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Ohanele C, Peoples JN, Karlstaedt A, Geiger JT, Gayle AD, Ghazal N, Sohani F, Brown ME, Davis ME, Porter GA, Faundez V, Kwong JQ. Mitochondrial citrate carrier SLC25A1 is a dosage-dependent regulator of metabolic reprogramming and morphogenesis in the developing heart. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.05.22.541833. [PMID: 37292906 PMCID: PMC10245819 DOI: 10.1101/2023.05.22.541833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The developing mammalian heart undergoes an important metabolic shift from glycolysis toward mitochondrial oxidation, such that oxidative phosphorylation defects may present with cardiac abnormalities. Here, we describe a new mechanistic link between mitochondria and cardiac morphogenesis, uncovered by studying mice with systemic loss of the mitochondrial citrate carrier SLC25A1. Slc25a1 null embryos displayed impaired growth, cardiac malformations, and aberrant mitochondrial function. Importantly, Slc25a1 heterozygous embryos, which are overtly indistinguishable from wild type, exhibited an increased frequency of these defects, suggesting Slc25a1 haploinsuffiency and dose-dependent effects. Supporting clinical relevance, we found a near-significant association between ultrarare human pathogenic SLC25A1 variants and pediatric congenital heart disease. Mechanistically, SLC25A1 may link mitochondria to transcriptional regulation of metabolism through epigenetic control of gene expression to promote metabolic remodeling in the developing heart. Collectively, this work positions SLC25A1 as a novel mitochondrial regulator of ventricular morphogenesis and cardiac metabolic maturation and suggests a role in congenital heart disease.
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2
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Guo J, Chen X, Liu Z, Sun H, Zhou Y, Dai Y, Ma Y, He L, Qian X, Wang J, Zhang J, Zhu Y, Zhang J, Shen B, Zhou F. DdCBE mediates efficient and inheritable modifications in mouse mitochondrial genome. MOLECULAR THERAPY. NUCLEIC ACIDS 2022; 27:73-80. [PMID: 34938607 PMCID: PMC8646052 DOI: 10.1016/j.omtn.2021.11.016] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 11/16/2021] [Indexed: 11/30/2022]
Abstract
Critical mutations of mitochondrial DNA (mtDNA) generally lead to maternally inheritable diseases that affect multiple organs and systems; however, it was difficult to alter mtDNA in mammalian cells to intervene in or cure mitochondrial disorders. Recently, the discovery of DddA-derived cytosine base editor (DdCBE) enabled the precise manipulation of mtDNA. To test its feasibility for in vivo use, we selected several sites in mouse mtDNA as DdCBE targets to resemble the human pathogenic mtDNA G-to-A mutations. The efficiency of DdCBE-mediated mtDNA editing was first screened in mouse Neuro-2A cells and DdCBE pairs with the best performance were chosen for in vivo targeting. Microinjection of the mRNAs of DdCBE halves in the mouse zygotes or 2-cell embryo successfully generated edited founder mice with a base conversion rate ranging from 2.48% to 28.51%. When backcrossed with wild-type male mice, female founders were able to transmit the mutations to their offspring with different mutation loads. Off-target analyses demonstrated a high fidelity for DdCBE-mediated base editing in mouse mtDNA both in vitro and in vivo. Our study demonstrated that the DdCBE is feasible for generation of mtDNA mutation models to facilitate disease study and for potential treatment of mitochondrial disorders.
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Affiliation(s)
- Jiayin Guo
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China
- Gusu School, Nanjing Medical University, Nanjing 211166, China
| | - Xiaoxu Chen
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China
| | - Zhiwei Liu
- Cambridge-Suda Genomic Resource Center, Jiangsu Key Laboratory of Neuropsychiatric Diseases Research, Medical College of Soochow University, Suzhou 215123, China
| | - Haifeng Sun
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China
| | - Yu Zhou
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China
| | - Yichen Dai
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China
| | - Yu'e Ma
- Cambridge-Suda Genomic Resource Center, Jiangsu Key Laboratory of Neuropsychiatric Diseases Research, Medical College of Soochow University, Suzhou 215123, China
| | - Lei He
- Cambridge-Suda Genomic Resource Center, Jiangsu Key Laboratory of Neuropsychiatric Diseases Research, Medical College of Soochow University, Suzhou 215123, China
| | - Xuezhen Qian
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China
| | - Jianying Wang
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China
| | - Jie Zhang
- Cambridge-Suda Genomic Resource Center, Jiangsu Key Laboratory of Neuropsychiatric Diseases Research, Medical College of Soochow University, Suzhou 215123, China
| | - Yichen Zhu
- Cambridge-Suda Genomic Resource Center, Jiangsu Key Laboratory of Neuropsychiatric Diseases Research, Medical College of Soochow University, Suzhou 215123, China
| | - Jun Zhang
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China
| | - Bin Shen
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China
- Gusu School, Nanjing Medical University, Nanjing 211166, China
- Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing 211166, China
- Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing Medical University, Nanjing 211166, China
| | - Fei Zhou
- Cambridge-Suda Genomic Resource Center, Jiangsu Key Laboratory of Neuropsychiatric Diseases Research, Medical College of Soochow University, Suzhou 215123, China
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3
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The Mitochondrial Genome in Aging and Disease and the Future of Mitochondrial Therapeutics. Biomedicines 2022; 10:biomedicines10020490. [PMID: 35203698 PMCID: PMC8962324 DOI: 10.3390/biomedicines10020490] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 02/10/2022] [Accepted: 02/16/2022] [Indexed: 11/29/2022] Open
Abstract
Mitochondria are intracellular organelles that utilize nutrients to generate energy in the form of ATP by oxidative phosphorylation. Mitochondrial DNA (mtDNA) in humans is a 16,569 base pair double-stranded circular DNA that encodes for 13 vital proteins of the electron transport chain. Our understanding of the mitochondrial genome’s transcription, translation, and maintenance is still emerging, and human pathologies caused by mtDNA dysfunction are widely observed. Additionally, a correlation between declining mitochondrial DNA quality and copy number with organelle dysfunction in aging is well-documented in the literature. Despite tremendous advancements in nuclear gene-editing technologies and their value in translational avenues, our ability to edit mitochondrial DNA is still limited. In this review, we discuss the current therapeutic landscape in addressing the various pathologies that result from mtDNA mutations. We further evaluate existing gene therapy efforts, particularly allotopic expression and its potential to become an indispensable tool for restoring mitochondrial health in disease and aging.
