormond Street Hospital, London, UK
| | - Dale Moulding
- NIHR Biomedical Research Centre, Great Ormond Street Hospital, London, UK
- Developmental Biology and Cancer Research & Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Thomas C R McDonnell
- Centre for Rheumatology Research, Division of Medicine, University College London, London, UK
| | - Michael Orford
- Developmental Biology and Cancer Research & Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Chris Wincup
- Centre for Rheumatology Research, Division of Medicine, University College London, London, UK
| | - Joanna Y J Ting
- Infection, Immunity and Inflammation Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Georg W Otto
- NIHR Biomedical Research Centre, Great Ormond Street Hospital, London, UK
- Experimental and Personalised Medicine, Genetics and Genomic Medicine, UCL Great Ormond Street Institute of Child Health, London, UK
- Genetics and Genomic Medicine Research & Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Restuadi Restuadi
- Infection, Immunity and Inflammation Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK
- Centre for Adolescent Rheumatology Versus Arthritis at UCL UCLH and GOSH, UCL, London, UK
- NIHR Biomedical Research Centre, Great Ormond Street Hospital, London, UK
| | - Daniel Kelberman
- NIHR Biomedical Research Centre, Great Ormond Street Hospital, London, UK
- Experimental and Personalised Medicine, Genetics and Genomic Medicine, UCL Great Ormond Street Institute of Child Health, London, UK
- Genetics and Genomic Medicine Research & Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Charalampia Papadopoulou
- Infection, Immunity and Inflammation Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK
- Rheumatology, Great Ormond Street Hospital NHS Trust, London, UK
| | - Sergi Castellano
- NIHR Biomedical Research Centre, Great Ormond Street Hospital, London, UK
- Genetics and Genomic Medicine Research & Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Simon Eaton
- NIHR Biomedical Research Centre, Great Ormond Street Hospital, London, UK
- Developmental Biology and Cancer Research & Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Claire T Deakin
- Infection, Immunity and Inflammation Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK
- Centre for Adolescent Rheumatology Versus Arthritis at UCL UCLH and GOSH, UCL, London, UK
- NIHR Biomedical Research Centre, Great Ormond Street Hospital, London, UK
| | - Elizabeth C Rosser
- Centre for Adolescent Rheumatology Versus Arthritis at UCL UCLH and GOSH, UCL, London, UK
- Centre for Rheumatology Research, Division of Medicine, University College London, London, UK
| | - Lucy R Wedderburn
- Infection, Immunity and Inflammation Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK
- Centre for Adolescent Rheumatology Versus Arthritis at UCL UCLH and GOSH, UCL, London, UK
- NIHR Biomedical Research Centre, Great Ormond Street Hospital, London, UK
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Dias PRF, Gandra PG, Brenzikofer R, Macedo DV. Subcellular fractionation of frozen skeletal muscle samples. Biochem Cell Biol 2019; 98:293-298. [PMID: 31608669 DOI: 10.1139/bcb-2019-0219] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cell fractionation can be used to determine the localization and trafficking of proteins between cellular compartments such as the cytosol, mitochondria, and nuclei. Subcellular fractionation is usually performed immediately after tissue dissection because freezing may fragment cell membranes and induce organellar cross-contamination. Mitochondria are especially sensitive to freezing/thawing and mechanical homogenization. We proposed a protocol to improve the retention of soluble proteins in the mitochondrial fraction obtained from small amounts of frozen skeletal muscle. Fifty milligrams of the red portion of gastrocnemius muscle from Wistar rats were immediately processed or frozen in liquid nitrogen and stored at -80 °C for further processing. We compared the enrichment of subcellular fractions from frozen/fresh samples obtained with the modified protocol with those obtained by standard fractionation. Western blot analyses of marker proteins for cytosolic (alpha-tubulin), mitochondrial (VDAC1), and nuclear (histone-H3) fractions indicated that all of the procedures resulted in enriched subcellular fractions with minimal organellar cross-contamination. Notably, the activity of the soluble protein citrate synthase was higher in the mitochondrial fractions obtained with the modified protocol from frozen/fresh samples compared with the standard protocol. Therefore, our protocol improved the retention of soluble proteins in the mitochondrial fraction and may be suitable for subcellular fractionation of small amounts of frozen skeletal muscle samples.
