1
|
Gottschalk B, Madreiter-Sokolowski CT, Graier WF. Cristae junction as a fundamental switchboard for mitochondrial ion signaling and bioenergetics. Cell Calcium 2022; 101:102517. [PMID: 34915234 DOI: 10.1016/j.ceca.2021.102517] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 12/08/2021] [Indexed: 12/31/2022]
Abstract
OPA1 and MICU1 are both involved in the regulation of mitochondrial Ca2+ uptake and the stabilization of the cristae junction, which separates the inner mitochondrial membrane into the interboundary membrane and the cristae membrane. In this mini-review, we focus on the synergetic control of OPA1 and MICU1 on the cristae junction that serves as a fundamental regulator of multiple mitochondrial functions. In particular, we point to the critical role of an adaptive cristae junction permeability in mitochondrial Ca2+ signaling, spatial H+ gradients and mitochondrial membrane potential, metabolic activity, and apoptosis. These characteristics bear on a distinct localization of the oxidative phosphorylation machinery, the FoF1-ATPase, and mitochondrial Ca2+uniporter (MCU) within sections of the inner mitochondrial membrane isolated by the cristae junction and regulated by proteins like OPA1 and MICU1. We specifically focus on the impact of MICU1-regulated cristae junction on the activity and distribution of MCU within the complex ultrastructure of mitochondria.
Collapse
Affiliation(s)
- Benjamin Gottschalk
- Gottfried Schatz Research Center: Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, Graz, 8010 Austria
| | - Corina T Madreiter-Sokolowski
- Gottfried Schatz Research Center: Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, Graz, 8010 Austria
| | - Wolfgang F Graier
- Gottfried Schatz Research Center: Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, Graz, 8010 Austria; BioTechMed, Graz.
| |
Collapse
|
2
|
Hsu CL, Iwanowski P, Hsu CH, Kozubski W. Genetic diseases mimicking multiple sclerosis. Postgrad Med 2021; 133:728-749. [PMID: 34152933 DOI: 10.1080/00325481.2021.1945898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Multiple sclerosis (MS) is an inflammatory neurodegenerative disorder manifesting as gradual or progressive loss of neurological functions. Most patients present with relapsing-remitting disease courses. Extensive research over recent decades has expounded our insights into the presentations and diagnostic features of MS. Groups of genetic diseases, CADASIL and leukodystrophies, for example, have been frequently misdiagnosed with MS due to some overlapping clinical and radiological features. The delayed identification of these diseases in late adulthood can lead to severe neurological complications. Herein we discuss genetic diseases that have the potential to mimic multiple sclerosis, with highlights on clinical identification and practicing pearls that may aid physicians in recognizing MS-mimics with genetic background in clinical settings.
Collapse
Affiliation(s)
- Chueh Lin Hsu
- Department of Neurology, Poznan University of Medical Sciences, Poznan, Poland
| | - Piotr Iwanowski
- Department of Neurology, Poznan University of Medical Sciences, Poznan, Poland
| | - Chueh Hsuan Hsu
- Department of Neurology, China Medical University, Taichung, Taiwan
| | - Wojciech Kozubski
- Department of Neurology, Poznan University of Medical Sciences, Poznan, Poland
| |
Collapse
|
3
|
Sun S, Erchova I, Sengpiel F, Votruba M. Opa1 Deficiency Leads to Diminished Mitochondrial Bioenergetics With Compensatory Increased Mitochondrial Motility. Invest Ophthalmol Vis Sci 2021; 61:42. [PMID: 32561926 PMCID: PMC7415319 DOI: 10.1167/iovs.61.6.42] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Purpose Retinal ganglion cells (RGCs) are susceptible to mitochondrial deficits and also the major cell type affected in patients with mutations in the OPA1 gene in autosomal dominant optic atrophy (ADOA). Here, we characterized mitochondria in RGCs in vitro from a heterozygous B6; C3-Opa1Q285STOP (Opa1+/−) mouse model to investigate mitochondrial changes underlying the pathology in ADOA. Methods Mouse RGCs were purified from wild-type and Opa1+/− mouse retina by two-step immunopanning. The mitochondria in neurites of RGCs were labeled with MitoTracker Red for structure and motility measurement by time-lapse imaging. Mitochondrial bioenergetics were determined by the real-time measurement of oxygen consumption rate using a Seahorse XFe 96 Extracellular Flux Analyzer. Results We observed a significant decrease in mitochondrial length in Opa1+/− RGCs with a remarkably higher proportion and density of motile mitochondria along the neurites. We also observed an increased transport velocity with a higher number of contacts between mitochondria in Opa1+/− RGC neurites. The oxygen consumption assays showed a severe impairment in basal respiration, Adenosine triphosphate-linked (ATP-linked) oxygen consumption, as well as reserve respiratory capacity, in RGCs from Opa1+/− mouse retina. Conclusions Opa1 deficiency leads to significant fragmentation of mitochondrial morphology, activation of mitochondrial motility and impaired respiratory function in RGCs from the B6; C3-Opa1Q285STOP mouse model. This highlights the significant alterations in the intricate interplay between mitochondrial morphology, motility, and energy production in RGCs with Opa1 deficiency long before the onset of clinical symptoms of the pathology.