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4
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Liang T, Deng J, Nayak B, Zou X, Ikeno Y, Bai Y. Characterizing the Electron Transport Chain: Structural Approach. Methods Mol Biol 2022; 2497:107-115. [PMID: 35771438 DOI: 10.1007/978-1-0716-2309-1_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The mitochondrial respiratory chain which carries out the oxidative phosphorylation (OXPHOS) consists of five multi-subunit protein complexes. Emerging evidences suggest that the supercomplexes which further consist of multiple respiratory complexes play important role in regulating OXPHOS function. Dysfunction of the respiratory chain and its regulation has been implicated in various human diseases including neurodegenerative diseases and muscular disorders. Many mouse models have been established which exhibit mitochondrial defects in brain and muscles. Protocols presented here aim to help to analyze the structures of mitochondrial respiratory chain which include the preparation of the tissue samples, isolation of mitochondrial membrane proteins, and analysis of their respiratory complexes by Blue Native Polyacrylamide Gel Electrophoresis (BN-PAGE) in particular.
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Affiliation(s)
- Ting Liang
- Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China
- Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Janice Deng
- Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Bijaya Nayak
- Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Xin Zou
- Department of Pulmonary and Critical Care Medicine, Longyuan First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian, China
| | - Yuji Ikeno
- Department of Pathology, Barshop Institute of Longevity and Aging Research, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Yidong Bai
- Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, TX, USA.
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5
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Vidali S, Gerlini R, Thompson K, Urquhart JE, Meisterknecht J, Aguilar‐Pimentel JA, Amarie OV, Becker L, Breen C, Calzada‐Wack J, Chhabra NF, Cho Y, da Silva‐Buttkus P, Feichtinger RG, Gampe K, Garrett L, Hoefig KP, Hölter SM, Jameson E, Klein‐Rodewald T, Leuchtenberger S, Marschall S, Mayer‐Kuckuk P, Miller G, Oestereicher MA, Pfannes K, Rathkolb B, Rozman J, Sanders C, Spielmann N, Stoeger C, Szibor M, Treise I, Walter JH, Wurst W, Mayr JA, Fuchs H, Gärtner U, Wittig I, Taylor RW, Newman WG, Prokisch H, Gailus‐Durner V, Hrabě de Angelis M. Characterising a homozygous two-exon deletion in UQCRH: comparing human and mouse phenotypes. EMBO Mol Med 2021; 13:e14397. [PMID: 34750991 PMCID: PMC8649870 DOI: 10.15252/emmm.202114397] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 10/06/2021] [Accepted: 10/07/2021] [Indexed: 12/27/2022] Open
Abstract
Mitochondrial disorders are clinically and genetically diverse, with isolated complex III (CIII) deficiency being relatively rare. Here, we describe two affected cousins, presenting with recurrent episodes of severe lactic acidosis, hyperammonaemia, hypoglycaemia and encephalopathy. Genetic investigations in both cases identified a homozygous deletion of exons 2 and 3 of UQCRH, which encodes a structural complex III (CIII) subunit. We generated a mouse model with the equivalent homozygous Uqcrh deletion (Uqcrh-/- ), which also presented with lactic acidosis and hyperammonaemia, but had a more severe, non-episodic phenotype, resulting in failure to thrive and early death. The biochemical phenotypes observed in patient and Uqcrh-/- mouse tissues were remarkably similar, displaying impaired CIII activity, decreased molecular weight of fully assembled holoenzyme and an increase of an unexpected large supercomplex (SXL ), comprising mostly of one complex I (CI) dimer and one CIII dimer. This phenotypic similarity along with lentiviral rescue experiments in patient fibroblasts verifies the pathogenicity of the shared genetic defect, demonstrating that the Uqcrh-/- mouse is a valuable model for future studies of human CIII deficiency.
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Rubenstein DR, Corvelo A, MacManes MD, Maia R, Narzisi G, Rousaki A, Vandenabeele P, Shawkey MD, Solomon J. Feather Gene Expression Elucidates the Developmental Basis of Plumage Iridescence in African Starlings. J Hered 2021; 112:417-429. [PMID: 33885791 DOI: 10.1093/jhered/esab014] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 03/19/2021] [Indexed: 01/08/2023] Open
Abstract
Iridescence is widespread in the living world, occurring in organisms as diverse as bacteria, plants, and animals. Yet, compared to pigment-based forms of coloration, we know surprisingly little about the developmental and molecular bases of the structural colors that give rise to iridescence. Birds display a rich diversity of iridescent structural colors that are produced in feathers by the arrangement of melanin-containing organelles called melanosomes into nanoscale configurations, but how these often unusually shaped melanosomes form, or how they are arranged into highly organized nanostructures, remains largely unknown. Here, we use functional genomics to explore the developmental basis of iridescent plumage using superb starlings (Lamprotornis superbus), which produce both iridescent blue and non-iridescent red feathers. Through morphological and chemical analyses, we confirm that hollow, flattened melanosomes in iridescent feathers are eumelanin-based, whereas melanosomes in non-iridescent feathers are solid and amorphous, suggesting that high pheomelanin content underlies red coloration. Intriguingly, the nanoscale arrangement of melanosomes within the barbules was surprisingly similar between feather types. After creating a new genome assembly, we use transcriptomics to show that non-iridescent feather development is associated with genes related to pigmentation, metabolism, and mitochondrial function, suggesting non-iridescent feathers are more energetically expensive to produce than iridescent feathers. However, iridescent feather development is associated with genes related to structural and cellular organization, suggesting that, while nanostructures themselves may passively assemble, barbules and melanosomes may require active organization to give them their shape. Together, our analyses suggest that iridescent feathers form through a combination of passive self-assembly and active processes.
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Affiliation(s)
- Dustin R Rubenstein
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY
- Center for Integrative Animal Behavior, Columbia University, New York, NY
| | | | - Matthew D MacManes
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH
| | - Rafael Maia
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY
| | | | - Anastasia Rousaki
- Raman Spectroscopy Research Group, Department of Chemistry, Ghent University, Krigslaan, Ghent, Belgium
| | - Peter Vandenabeele
- Raman Spectroscopy Research Group, Department of Chemistry, Ghent University, Krigslaan, Ghent, Belgium
- Archaeometry Research Group, Department of Archaeology, Ghent University, Sint-Pietersnieuwstraat, Ghent, Belgium
| | - Matthew D Shawkey
- Evolution and Optics of Nanostructures Group, Department of Biology, Ghent University, Ghent, Belgium
| | - Joseph Solomon
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY
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7
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Bakare AB, Lesnefsky EJ, Iyer S. Leigh Syndrome: A Tale of Two Genomes. Front Physiol 2021; 12:693734. [PMID: 34456746 PMCID: PMC8385445 DOI: 10.3389/fphys.2021.693734] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 07/22/2021] [Indexed: 12/21/2022] Open
Abstract
Leigh syndrome is a rare, complex, and incurable early onset (typically infant or early childhood) mitochondrial disorder with both phenotypic and genetic heterogeneity. The heterogeneous nature of this disorder, based in part on the complexity of mitochondrial genetics, and the significant interactions between the nuclear and mitochondrial genomes has made it particularly challenging to research and develop therapies. This review article discusses some of the advances that have been made in the field to date. While the prognosis is poor with no current substantial treatment options, multiple studies are underway to understand the etiology, pathogenesis, and pathophysiology of Leigh syndrome. With advances in available research tools leading to a better understanding of the mitochondria in health and disease, there is hope for novel treatment options in the future.