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Affiliation(s)
- Pedro Rafael Firmino Dias
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Paulo Guimarães Gandra
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - René Brenzikofer
- School of Physical Education, University of Campinas, Campinas, Brazil
| | - Denise Vaz Macedo
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, Brazil
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3
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Lai N, M. Kummitha C, Rosca MG, Fujioka H, Tandler B, Hoppel CL. Isolation of mitochondrial subpopulations from skeletal muscle: Optimizing recovery and preserving integrity. Acta Physiol (Oxf) 2019; 225:e13182. [PMID: 30168663 DOI: 10.1111/apha.13182] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 08/24/2018] [Accepted: 08/27/2018] [Indexed: 12/11/2022]
Abstract
AIM The subsarcolemmal (SSM) and interfibrillar (IFM) mitochondria in skeletal muscle appear to have distinct biochemical properties affecting metabolism in health and disease. The isolation of mitochondrial subpopulations has been a long-time challenge while the presence of a continuous mitochondrial reticulum challenges the view of distinctive SSM and IFM bioenergetics. Here, a comprehensive approach is developed to identify the best conditions to separate mitochondrial fractions. METHODS The main modifications to the protocol to isolate SSM and IFM from rat skeletal muscle were: (a) decreased dispase content and homogenization speed; (b) trypsin treatment of SSM fractions; (c) recentrifugation of mitochondrial fractions at low speed to remove subcellular components. To identify the conditions preserving mitochondrial function, integrity, and maximizing their recovery, microscopy (light and electron) were used to monitor effectiveness and efficiency in separating mitochondrial subpopulations while respiratory and enzyme activities were employed to evaluate function, recovery, and integrity. RESULTS With the modifications described, the total mitochondrial yield increased with a recovery of 80% of mitochondria contained in the original skeletal muscle sample. The difference between SSM and IFM oxidative capacity (10%) with complex-I substrate was significant only with a saturated ADP concentration. The inner and outer membrane damage for both subpopulations was <1% and 8%, respectively, while the respiratory control ratio was 16. CONCLUSION Using a multidisciplinary approach, conditions were identified to maximize SSM and IFM recovery while preserving mitochondrial integrity, biochemistry, and morphology. High quality and recovery of mitochondrial subpopulations allow to study the relationship between these organelles and disease.
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Affiliation(s)
- Nicola Lai
- Department of Electrical and Computer Engineering; Old Dominion University; Norfolk Virginia
- Biomedical Engineering Institute; Old Dominion University; Norfolk Virginia
- Department of Biomedical Engineering; Case Western Reserve University; Cleveland Ohio
| | - China M. Kummitha
- Department of Electrical and Computer Engineering; Old Dominion University; Norfolk Virginia
- Biomedical Engineering Institute; Old Dominion University; Norfolk Virginia
- Department of Biomedical Engineering; Case Western Reserve University; Cleveland Ohio
| | - Mariana G. Rosca
- Department of Foundational Sciences; Central Michigan University College of Medicine; Mount Pleasant Michigan
| | - Hisashi Fujioka
- Center for Mitochondrial Diseases; Case Western Reserve University; Cleveland Ohio
| | - Bernard Tandler
- Department of Biological Sciences; Case Western Reserve University School of Dental Medicine; Cleveland Ohio
| | - Charles L. Hoppel
- Center for Mitochondrial Diseases; Case Western Reserve University; Cleveland Ohio
- Department of Pharmacology; Case Western Reserve University; Cleveland Ohio
- Department of Medicine; School of Medicine; Case Western Reserve University; Cleveland Ohio
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Li JH, Liu XR, Zhang Y, Tian FF, Zhao GY, Yu QLY, Jiang FL, Liu Y. Toxicity of nano zinc oxide to mitochondria. Toxicol Res (Camb) 2012. [DOI: 10.1039/c2tx20016c] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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5