Collapse
|
4
|
Theocharopoulou G. The ubiquitous role of mitochondria in Parkinson and other neurodegenerative diseases. AIMS Neurosci 2020; 7:43-65. [PMID: 32455165 PMCID: PMC7242057 DOI: 10.3934/neuroscience.2020004] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 02/05/2020] [Indexed: 12/14/2022] Open
Abstract
Orderly mitochondrial life cycle, plays a key role in the pathology of neurodegenerative diseases. Mitochondria are ubiquitous in neurons as they respond to an ever-changing demand for energy supply. Mitochondria constantly change in shape and location, feature of their dynamic nature, which facilitates a quality control mechanism. Biological studies in mitochondria dynamics are unveiling the mechanisms of fission and fusion, which essentially arrange morphology and motility of these organelles. Control of mitochondrial network homeostasis is a critical factor for the proper function of neurons. Disease-related genes have been reported to be implicated in mitochondrial dysfunction. Increasing evidence implicate mitochondrial perturbation in neuronal diseases, such as AD, PD, HD, and ALS. The intricacy involved in neurodegenerative diseases and the dynamic nature of mitochondria point to the idea that, despite progress toward detecting the biology underlying mitochondrial disorders, its link to these diseases is difficult to be identified in the laboratory. Considering the need to model signaling pathways, both in spatial and temporal level, there is a challenge to use a multiscale modeling framework, which is essential for understanding the dynamics of a complex biological system. The use of computational models in order to represent both a qualitative and a quantitative structure of mitochondrial homeostasis, allows to perform simulation experiments so as to monitor the conformational changes, as well as the intersection of form and function.
Collapse
|
5
|
Bagli E, Zikou AK, Agnantis N, Kitsos G. Mitochondrial Membrane Dynamics and Inherited Optic Neuropathies. ACTA ACUST UNITED AC 2018; 31:511-525. [PMID: 28652416 DOI: 10.21873/invivo.11090] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 04/14/2017] [Accepted: 04/19/2017] [Indexed: 12/12/2022]
Abstract
Inherited optic neuropathies are a genetically diverse group of disorders mainly characterized by visual loss and optic atrophy. Since the first recognition of Leber's hereditary optic neuropathy, several genetic defects altering primary mitochondrial respiration have been proposed to contribute to the development of syndromic and non-syndromic optic neuropathies. Moreover, the genomics and imaging revolution in the past decade has increased diagnostic efficiency and accuracy, allowing recognition of a link between mitochondrial dynamics machinery and a broad range of inherited neurodegenerative diseases involving the optic nerve. Mutations of novel genes modifying mainly the balance between mitochondrial fusion and fission have been shown to lead to overlapping clinical phenotypes ranging from isolated optic atrophy to severe, sometimes lethal multisystem disorders, and are reviewed herein. Given the particular vulnerability of retinal ganglion cells to mitochondrial dysfunction, the accessibility of the eye as a part of the central nervous system and improvements in technical imaging concerning assessment of the retinal nerve fiber layer, optic nerve evaluation becomes critical - even in asymptomatic patients - for correct diagnosis, understanding and early treatment of these complex and enigmatic clinical entities.