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Affiliation(s)
- Ajibola B. Bakare
- Department of Biological Sciences, J. William Fulbright College of Arts and Sciences, University of Arkansas, Fayetteville, AR, United States
| | - Edward J. Lesnefsky
- Division of Cardiology, Pauley Heart Center, Department of Internal Medicine, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States
- Department of Physiology/Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States
- Department of Biochemistry and Molecular Biology, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States
| | - Shilpa Iyer
- Department of Biological Sciences, J. William Fulbright College of Arts and Sciences, University of Arkansas, Fayetteville, AR, United States
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8
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Stewart JB. Current progress with mammalian models of mitochondrial DNA disease. J Inherit Metab Dis 2021; 44:325-342. [PMID: 33099782 DOI: 10.1002/jimd.12324] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 10/19/2020] [Accepted: 10/21/2020] [Indexed: 12/16/2022]
Abstract
Mitochondrial disorders make up a large class of heritable diseases that cause a broad array of different human pathologies. They can affect many different organ systems, or display very specific tissue presentation, and can lead to illness either in childhood or later in life. While the over 1200 genes encoded in the nuclear DNA play an important role in human mitochondrial disease, it has been known for over 30 years that mutations of the mitochondria's own small, multicopy DNA chromosome (mtDNA) can lead to heritable human diseases. Unfortunately, animal mtDNA has resisted transgenic and directed genome editing technologies until quite recently. As such, animal models to aid in our understanding of these diseases, and to explore preclinical therapeutic research have been quite rare. This review will discuss the unusual properties of animal mitochondria that have hindered the generation of animal models. It will also discuss the existing mammalian models of human mtDNA disease, describe the methods employed in their generation, and will discuss recent advances in the targeting of DNA-manipulating enzymes to the mitochondria and how these may be employed to generate new models.
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Affiliation(s)
- James Bruce Stewart
- Max Planck Institute for Biology of Ageing, Cologne, Germany
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
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9
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Ma Y, Zhu S, Lv T, Gu X, Feng H, Zhen J, Xin W, Wan Q. SQSTM1/p62 Controls mtDNA Expression and Participates in Mitochondrial Energetic Adaption via MRPL12. iScience 2020; 23:101428. [PMID: 32805647 PMCID: PMC7452302 DOI: 10.1016/j.isci.2020.101428] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 06/19/2020] [Accepted: 07/30/2020] [Indexed: 02/07/2023] Open
Abstract
Mitochondrial DNA (mtDNA) encodes thirteen core components of OXPHOS complexes, and its steady expression is crucial for cellular energy homeostasis. However, the regulation of mtDNA expression machinery, along with its sensing mechanism to energetic stresses, is not fully understood. Here, we identified SQSTM1/p62 as an important regulator of mtDNA expression machinery, which could effectively induce mtDNA expression and the effects were mediated by p38-dependent upregulation of mitochondrial ribosomal protein L12 (MRPL12) in renal tubular epithelial cells (TECs), a highly energy-demanding cell type related to OXPHOS. We further identified a direct binding site within the MRPL12 promoter to ATF2, the downstream effector of p38. Besides, SQSTM1/p62-induced mtDNA expression is involved in both serum deprivation and hypoxia-induced mitochondrial response, which was further highlighted by kidney injury phenotype of TECs-specific SQSTM1/p62 knockout mice. Collectively, these data suggest that SQSTM1/p62 is a key regulator and energetic sensor of mtDNA expression machinery. SQSTM1/p62 is an important regulator of mtDNA expression machinery SQSTM1/p62 induces MRPL12 expression via activating p38/ATF2 signaling pathway SQSTM1/p62 maintains TECs mitochondrial homeostasis and kidney function
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Affiliation(s)
- Yuan Ma
- Renal Division, Peking University First Hospital, Peking University Institute of Nephrology, Beijing 100034, China
| | - Suwei Zhu
- School of Medicine, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
| | - Tingting Lv
- School of Medicine, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
| | - Xia Gu
- School of Medicine, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
| | - Hong Feng
- Cancer Center, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan 250012, China
| | - Junhui Zhen
- Department of Pathology, School of Medicine, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
| | - Wei Xin
- Department of Central Laboratory, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan 250012, China; Department of Central Laboratory, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan 250012, China.
| | - Qiang Wan
- Department of Endocrinology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan 250012, China.
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10
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Truong L, Zheng YM, Wang YX. Mitochondrial Rieske iron-sulfur protein in pulmonary artery smooth muscle: A key primary signaling molecule in pulmonary hypertension. Arch Biochem Biophys 2020; 683:108234. [PMID: 31980131 DOI: 10.1016/j.abb.2019.108234] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Rieske iron-sulfur protein (RISP) is a catalytic subunit of the complex III in the mitochondrial electron transport chain. Studies for years have revealed that RISP is essential for the generation of intracellular reactive oxygen species (ROS) via delicate signaling pathways associated with many important molecules such as protein kinase C-ε, NADPH oxidase, and ryanodine receptors. More significantly, mitochondrial RISP-mediated ROS production has been implicated in the development of hypoxic pulmonary vasoconstriction, leading to pulmonary hypertension, right heart failure, and death. Investigations have also shown the involvement of RISP in ROS-dependent cardiac ischemic/reperfusion injuries. Further research may provide novel and valuable information that can not only enhance our understanding of the functional roles of RISP and the underlying molecular mechanisms in the pulmonary vasculature and other systems, but also elucidate whether RISP targeting can act as preventative and restorative therapies against pulmonary hypertension, cardiac diseases, and other disorders.
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Affiliation(s)
- Lillian Truong
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, 12208, USA
| | - Yun-Min Zheng
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, 12208, USA
| | - Yong-Xiao Wang
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, 12208, USA.