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Feng Y, Lu Y, Lin X, Gao Y, Zhao Q, Li W, Wang R. Endomorphins and morphine limit anoxia-reoxygenation-induced brain mitochondrial dysfunction in the mouse. Life Sci 2008; 82:752-63. [PMID: 18272183 DOI: 10.1016/j.lfs.2008.01.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Revised: 01/15/2008] [Accepted: 01/16/2008] [Indexed: 11/17/2022]
Abstract
The protection of brain mitochondria from oxidative stress is an important therapeutic strategy against ischemia-reperfusion injury and neurodegenerative disorders. Isolated brain mitochondria subjected to a 5 min period of anoxia followed by 5 min reoxygenation mirrored the effect of oxidative stress in the brain. The present study attempts to evaluate the protective effects of endomorphin 1 (EM1), endomorphin 2 (EM2), and morphine (Mor) in an in vitro mouse brain mitochondria anoxia-reoxygenation model. Endomorphins (EM1/2) and Mor were added to mitochondria prior to anoxia or reoxygenation. EM1/2 and Mor markedly improved mitochondrial respiratory activity with a decrease in state 4 and increases in state 3, respiratory control ratio (RCR) and the oxidative phosphorylation efficiency (ADP/O ratio), suggesting that they may play a protective role in mitochondria. These drugs inhibited alterations in mitochondrial membrane fluidity, lipoperoxidation, and cardiolipin (CL) release, which indicates protection of the mitochondrial membranes from oxidative damage. The protective effects of these drugs were concentration-dependent. Furthermore, these drugs blocked the enhanced release of cytochrome c (Cyt c), and consequently inhibited the cell apoptosis induced by the release of Cyt c. Our results suggest that EM1/2 and Mor effectively protect brain mitochondria against oxidative stresses induced by in vitro anoxia-reoxygenation and may play an important role in the prevention of deleterious effects during brain ischemia-reperfusion and neurodegenerative diseases.
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Affiliation(s)
- Yun Feng
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Lanzhou University, 222 Tianshui South Road, Lanzhou, 730000, PR China
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Oktay Y, Dioum E, Matsuzaki S, Ding K, Yan LJ, Haller RG, Szweda LI, Garcia JA. Hypoxia-inducible factor 2alpha regulates expression of the mitochondrial aconitase chaperone protein frataxin. J Biol Chem 2007; 282:11750-6. [PMID: 17322295 DOI: 10.1074/jbc.m611133200] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mice lacking Epas1, encoding the transcription factor Hypoxia-inducible Factor 2alpha (HIF-2alpha), exhibit an apparent mitochondrial disease state. Similarities between knock-outs of Epas1 and of Sod2, encoding the mitochondrial antioxidant enzyme manganese superoxide dismutase, led to the identification of Sod2 as a HIF-2alpha target gene. However, Sod2 levels in Epas1(-)(/)(-) liver are intermediate between that of Sod(+)(/)(-) and Sod2(-)(/)(-) mice, which have subtle or severe phenotypes, respectively. This suggests that additional HIF-2alpha target genes besides Sod2 contribute to the Epas1(-)(/)(-) mitochondrial disease state. To define the nature of the mitochondrial defect in Epas1(-)(/)(-) liver, we performed biophysical, biochemical, and molecular studies. In the setting of decreased Sod2 levels and increased oxidative stress, we found reduced respiration, sensitized mitochondrial permeability transition pore opening, intact electron transport chain activities, and impaired mitochondrial aconitase activity. Mitochondrial aconitase protein levels were preserved, whereas mRNA and protein levels for frataxin, the oxidative stress-regulated mitochondrial aconitase chaperone protein, were markedly reduced in Epas1(-)(/)(-) livers. The mouse Fxn promoter was preferentially activated by HIF-2alpha through a consensus HIF-responsive enhancer element. In summary, the studies reveal that Fxn, like Sod2, is a nuclear-encoded, mitochondrial-localized HIF-2alpha target gene required for optimal mitochondrial homeostasis. These findings expand upon the previously defined role of HIF-2alpha in the cellular response to oxidative stress and identify a novel link of HIF-2alpha with mitochondrial homeostasis.