Collapse
Affiliation(s)
- Eleni Bagli
- Institute of Molecular Biology and Biotechnology-FORTH, Division of Biomedical Research, Ioannina, Greece.,Department of Ophthalmology, University of Ioannina, Ioannina, Greece
| | - Anastasia K Zikou
- Department of Clinical Radiology, University of Ioannina, Ioannina, Greece
| | - Niki Agnantis
- Department of Pathology, University of Ioannina, Ioannina, Greece
| | - Georgios Kitsos
- Department of Ophthalmology, University of Ioannina, Ioannina, Greece
| |
Collapse
|
6
|
Kane MS, Alban J, Desquiret‐Dumas V, Gueguen N, Ishak L, Ferre M, Amati‐Bonneau P, Procaccio V, Bonneau D, Lenaers G, Reynier P, Chevrollier A. Autophagy controls the pathogenicity of OPA1 mutations in dominant optic atrophy. J Cell Mol Med 2017; 21:2284-2297. [PMID: 28378518 PMCID: PMC5618673 DOI: 10.1111/jcmm.13149] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 02/02/2017] [Indexed: 12/31/2022] Open
Abstract
Optic Atrophy 1 (OPA1) gene mutations cause diseases ranging from isolated dominant optic atrophy (DOA) to various multisystemic disorders. OPA1, a large GTPase belonging to the dynamin family, is involved in mitochondrial network dynamics. The majority of OPA1 mutations encodes truncated forms of the protein and causes DOA through haploinsufficiency, whereas missense OPA1 mutations are predicted to cause disease through deleterious dominant-negative mechanisms. We used 3D imaging and biochemical analysis to explore autophagy and mitophagy in fibroblasts from seven patients harbouring OPA1 mutations. We report new genotype-phenotype correlations between various types of OPA1 mutation and mitophagy. Fibroblasts bearing dominant-negative OPA1 mutations showed increased autophagy and mitophagy in response to uncoupled oxidative phosphorylation. In contrast, OPA1 haploinsufficiency was correlated with a substantial reduction in mitochondrial turnover and autophagy, unless subjected to experimental mitochondrial injury. Our results indicate distinct alterations of mitochondrial physiology and turnover in cells with OPA1 mutations, suggesting that the level and profile of OPA1 may regulate the rate of mitophagy.
Collapse
Affiliation(s)
- Mariame Selma Kane
- PREMMi/Mitochondrial Medicine Research CentreInstitut MITOVASCCNRS UMR 6015INSERM U1083Université d'Angers, CHU d'AngersAngersFrance
| | - Jennifer Alban
- PREMMi/Mitochondrial Medicine Research CentreInstitut MITOVASCCNRS UMR 6015INSERM U1083Université d'Angers, CHU d'AngersAngersFrance
| | - Valérie Desquiret‐Dumas
- PREMMi/Mitochondrial Medicine Research CentreInstitut MITOVASCCNRS UMR 6015INSERM U1083Université d'Angers, CHU d'AngersAngersFrance
- Département de Biochimie et GénétiqueCentre Hospitalier UniversitaireAngersFrance
| | - Naïg Gueguen
- PREMMi/Mitochondrial Medicine Research CentreInstitut MITOVASCCNRS UMR 6015INSERM U1083Université d'Angers, CHU d'AngersAngersFrance
- Département de Biochimie et GénétiqueCentre Hospitalier UniversitaireAngersFrance
| | - Layal Ishak
- RGM4645 Université Blaise PascalAubièreFrance
| | - Marc Ferre
- PREMMi/Mitochondrial Medicine Research CentreInstitut MITOVASCCNRS UMR 6015INSERM U1083Université d'Angers, CHU d'AngersAngersFrance
| | - Patrizia Amati‐Bonneau
- PREMMi/Mitochondrial Medicine Research CentreInstitut MITOVASCCNRS UMR 6015INSERM U1083Université d'Angers, CHU d'AngersAngersFrance
- Département de Biochimie et GénétiqueCentre Hospitalier UniversitaireAngersFrance
| | - Vincent Procaccio
- PREMMi/Mitochondrial Medicine Research CentreInstitut MITOVASCCNRS UMR 6015INSERM U1083Université d'Angers, CHU d'AngersAngersFrance
- Département de Biochimie et GénétiqueCentre Hospitalier UniversitaireAngersFrance
| | - Dominique Bonneau
- PREMMi/Mitochondrial Medicine Research CentreInstitut MITOVASCCNRS UMR 6015INSERM U1083Université d'Angers, CHU d'AngersAngersFrance
- Département de Biochimie et GénétiqueCentre Hospitalier UniversitaireAngersFrance
| | - Guy Lenaers
- PREMMi/Mitochondrial Medicine Research CentreInstitut MITOVASCCNRS UMR 6015INSERM U1083Université d'Angers, CHU d'AngersAngersFrance