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11
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Zi J, Wang W, Sun M, Mei W, Li S, Li B, Xiao Y, Fei Z, Zhang R, Yu M, Xiong W. A high expression of MTERF3 correlates with tumor progression and predicts poor outcomes in patients with brain glioma. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2019; 12:1909-1920. [PMID: 31934014 PMCID: PMC6947131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Accepted: 04/18/2019] [Indexed: 06/10/2023]
Abstract
Mitochondrial transcription termination factor 3 (MTERF3) is a negative regulator of mitochondrial transcription. MTERF3 is overexpressed in liver cancer, pancreatic cancer, lung cancer, and breast cancer. However, whether MTERF3 is up-regulated in brain glioma is still unclear. The aim of this study was to investigate the expression and clinicopathological significance of MTERF3 in brain glioma and to analyze its potential prognostic value in brain glioma. Immunohistochemistry, Western blot, and a semi-quantitative RT-PCR were performed to analyze the protein and mRNA expression levels of MTERF3 in 28 human brain glioma tissues and 10 noncancerous brain tissues. The expression data of MTERF3 and its clinical information in brain glioma were downloaded from the TCGA dataset using R 2.15.3 software. The relationship between the expression of MTERF3 and its clinicopathological characteristics and its prognostic value was analyzed. A Cox regression model was used for a multivariate analysis of the factors affecting the prognosis of brain glioma. The immunohistochemistry results showed that the MTERF3 protein is located in the cytoplasm, and the positive expression rate of the MTERF3 protein in brain glioma tissues is 64.29%. We found that the positive expression rate of the MTERF3 protein in high-grade glioma tissues (81.25%) is higher than it is in low-grade glioma tissues (41.67%). The expression levels of the MTERF3 mRNA and protein in brain glioma tissues are significantly higher than they are in the noncancerous brain tissues. Moreover, the expression of MTERF3 is significantly correlated with age, tumor type, and pathological classification (P<0.05). A Kaplan-Meier analysis showed that a high expression level of MTERF3 mRNA indicated a poor prognosis (log rank P<0.01). Furthermore, a multivariate Cox regression analysis showed that age and tumor type were independent prognostic factors for brain glioma patients. A GEPIA analysis suggested that the expression levels of MTERF3 are positively correlated with the TFAM, TFB1M, TFB2M, MTERF1, MTERF2, TEFM, and MFN1 genes, but negatively correlated with the PINK1 gene. The expression level of MTERF3 had no correlation with the MTERF4 gene. In conclusion, these data indicate that the expression of MTERF3 in glioma tissue samples can be used as a prognostic factor for patients with glioma and that a high MTERF3 expression correlates with a poor prognosis in glioma patients.
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Affiliation(s)
- Jiaji Zi
- College of Basic Medical Sciences, Dali UniversityDali, Yunnan Province, China
| | - Weisi Wang
- College of Basic Medical Sciences, Dali UniversityDali, Yunnan Province, China
| | - Meitao Sun
- College of Basic Medical Sciences, Dali UniversityDali, Yunnan Province, China
- Department of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical CollegeHangzhou Province, China
| | - Wen Mei
- College of Basic Medical Sciences, Dali UniversityDali, Yunnan Province, China
| | - Sufen Li
- College of Basic Medical Sciences, Dali UniversityDali, Yunnan Province, China
| | - Bin Li
- College of Basic Medical Sciences, Dali UniversityDali, Yunnan Province, China
| | - Yang Xiao
- College of Basic Medical Sciences, Dali UniversityDali, Yunnan Province, China
| | - Zaiyi Fei
- School of Life Sciences, Yunnan UniversityKunming, Yunnan Province, China
| | - Ruopeng Zhang
- Department of Reproductive Medicine, The First Affiliated Hospital of Dali UniversityDali, Yunnan Province, China
| | - Min Yu
- School of Life Sciences, Yunnan UniversityKunming, Yunnan Province, China
| | - Wei Xiong
- College of Basic Medical Sciences, Dali UniversityDali, Yunnan Province, China
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12
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Truong L, Zheng YM, Wang YX. Mitochondrial Rieske iron-sulfur protein in pulmonary artery smooth muscle: A key primary signaling molecule in pulmonary hypertension. Arch Biochem Biophys 2019; 664:68-75. [PMID: 30710505 DOI: 10.1016/j.abb.2019.01.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 01/14/2019] [Accepted: 01/26/2019] [Indexed: 12/17/2022]
Abstract
Rieske iron-sulfur protein (RISP) is a catalytic subunit of the complex III in the mitochondrial electron transport chain. Studies for years have revealed that RISP is essential for the generation of intracellular reactive oxygen species (ROS) via delicate signaling pathways associated with many important molecules such as protein kinase C-ε, NADPH oxidase, and ryanodine receptors. More significantly, mitochondrial RISP-mediated ROS production has been implicated in the development of hypoxic pulmonary vasoconstriction, leading to pulmonary hypertension, right heart failure, and death. Investigations have also shown the involvement of RISP in ROS-dependent cardiac ischemic/reperfusion injuries. Further research may provide novel and valuable information that can not only enhance our understanding of the functional roles of RISP and the underlying molecular mechanisms in the pulmonary vasculature and other systems, but also elucidate whether RISP targeting can act as preventative and restorative therapies against pulmonary hypertension, cardiac diseases, and other disorders.
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Affiliation(s)
- Lillian Truong
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, 12208, USA
| | - Yun-Min Zheng
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, 12208, USA
| | - Yong-Xiao Wang
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, 12208, USA.
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Kuszak AJ, Espey MG, Falk MJ, Holmbeck MA, Manfredi G, Shadel GS, Vernon HJ, Zolkipli-Cunningham Z. Nutritional Interventions for Mitochondrial OXPHOS Deficiencies: Mechanisms and Model Systems. ANNUAL REVIEW OF PATHOLOGY 2018; 13:163-191. [PMID: 29099651 PMCID: PMC5911915 DOI: 10.1146/annurev-pathol-020117-043644] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Multisystem metabolic disorders caused by defects in oxidative phosphorylation (OXPHOS) are severe, often lethal, conditions. Inborn errors of OXPHOS function are termed primary mitochondrial disorders (PMDs), and the use of nutritional interventions is routine in their supportive management. However, detailed mechanistic understanding and evidence for efficacy and safety of these interventions are limited. Preclinical cellular and animal model systems are important tools to investigate PMD metabolic mechanisms and therapeutic strategies. This review assesses the mechanistic rationale and experimental evidence for nutritional interventions commonly used in PMDs, including micronutrients, metabolic agents, signaling modifiers, and dietary regulation, while highlighting important knowledge gaps and impediments for randomized controlled trials. Cellular and animal model systems that recapitulate mutations and clinical manifestations of specific PMDs are evaluated for their potential in determining pathological mechanisms, elucidating therapeutic health outcomes, and investigating the value of nutritional interventions for mitochondrial disease conditions.