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Affiliation(s)
- Yavuz Oktay
- Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390, USA
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7
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Nukala VN, Singh IN, Davis LM, Sullivan PG. Cryopreservation of brain mitochondria: a novel methodology for functional studies. J Neurosci Methods 2005; 152:48-54. [PMID: 16246427 DOI: 10.1016/j.jneumeth.2005.08.017] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2005] [Revised: 08/15/2005] [Accepted: 08/17/2005] [Indexed: 11/20/2022]
Abstract
Often, comparative studies involving large number of animals or human post-mortem tissue samples are precluded, especially those requiring structurally and functionally intact cells and/or organelles. The ability to 'bank' such samples for storage and restore or 'reanimate' them at a later time without causing damage to the structure and/or function becomes imperative. However, to date, such attempts have produced conflicting results. We here demonstrate for the first time that isolated rat brain mitochondria can be successfully cryopreserved and restored for later use. We added a well characterized cryoprotectant 10% (v/v) dimethyl sulfoxide (DMSO) to purified rat cortical mitochondria and allowed them to cool at a uniform rate of approximately 1 degree C/min and stored them at -80 degrees C. Freshly isolated as well as reanimated brain mitochondria were analyzed for respiration. Structural integrity of cryopreserved mitochondria was also verified by electron microscopy. Mitochondrial membrane marker levels were assessed along with cytochrome c levels. Intact structure and function of the cryopreserved brain mitochondria observed allows us the opportunity to store mitochondria for longer periods of time as well as perform metabolic studies as needed. This will considerably expand the time-frame required for carrying out functional analysis in large comparative studies.
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Affiliation(s)
- Vidya N Nukala
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, USA
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8
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Safiulina D, Kaasik A, Seppet E, Peet N, Zharkovsky A, Seppet E. Method for in situ detection of the mitochondrial function in neurons. J Neurosci Methods 2004; 137:87-95. [PMID: 15196830 DOI: 10.1016/j.jneumeth.2004.02.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2003] [Revised: 02/10/2004] [Accepted: 02/12/2004] [Indexed: 10/26/2022]
Abstract
Conventional studies of neuronal mitochondria have been limited to the use of purified preparations of isolated mitochondria, neural cell homogenates, living neurons, or brain slices. However, each technique has several drawbacks. Here, we demonstrate that the neuronal cell's membrane can be effectively permeabilized by saponin-treatment and that these permeabilized neurons can be used for qualitative and quantitative assessments of oxygen consumption in combination with registration of mitochondrial membrane potential and free [Ca2+] in the matrix. Under these conditions, the mitochondrial function can be studied without removing the mitochondria from their natural milieu thus avoiding the damage of the associated cytoskeleton and outer membrane. At the same time, the method allows the estimation of the mitochondrial function independently of other processes in the cell, and the easy manipulation of the milieu surrounding the mitochondria. Thus, the presented method offers the opportunity to study the neuronal mitochondrial function in situ and can also be applied to examine the mitochondrial function by other commonly used methods.