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Affiliation(s)
- Adam J Kuszak
- Office of Dietary Supplements, National Institutes of Health, Bethesda, Maryland 20852, USA;
| | - Michael Graham Espey
- Division of Cancer Biology, National Cancer Institute, Rockville, Maryland 20850, USA;
| | - Marni J Falk
- Department of Pediatrics, Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA;
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Marissa A Holmbeck
- Department of Pathology, Yale School of Medicine, New Haven, Connecticut 06510-8023, USA;
| | - Giovanni Manfredi
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA;
| | - Gerald S Shadel
- Department of Pathology, Yale School of Medicine, New Haven, Connecticut 06510-8023, USA;
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut 06520-8023, USA;
| | - Hilary J Vernon
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA;
| | - Zarazuela Zolkipli-Cunningham
- Department of Pediatrics, Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA;
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Hekimi S, Wang Y, Noë A. Mitochondrial ROS and the Effectors of the Intrinsic Apoptotic Pathway in Aging Cells: The Discerning Killers! Front Genet 2016; 7:161. [PMID: 27683586 PMCID: PMC5021979 DOI: 10.3389/fgene.2016.00161] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 08/30/2016] [Indexed: 01/06/2023] Open
Abstract
It has become clear that mitochondrial reactive oxygen species (mtROS) are not simply villains and mitochondria the hapless targets of their attacks. Rather, it appears that mitochondrial dysfunction itself and the signaling function of mtROS can have positive effects on lifespan, helping to extend longevity. If events in the mitochondria can lead to better cellular homeostasis and better survival of the organism in ways beyond providing ATP and biosynthetic products, we can conjecture that they act on other cellular components through appropriate signaling pathways. We describe recent advances in a variety of species which promoted our understanding of how changes of mtROS generation are part of a system of signaling pathways that emanate from the mitochondria to impact organism lifespan through global changes, including in transcriptional patterns. In unraveling this, many old players in cellular homeostasis were encountered. Among these, maybe most strikingly, is the intrinsic apoptotic signaling pathway, which is the conduit by which at least one class of mtROS exercise their actions in the nematode Caenorhabditis elegans. This is a pathway that normally contributes to organismal homeostasis by killing defective or otherwise unwanted cells, and whose various compounds have also been implicated in other cellular processes. However, it was a surprise that that appropriate activation of a cell killing pathway can in fact prolong the lifespan of the organism. In the soma of adult C. elegans, all cells are post-mitotic, like many of our neurons and possibly some of our immune cells. These cells cannot simply be killed and replaced when showing signs of dysfunction. Thus, we speculate that it is the ability of the apoptotic pathway to pull together information about the functional and structural integrity of different cellular compartments that is the key property for why this pathway is used to decide when to boost defensive and repair processes in irreplaceable cells. When this process is artificially stimulated in mutants with elevated mtROS generation or with drug treatments it leads to lifespan prolongations beyond the normal lifespan of the organism.
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Affiliation(s)
| | - Ying Wang
- Department of Biology, McGill University Montreal, QC, Canada
| | - Alycia Noë
- Department of Biology, McGill University Montreal, QC, Canada
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15
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Torraco A, Peralta S, Iommarini L, Diaz F. Mitochondrial Diseases Part I: mouse models of OXPHOS deficiencies caused by defects in respiratory complex subunits or assembly factors. Mitochondrion 2015; 21:76-91. [PMID: 25660179 DOI: 10.1016/j.mito.2015.01.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 11/22/2014] [Accepted: 01/05/2015] [Indexed: 10/24/2022]
Abstract
Mitochondrial disorders are the most common inborn errors of metabolism affecting the oxidative phosphorylation system (OXPHOS). Because of the poor knowledge of the pathogenic mechanisms, a cure for these disorders is still unavailable and all the treatments currently in use are supportive more than curative. Therefore, in the past decade a great variety of mouse models have been developed to assess the in vivo function of several mitochondrial proteins involved in human diseases. Due to the genetic and physiological similarity to humans, mice represent reliable models to study the pathogenic mechanisms of mitochondrial disorders and are precious to test new therapeutic approaches. Here we summarize the features of several mouse models of mitochondrial diseases directly related to defects in subunits of the OXPHOS complexes or in assembly factors. We discuss how these models recapitulate many human conditions and how they have contributed to the understanding of mitochondrial function in health and disease.
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Affiliation(s)
- Alessandra Torraco
- Unit for Neuromuscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital, IRCCS, Viale di San Paolo, 15-00146 Rome, Italy.
| | - Susana Peralta
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
| | - Luisa Iommarini
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Via Irnerio 42, 40126 Bologna, Italy.
| | - Francisca Diaz
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
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16
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Ismailoglu I, Chen Q, Popowski M, Yang L, Gross SS, Brivanlou AH. Huntingtin protein is essential for mitochondrial metabolism, bioenergetics and structure in murine embryonic stem cells. Dev Biol 2014; 391:230-40. [PMID: 24780625 DOI: 10.1016/j.ydbio.2014.04.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 03/20/2014] [Accepted: 04/06/2014] [Indexed: 12/15/2022]
Abstract
Mutations in the Huntington locus (htt) have devastating consequences. Gain-of-poly-Q repeats in Htt protein causes Huntington's disease (HD), while htt(-/-) mutants display early embryonic lethality. Despite its importance, the function of Htt remains elusive. To address this, we compared more than 3700 compounds in three syngeneic mouse embryonic stem cell (mESC) lines: htt(-/-), extended poly-Q (Htt-Q140/7), and wild-type mESCs (Htt-Q7/7) using untargeted metabolite profiling. While Htt-Q140/7 cells did not show major differences in cellular bioenergetics, we find extensive metabolic aberrations in htt(-/-) mESCs, including (i) complete failure of ATP production despite preservation of the mitochondrial membrane potential; (ii) near-maximal glycolysis, with little or no glycolytic reserve; (iii) marked ketogenesis; (iv) depletion of intracellular NTPs; (v) accelerated purine biosynthesis and salvage; and (vi) loss of mitochondrial structural integrity. Together, our findings reveal that Htt is necessary for mitochondrial structure and function from the earliest stages of embryogenesis, providing a molecular explanation for htt(-/-) early embryonic lethality.
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Affiliation(s)
- Ismail Ismailoglu
- Laboratory of Molecular Embryology, The Rockefeller University, New York, NY 10065, USA
| | - Qiuying Chen
- Department of Pharmacology, Weill Cornell College of Medicine, 1300 York Avenue, New York, NY 10065, USA
| | - Melissa Popowski
- Laboratory of Molecular Embryology, The Rockefeller University, New York, NY 10065, USA
| | - Lili Yang
- Department of Pharmacology, Weill Cornell College of Medicine, 1300 York Avenue, New York, NY 10065, USA
| | - Steven S Gross
- Department of Pharmacology, Weill Cornell College of Medicine, 1300 York Avenue, New York, NY 10065, USA.
| | - Ali H Brivanlou
- Laboratory of Molecular Embryology, The Rockefeller University, New York, NY 10065, USA.
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17
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De Rocco D, Cerqua C, Goffrini P, Russo G, Pastore A, Meloni F, Nicchia E, Moraes CT, Pecci A, Salviati L, Savoia A. Mutations of cytochrome c identified in patients with thrombocytopenia THC4 affect both apoptosis and cellular bioenergetics. Biochim Biophys Acta Mol Basis Dis 2013; 1842:269-74. [PMID: 24326104 DOI: 10.1016/j.bbadis.2013.12.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 11/26/2013] [Accepted: 12/02/2013] [Indexed: 10/25/2022]
Abstract
Inherited thrombocytopenias are heterogeneous diseases caused by at least 20 genes playing different role in the processes of megakaryopoiesis and platelet production. Some forms, such as thrombocytopenia 4 (THC4), are very rare and not well characterized. THC4 is an autosomal dominant mild thrombocytopenia described in only one large family from New Zealand and due to a mutation (G41S) of the somatic isoform of the cytochrome c (CYCS) gene. We report a novel CYCS mutation (Y48H) in patients from an Italian family. Similar to individuals carrying G41S, they have platelets of normal size and morphology, which are only partially reduced in number, but no prolonged bleeding episodes. In order to determine the pathogenetic consequences of Y48H, we studied the effects of the two CYCS mutations in yeast and mouse cellular models. In both cases, we found reduction of respiratory level and increased apoptotic rate, supporting the pathogenetic role of CYCS in thrombocytopenia.
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Affiliation(s)
- Daniela De Rocco
- Department of Medical Sciences, University of Trieste, Trieste, Italy
| | - Cristina Cerqua
- Clinical Genetics Unit, Dept. of Woman and Child Health, University of Padova, IRP Città della Speranza, Padova, Italy
| | - Paola Goffrini
- Department of Life Sciences, University of Parma, Parma, Italy
| | - Giovanna Russo
- Division of Pediatric Hematology/Oncology, University of Catania, Catania, Italy
| | | | | | - Elena Nicchia
- Department of Medical Sciences, University of Trieste, Trieste, Italy
| | - Carlos T Moraes
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Alessandro Pecci
- Department of Internal Medicine, University of Pavia-IRCCS Policlinico San Matteo Foundation, Pavia, Italy
| | - Leonardo Salviati
- Clinical Genetics Unit, Dept. of Woman and Child Health, University of Padova, IRP Città della Speranza, Padova, Italy
| | - Anna Savoia
- Department of Medical Sciences, University of Trieste, Trieste, Italy; Institute for Maternal and Child Health-IRCCS Burlo Garofolo, Trieste, Italy.
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18
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Irwin MH, Parameshwaran K, Pinkert CA. Mouse models of mitochondrial complex I dysfunction. Int J Biochem Cell Biol 2012; 45:34-40. [PMID: 22903069 DOI: 10.1016/j.biocel.2012.08.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 07/21/2012] [Accepted: 08/04/2012] [Indexed: 12/21/2022]
Abstract
Diseases of the mitochondria generally affect cells with high-energy demand, and appear to most profoundly affect excitatory cells that have localized high energy requirements, such as neurons and cardiac and skeletal muscle cells. Complex I of the mammalian mitochondrial respiratory chain is a very large, 45 subunit enzyme, and functional deficiency of complex I is the most frequently observed cause of oxidative phosphorylation (OXPHOS) disorders. Impairment of complex I results in decreased cellular energy production and is responsible for a variety of human encephalopathies, myopathies and cardiomyopathies. Complex I deficiency may be caused by mutations in any of the seven mitochondrial or 38 nuclear genes that encode complex I subunits or by mutations in various other nuclear genes that affect complex I assembly or function. Mouse models that faithfully mimic human complex I disorders are needed to better understand the role of complex I in health and disease and for evaluation of potential therapies for mitochondrial diseases. In this review we discuss existing mouse models of mitochondrial complex I dysfunction, focusing on those with similarities to human mitochondrial disorders. We also discuss some of the noteworthy murine genetic models in which complex I genes are not disrupted, but complex I dysfunction is observed, along with some of the more popular chemical compounds that inhibit complex I function and are useful for modeling complex I deficiency in mice. This article is part of a Directed Issue entitled: Bioenergetic dysfunction, adaptation and therapy.
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Affiliation(s)
- Michael H Irwin
- Department of Pathobiology, Auburn University College of Veterinary Medicine, Auburn, AL, USA.
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19
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Khalimonchuk O, Kim H, Watts T, Perez-Martinez X, Winge DR. Oligomerization of heme o synthase in cytochrome oxidase biogenesis is mediated by cytochrome oxidase assembly factor Coa2. J Biol Chem 2012; 287:26715-26. [PMID: 22669974 DOI: 10.1074/jbc.m112.377200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The synthesis of the heme a cofactor used in cytochrome c oxidase (CcO) is dependent on the sequential action of heme o synthase (Cox10) and heme a synthase (Cox15). The active state of Cox10 appears to be a homo-oligomeric complex, and formation of this complex is dependent on the newly synthesized CcO subunit Cox1 and the presence of an early Cox1 assembly intermediate. Cox10 multimerization is triggered by progression of Cox1 from the early assembly intermediate to downstream intermediates. The CcO assembly factor Coa2 appears important in coupling the presence of newly synthesized Cox1 to Cox10 oligomerization. Cells lacking Coa2 are impaired in Cox10 complex formation as well as the formation of a high mass Cox15 complex. Increasing Cox1 synthesis in coa2Δ cells restores respiratory function if Cox10 protein levels are elevated. The C-terminal segment of Cox1 is important in triggering Cox10 oligomerization. Expression of the C-terminal 54 residues of Cox1 appended to a heterologous matrix protein leads to efficient Cox10 complex formation in coa2Δ cells, but it fails to induce Cox15 complex formation. The state of Cox10 was evaluated in mutants, which predispose human patients to CcO deficiency and the neurological disorder Leigh syndrome. The presence of the D336V mutation in the yeast Cox10 backbone results in a catalytically inactive enzyme that is fully competent to oligomerize. Thus, Cox10 oligomerization and catalytic activation are separate processes and can be uncoupled.