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Affiliation(s)
- Dzhamilja Safiulina
- Department of Pharmacology, Faculty of Medicine, Centre of Excellence for Molecular and Clinical Medicine, University of Tartu, Ravila 19, 51014 Tartu, Estonia
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9
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Lerman-Sagie T, Leshinsky-Silver E, Watemberg N, Lev D. Should autistic children be evaluated for mitochondrial disorders? J Child Neurol 2004; 19:379-81. [PMID: 15224710 DOI: 10.1177/088307380401900510] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Autism is etiologically heterogeneous; medical conditions are implicated in only a minority of cases, whereas metabolic disorders are even less common. Recently, there have been articles describing the association of autism with mitochondrial abnormalities. We critically review the current literature and conclude that mitochondrial disorders are probably a rare and insignificant cause of pure autism; however, evidence is accumulating that both autosomal recessive and maternally inherited mitochondrial disorders can present with autistic features. Most patients will present with multisystem abnormalities associated with autistic behavior. Finding biochemical or structural mitochondrial abnormalities in an autistic child does not necessarily imply a primary mitochondrial disorder but can also be secondary to technical inaccuracies or another genetic disorder. Clinicians should be careful in diagnosing a mitochondrial disorder in an autistic child because it has important implications for accurate genetic counseling, prognosis, and therapy.
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Affiliation(s)
- Tally Lerman-Sagie
- Mitochondrial Disease Clinic, Metabolic Neurogenetic Service, Wolfson Medical Center, Holon, Israel.
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10
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Kuznetsov AV, Kunz WS, Saks V, Usson Y, Mazat JP, Letellier T, Gellerich FN, Margreiter R. Cryopreservation of mitochondria and mitochondrial function in cardiac and skeletal muscle fibers. Anal Biochem 2003; 319:296-303. [PMID: 12871725 DOI: 10.1016/s0003-2697(03)00326-9] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Long-term preservation of muscle mitochondria for consequent functional analysis is an important and still unresolved challenge in the clinical study of metabolic diseases and in the basic research of mitochondrial physiology. We here present a method for cryopreservation of mitochondria in various muscle types including human biopsies. Mitochondrial function was analyzed after freeze-thawing permeabilized muscle fibers using glycerol and dimethyl sulfoxide as cryoprotectant. Using optimal freeze-thawing conditions, high rates of adenosine 5(')-diphosphate-stimulated respiration and high respiratory control were observed, showing intactness of mitochondrial respiratory function after cryopreservation. Measurement of adenosine 5(')-triphosphate (ATP) formation showed normal rates of ATP synthesis and ATP/O ratios. Intactness of the outer mitochondrial membrane and functional coupling between mitochondrial creatine kinase and oxidative phosphorylation were verified by respiratory cytochrome c and creatine tests. Simultaneous confocal imaging of mitochondrial flavoproteins and nicotinamide adenine dinucleotide revealed normal intracellular arrangement and metabolic responses of mitochondria after freeze-thawing. The method therefore permits, after freezing and long-term storage of muscle samples, mitochondrial function to be estimated and energy metabolism to be monitored in situ. This will significantly expand the scope for screening and exchange of human biopsy samples between research centers, thus providing a new basis for functional analysis of mitochondrial defects in various diseases.
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Affiliation(s)
- Andrey V Kuznetsov
- Department of Transplant Surgery, University Hospital Innsbruck, Austria.
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11
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Fiskum G, Kowaltowksi AJ, Andreyev AY, Kushnareva YE, Starkov AA. Apoptosis-related activities measured with isolated mitochondria and digitonin-permeabilized cells. Methods Enzymol 2001; 322:222-34. [PMID: 10914020 DOI: 10.1016/s0076-6879(00)22023-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- G Fiskum
- Department of Anesthesiology, University of Maryland, Baltimore 21201, USA
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12
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Grabelnych OI, Pobezhimova TP, Kolesnichenko AV, Voinikov VK. Complex I of winter wheat mitochondria respiratory chain is the most sensitive to uncoupling action of plant stress-related uncoupling protein CSP 310. J Therm Biol 2001; 26:47-53. [PMID: 11070344 DOI: 10.1016/s0306-4565(00)00025-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The influence of stress uncoupling protein CSP 310 on functional stability of different mitochondrial respiratory chain complexes was analysed using various substrates of the tricarboxylic acid cycle. Complex I was the most sensitive to CSP 310 uncoupling action whilst other complexes were more stabile. It is proposed that the key point of CSP 310 uncoupling action is complex I of plant mitochondrial respiratory chain.
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Affiliation(s)
- OI Grabelnych
- Siberian Institute of Plant Physiology and Biochemistry, Siberian Division of Russian Academy of Sciences, PO Box 1243, 664033 33, Irkutsk, Russia
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13
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Marti A, Larrarte E, Novo FJ, Garcia M, Martinez JA. UCP2 muscle gene transfer modifies mitochondrial membrane potential. Int J Obes (Lond) 2001; 25:68-74. [PMID: 11244460 DOI: 10.1038/sj.ijo.0801484] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE The aim of this work was to evaluate the effect of uncoupling protein 2 (UCP2) muscle gene transfer on mitochondrial activity. DESIGN Five week-old male Wistar rats received an intramuscular injection of plasmid pXU1 containing UCP2 cDNA in the right tibialis anterior muscles. Left tibialis anterior muscles were injected with vehicle as control. Ten days after DNA injection, tibialis anterior muscles were dissected and muscle mitochondria isolated and analyzed. RESULTS There were two mitochondrial populations in the muscle after UCP2 gene transfer, one of low fluorescence and complexity and the other, showing high fluorescence and complexity. UCP2 gene transfer resulted in a 3.6 fold increase in muscle UCP2 protein levels compared to control muscles assessed by Western blotting. Furthermore, a significant reduction in mitochondria membrane potential assessed by spectrofluorometry and flow cytometry was observed. The mitochondria membrane potential reduction might account for a decrease in fluorescence of the low fluorescence mitochondrial subpopulation. CONCLUSION It has been demonstrated that UCP2 muscle gene transfer in vivo is associated with a lower mitochondria membrane potential. Our results suggest the potential involvement of UCP2 in uncoupling respiration. International Journal of Obesity (2001) 25, 68-74
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Affiliation(s)
- A Marti
- Department of Physiology and Nutrition, University of Navarra, Pamplona, Spain
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Rasmussen UF, Rasmussen HN. Human quadriceps muscle mitochondria: a functional characterization. Mol Cell Biochem 2000; 208:37-44. [PMID: 10939626 DOI: 10.1023/a:1007046028132] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Human quadriceps mitochondria were isolated from ca. 80 mg tissue in ca. 45% yield. The preparation is described with respect to content of mitochondrial markers and nine different respiratory activities. The specific state 3 activities were high in comparison with literature data, indicating high integrity and purity of the preparation. Examples of state 3 rates, in micromol O min(-1) g protein(-1) (25 degrees C): pyruvate + malate, 400; succinate, 514; malate + glutamate, 444. The notion of high integrity was also supported by the reproducibility of the preparation and the magnitude of the respiratory control ratios and the P/O ratios. The mitochondria most likely had lost ca. 30% of their cytochrome c upon isolation, but it was substantiated that this loss had not influenced the state 3 rates. Functional assays of single reactions or groups of reactions could be based on respiration experiments. The respiratory chain activity, for instance, was measured as respiration of NADH in freeze-permeabilized mitochondria (1263 micromol O min(-1) g protein(-1)). Comparison of uncoupled rates of respiration and state 3 rates indicated that the ATP synthesis exerted major flux control over respiration of succinate + glutamate, malate + glutamate and pyruvate + malate. These reactions, showing very similar rates of ATP synthesis, could be used as a functional assay of ATP synthesis (1200 micromol ATP min(-1) g protein(-1)). Respiration of succinate, palmitoyl-carnitine + malate, or glutamate could not support the maximal rate of ATP synthesis and the upstream reactions probably exerted major flux control in these cases. The specific activities appeared very constant in this group of young men, only the respiratory activity with glutamate might show biological variation.