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Affiliation(s)
- Oleh Khalimonchuk
- Department of Medicine, University of Utah Health Sciences Center, Salt Lake City, Utah 84132, USA
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20
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Mitochondrial genome instability and ROS enhance intestinal tumorigenesis in APC(Min/+) mice. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 180:24-31. [PMID: 22056359 DOI: 10.1016/j.ajpath.2011.10.003] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2011] [Revised: 09/01/2011] [Accepted: 10/03/2011] [Indexed: 12/13/2022]
Abstract
Alterations in mitochondrial oxidative phosphorylation have long been documented in tumors. Other types of mitochondrial dysfunction, including altered reactive oxygen species (ROS) production and apoptosis, also can contribute to tumorigenesis and cancer phenotypes. Furthermore, mutation and altered amounts of mitochondrial DNA (mtDNA) have been observed in cancer cells. However, how mtDNA instability per se contributes to cancer remains largely undetermined. Mitochondrial transcription factor A (TFAM) is required for expression and maintenance of mtDNA. Tfam heterozygous knock-out (Tfam(+/-)) mice show mild mtDNA depletion, but have no overt phenotypes. We show that Tfam(+/-) mouse cells and tissues not only possess less mtDNA but also increased oxidative mtDNA damage. Crossing Tfam(+/-) mice to the adenomatous polyposis coli multiple intestinal neoplasia (APC(Min/+)) mouse cancer model revealed that mtDNA instability increases tumor number and growth in the small intestine. This was not a result of enhancement of Wnt/β-catenin signaling, but rather appears to involve a propensity for increased mitochondrial ROS production. Direct involvement of mitochondrial ROS in intestinal tumorigenesis was shown by crossing APC(Min/+) mice to those that have catalase targeted to mitochondria, which resulted in a significant reduction in tumorigenesis in the colon. Thus, mitochondrial genome instability and ROS enhance intestinal tumorigenesis and Tfam(+/-) mice are a relevant model to address the role of mtDNA instability in disease states in which mitochondrial dysfunction is implicated, such as cancer, neurodegeneration, and aging.
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Roestenberg P, Manjeri GR, Valsecchi F, Smeitink JAM, Willems PHGM, Koopman WJH. Pharmacological targeting of mitochondrial complex I deficiency: the cellular level and beyond. Mitochondrion 2011; 12:57-65. [PMID: 21757032 DOI: 10.1016/j.mito.2011.06.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 01/20/2011] [Accepted: 06/25/2011] [Indexed: 12/20/2022]
Abstract
Complex I (CI) represents a major entry point of electrons in the mitochondrial electron transport chain (ETC). It consists of 45 different subunits, encoded by the mitochondrial (mtDNA) and nuclear DNA (nDNA). In humans, mutations in nDNA-encoded subunits cause severe neurodegenerative disorders like Leigh Syndrome with onset in early childhood. The pathophysiological mechanism of these disorders is still poorly understood. Here we summarize the current knowledge concerning the consequences of nDNA-encoded CI mutations in patient-derived cells, present mouse models for human CI deficiency, and discuss potential treatment strategies for CI deficiency.
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Affiliation(s)
- Peggy Roestenberg
- Department of Biochemistry, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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22
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Levéen P, Kotarsky H, Mörgelin M, Karikoski R, Elmér E, Fellman V. The GRACILE mutation introduced into Bcs1l causes postnatal complex III deficiency: a viable mouse model for mitochondrial hepatopathy. Hepatology 2011; 53:437-47. [PMID: 21274865 DOI: 10.1002/hep.24031] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Accepted: 09/24/2010] [Indexed: 12/07/2022]
Abstract
UNLABELLED Mitochondrial dysfunction is an important cause for neonatal liver disease. Disruption of genes encoding oxidative phosphorylation (OXPHOS) components usually causes embryonic lethality, and thus few disease models are available. We developed a mouse model for GRACILE syndrome, a neonatal mitochondrial disease with liver and kidney involvement, caused by a homozygous BCS1L mutation (232A>G). This gene encodes a chaperone required for incorporation of Rieske iron-sulfur protein (RISP) into complex III of respiratory chain. Homozygous mutant mice after 3 weeks of age developed striking similarities to the human disease: growth failure, hepatic glycogen depletion, steatosis, fibrosis, and cirrhosis, as well as tubulopathy, complex III deficiency, lactacidosis, and short lifespan. BCS1L was decreased in whole liver cells and isolated mitochondria of mutants at all ages. RISP incorporation into complex III was diminished in symptomatic animals; however, in young animals complex III was correctly assembled. Complex III activity in liver, heart, and kidney of symptomatic mutants was decreased to 20%, 40%, and 40% of controls, respectively, as demonstrated with electron flux kinetics through complex III. In high-resolution respirometry, CIII dysfunction resulted in decreased electron transport capacity through the respiratory chain under maximum substrate input. Complex I function, suggested to be dependent on a functional complex III, was, however, unaffected. CONCLUSION We present the first viable model of complex III deficiency mimicking a human mitochondrial disorder. Incorporation of RISP into complex III in young homozygotes suggests another complex III assembly factor during early ontogenesis. The development of symptoms from about 3 weeks of age provides a convenient time window for studying the pathophysiology and treatment of mitochondrial hepatopathy and OXPHOS dysfunction in general.
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Affiliation(s)
- Per Levéen
- Department of Pediatrics, Clinical Sciences, Lund University, Lund, Sweden
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23
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Mazunin IO, Volodko NV, Starikovskaya EB, Sukernik RI. Mitochondrial genome and human mitochondrial diseases. Mol Biol 2010. [DOI: 10.1134/s0026893310050018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Early hippocampal oxidative stress is a direct consequence of seizures in the rapid electrical amygdala kindling model. Epilepsy Res 2010; 90:285-94. [DOI: 10.1016/j.eplepsyres.2010.06.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 05/18/2010] [Accepted: 06/10/2010] [Indexed: 11/23/2022]
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Perier C, Bové J, Dehay B, Jackson-Lewis V, Rabinovitch PS, Przedborski S, Vila M. Apoptosis-inducing factor deficiency sensitizes dopaminergic neurons to parkinsonian neurotoxins. Ann Neurol 2010; 68:184-92. [PMID: 20695011 DOI: 10.1002/ana.22034] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Mitochondrial complex I deficits have long been associated with Parkinson disease (PD). However, it remains unknown whether such defects represent a primary event in dopaminergic neurodegeneration. METHODS Apoptosis-inducing factor (AIF) is a mitochondrial protein that, independently of its proapoptotic properties, plays an essential physiologic role in maintaining a fully functional complex I. We used AIF-deficient harlequin (Hq) mice, which exhibit structural deficits in assembled complex I, to determine whether primary complex I defects linked to AIF depletion may cause dopaminergic neurodegeneration. RESULTS Despite marked reductions in mitochondrial complex I protein levels, Hq mice did not display apparent alterations in the dopaminergic nigrostriatal system. However, these animals were much more susceptible to exogenous parkinsonian complex I inhibitors, such as 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Subtoxic doses of MPTP, unable to cause damage to wild-type animals, produced marked nigrostriatal dopaminergic degeneration in Hq mice. This effect was associated with exacerbated complex I inhibition and increased production of mitochondrial-derived reactive oxygen species (ROS) in Hq brain mitochondria. The antioxidant superoxide dismutase-mimetic compound tempol was able to reverse the increased susceptibility of Hq mice to MPTP. Supporting an instrumental role for mitochondrial-derived ROS in PD-related neurodegeneration, transgenic mice overexpressing mitochondrially targeted catalase exhibited an attenuation of MPTP-induced mitochondrial ROS and dopaminergic cell death. INTERPRETATION Structural complex I alterations linked to AIF deficiency do not cause dopaminergic neurodegeneration but increase the susceptibility of dopaminergic neurons to exogenous parkinsonian neurotoxins, reinforcing the concept that genetic and environmental factors may interact in a common molecular pathway to trigger PD.