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Affiliation(s)
- U F Rasmussen
- Department of Biochemistry, August Krogh Institute, University of Copenhagen, Denmark
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Pourzand C, Tyrrell RM. Apoptosis, the Role of Oxidative Stress and the Example of Solar UV Radiation. Photochem Photobiol 1999. [DOI: 10.1111/j.1751-1097.1999.tb08239.x] [Citation(s) in RCA: 115] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Kavanagh KY, Murphy EJ, Harmey M, Farrell MA, Hardimann O, Perryman R, Walsh JE. Microspectrophotometric analysis of respiratory pigments using a novel fibre optic dip probe in microsamples. Physiol Meas 1999; 20:303-11. [PMID: 10475583 DOI: 10.1088/0967-3334/20/3/307] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A microspectrophotometer system to monitor the reduction of mitochondrial respiratory pigments in cell extracts and permeabilized cells has been developed. The novel optical fibre set-up uses visible spectrophotometry to measure the reduction of mitochondrial electron carriers. The basis of the system is an Ocean Optics S1000 spectrometer, a broadband tungsten based light source, input and output coupling fibre optics and a fibre optic dip-probe which requires less than 20 microl of sample for analysis. The spectral range of the system is from 250 to 850 nm with a spectral resolution of 0.5 nm. Data are presented for the reduction of purified cytochrome c by the reducing agent sodium dithionite and the reduction of cytochrome c by isolated mitochondria using sodium succinate as substrate. Reduction of cytochrome c by digitonin permeabilized cultured mouse cells, C2C12, is also shown. The effect of temperature on cytochrome c reduction in these assays is also demonstrated. The optical design of the probe system is optimized to maintain maximum light throughput and spectral resolution. The key features of the system are small sample size, front-end adaptability, high sensitivity and fast multispectral acquisition which are essential for observing these biological reactions in vivo.
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Affiliation(s)
- K Y Kavanagh
- Optical Sensors and Metrology Laboratory, School of Physics, Dublin Institute of Technology, Ireland.
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Fujimura M, Morita-Fujimura Y, Murakami K, Kawase M, Chan PH. Cytosolic redistribution of cytochrome c after transient focal cerebral ischemia in rats. J Cereb Blood Flow Metab 1998; 18:1239-47. [PMID: 9809513 DOI: 10.1097/00004647-199811000-00010] [Citation(s) in RCA: 245] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Recent in vitro cell-free studies have shown that cytochrome c release from mitochondria is a critical step in the apoptotic process. The present study examined the expression of cytochrome c protein after transient focal cerebral ischemia in rats, in which apoptosis was assumed to contribute to the expansion of the ischemic lesion. In situ labeling of DNA breaks in frozen sections after 90 minutes of middle cerebral artery (MCA) occlusion showed a significant number of striatal and cortical neurons, which were maximized at 24 hours after ischemia, exhibiting chromatin condensation, nuclear segmentation, and apoptotic bodies. Cytosolic localization of cytochrome c was detected immunohistochemically in the ischemic area as early as 4 hours after 90 minutes of MCA occlusion. Western blot analysis of the cytosolic fraction revealed a strong single 15-kDa band, characteristic of cytochrome c, only in the samples from the ischemic hemisphere. Western blot analysis of the mitochondrial fraction showed a significant amount of mitochondrial cytochrome c in nonischemic brain, which was decreased in ischemic brain 24 hours after ischemia. These results provide the first evidence that cytochrome c is being released from mitochondria to the cytosol after transient focal ischemia. Although further evaluation is necessary to elucidate its correlation with DNA fragmentation, our results suggest the possibility that cytochrome c release may play a role in DNA-damaged neuronal cell death after transient focal cerebral ischemia in rats.
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Affiliation(s)
- M Fujimura
- Department of Neurosurgery, Stanford University School of Medicine, Palo Alto, California 94304, USA
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Ernster L. Wanderings in bioenergetics with Licio Azzone. Biofactors 1998; 8:173-5, iii. [PMID: 9914815 DOI: 10.1002/biof.5520080302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- L Ernster
- Department of Biochemistry, Arrhenius Laboratories for Natural Sciences, Stockholm University, Sweden
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Affiliation(s)
- C P Lee
- Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, MI 48201, USA
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