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Affiliation(s)
- Celine Perier
- Vall d'Hebron Research Institute and Center for Networked Biomedical Research on Neurodegenerative Diseases, Barcelona, Spain
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26
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Mitochondrial DNA mutations and human disease. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1797:113-28. [PMID: 19761752 DOI: 10.1016/j.bbabio.2009.09.005] [Citation(s) in RCA: 417] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Revised: 09/04/2009] [Accepted: 09/09/2009] [Indexed: 01/07/2023]
Abstract
Mitochondrial disorders are a group of clinically heterogeneous diseases, commonly defined by a lack of cellular energy due to oxidative phosphorylation (OXPHOS) defects. Since the identification of the first human pathological mitochondrial DNA (mtDNA) mutations in 1988, significant efforts have been spent in cataloguing the vast array of causative genetic defects of these disorders. Currently, more than 250 pathogenic mtDNA mutations have been identified. An ever-increasing number of nuclear DNA mutations are also being reported as the majority of proteins involved in mitochondrial metabolism and maintenance are nuclear-encoded. Understanding the phenotypic diversity and elucidating the molecular mechanisms at the basis of these diseases has however proved challenging. Progress has been hampered by the peculiar features of mitochondrial genetics, an inability to manipulate the mitochondrial genome, and difficulties in obtaining suitable models of disease. In this review, we will first outline the unique features of mitochondrial genetics before detailing the diseases and their genetic causes, focusing specifically on primary mtDNA genetic defects. The functional consequences of mtDNA mutations that have been characterised to date will also be discussed, along with current and potential future diagnostic and therapeutic advances.
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27
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Diaz F. Cytochrome c oxidase deficiency: patients and animal models. Biochim Biophys Acta Mol Basis Dis 2009; 1802:100-10. [PMID: 19682572 DOI: 10.1016/j.bbadis.2009.07.013] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2009] [Revised: 07/30/2009] [Accepted: 07/31/2009] [Indexed: 12/17/2022]
Abstract
Cytochrome c oxidase (COX) deficiencies are one of the most common defects of the respiratory chain found in mitochondrial diseases. COX is a multimeric inner mitochondrial membrane enzyme formed by subunits encoded by both the nuclear and the mitochondrial genome. COX biosynthesis requires numerous assembly factors that do not form part of the final complex but participate in prosthetic group synthesis and metal delivery in addition to membrane insertion and maturation of COX subunits. Human diseases associated with COX deficiency including encephalomyopathies, Leigh syndrome, hypertrophic cardiomyopathies, and fatal lactic acidosis are caused by mutations in COX subunits or assembly factors. In the last decade, numerous animal models have been created to understand the pathophysiology of COX deficiencies and the function of assembly factors. These animal models, ranging from invertebrates to mammals, in most cases mimic the pathological features of the human diseases.
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Affiliation(s)
- Francisca Diaz
- Department of Neurology, University of Miami Miller School of Medicine, 1095 NW 14th Terrace, Miami, Florida 33136, USA.
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28
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Amara CE, Marcinek DJ, Shankland EG, Schenkman KA, Arakaki LSL, Conley KE. Mitochondrial function in vivo: spectroscopy provides window on cellular energetics. Methods 2008; 46:312-8. [PMID: 18930151 PMCID: PMC10798296 DOI: 10.1016/j.ymeth.2008.10.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Revised: 10/03/2008] [Accepted: 10/08/2008] [Indexed: 01/06/2023] Open
Abstract
Mitochondria integrate the key metabolic fluxes in the cell. This role places this organelle at the center of cellular energetics and, hence, mitochondrial dysfunction underlies a growing number of human disorders and age-related degenerative diseases. Here we present novel analytical and technical methods for evaluating mitochondrial metabolism and (dys)function in human muscle in vivo. Three innovations involving advances in optical spectroscopy (OS) and magnetic resonance spectroscopy (MRS) permit quantifying key compounds in energy metabolism to yield mitochondrial oxidation and phosphorylation fluxes. The first of these uses analytical methods applied to optical spectra to measure hemoglobin (Hb) and myoglobin (Mb) oxygenation states and relative contents ([Hb]/[Mb]) to determine mitochondrial respiration (O2 uptake) in vivo. The second uses MRS methods to quantify key high-energy compounds (creatine phosphate, PCr, and adenosine triphosphate, ATP) to determine mitochondrial phosphorylation (ATP flux) in vivo. The third involves a functional test that combines these spectroscopic approaches to determine mitochondrial energy coupling (ATP/O2), phosphorylation capacity (ATP(max)) and oxidative capacity (O2max) of muscle. These new developments in optical and MR tools allow us to determine the function and capacity of mitochondria noninvasively in order to identify specific defects in vivo that are associated with disease in human and animal muscle. The clinical implication of this unique diagnostic probe is the insight into the nature and extent of dysfunction in metabolic and degenerative disorders, as well as the ability to follow the impact of interventions designed to reverse these disorders.
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Affiliation(s)
- Catherine E. Amara
- Department of Radiology, University of Washington Medical Center, Seattle, WA 98195
| | - David J. Marcinek
- Department of Radiology, University of Washington Medical Center, Seattle, WA 98195
| | - Eric G. Shankland
- Department of Radiology, University of Washington Medical Center, Seattle, WA 98195
| | - Kenneth A. Schenkman
- Department of Bioengineering, University of Washington Medical Center, Seattle, WA 98195
- Department of Pediatrics, University of Washington Medical Center, Seattle, WA 98195
| | - Lorilee S. L. Arakaki
- Department of Pediatrics, University of Washington Medical Center, Seattle, WA 98195
| | - Kevin E. Conley
- Department of Radiology, University of Washington Medical Center, Seattle, WA 98195
- Department of Physiology & Biophysics, University of Washington Medical Center, Seattle, WA 98195
- Department of Bioengineering, University of Washington Medical Center, Seattle, WA 98195
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