| | - Pascal Reynier
- PREMMi/Mitochondrial Medicine Research CentreInstitut MITOVASCCNRS UMR 6015INSERM U1083Université d'Angers, CHU d'AngersAngersFrance
- Département de Biochimie et GénétiqueCentre Hospitalier UniversitaireAngersFrance
| | - Arnaud Chevrollier
- PREMMi/Mitochondrial Medicine Research CentreInstitut MITOVASCCNRS UMR 6015INSERM U1083Université d'Angers, CHU d'AngersAngersFrance
| |
Collapse
|
7
|
Nasca A, Scotton C, Zaharieva I, Neri M, Selvatici R, Magnusson OT, Gal A, Weaver D, Rossi R, Armaroli A, Pane M, Phadke R, Sarkozy A, Muntoni F, Hughes I, Cecconi A, Hajnóczky G, Donati A, Mercuri E, Zeviani M, Ferlini A, Ghezzi D. Recessive mutations in MSTO1 cause mitochondrial dynamics impairment, leading to myopathy and ataxia. Hum Mutat 2017; 38:970-977. [PMID: 28544275 PMCID: PMC5575512 DOI: 10.1002/humu.23262] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 05/10/2017] [Accepted: 05/12/2017] [Indexed: 12/30/2022]
Abstract
We report here the first families carrying recessive variants in the MSTO1 gene: compound heterozygous mutations were identified in two sisters and in an unrelated singleton case, who presented a multisystem complex phenotype mainly characterized by myopathy and cerebellar ataxia. Human MSTO1 is a poorly studied protein, suggested to have mitochondrial localization and to regulate morphology and distribution of mitochondria. As for other mutations affecting genes involved in mitochondrial dynamics, no biochemical defects typical of mitochondrial disorders were reported. Studies in patients’ fibroblasts revealed that MSTO1 protein levels were strongly reduced, the mitochondrial network was fragmented, and the fusion events among mitochondria were decreased, confirming the deleterious effect of the identified variants and the role of MSTO1 in modulating mitochondrial dynamics. We also found that MSTO1 is mainly a cytosolic protein. These findings indicate recessive mutations in MSTO1 as a new cause for inherited neuromuscular disorders with multisystem features.
Collapse
Affiliation(s)
- Alessia Nasca
- Molecular Neurogenetics Unit, Foundation IRCCS Neurological Institute Besta, Milan, Italy
| | - Chiara Scotton
- Medical Genetics Unit, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Irina Zaharieva
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Hospital, London, UK
| | - Marcella Neri
- Medical Genetics Unit, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Rita Selvatici
- Medical Genetics Unit, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | | | - Aniko Gal
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania.,Institute of Genomic Medicine and Rare Disorders, Semmelweis University, Budapest, Hungary
| | - David Weaver
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Rachele Rossi
- Medical Genetics Unit, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Annarita Armaroli
- Medical Genetics Unit, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Marika Pane
- Neuropsichiatry Unit, Catholic University, Policlinico Gemelli, Rome, Italy
| | - Rahul Phadke
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Hospital, London, UK
| | - Anna Sarkozy
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Hospital, London, UK
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Hospital, London, UK
| | - Imelda Hughes
- Royal Manchester Children's Hospital, Manchester, UK
| | - Antonella Cecconi
- Pediatrics Medical Genetics, Hospital S. Maria Annunziata Bagno a Ripoli, Florence, Italy
| | - György Hajnóczky
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Alice Donati
- Unit of Metabolic and Muscular Diseases, Meyer Children Hospital, Florence, Italy
| | - Eugenio Mercuri
- Neuropsichiatry Unit, Catholic University, Policlinico Gemelli, Rome, Italy
| | | | - Alessandra Ferlini
- Medical Genetics Unit, Department of Medical Sciences, University of Ferrara, Ferrara, Italy.,Dubowitz Neuromuscular Centre, UCL Great Ormond Street Hospital, London, UK
| | - Daniele Ghezzi
- Molecular Neurogenetics Unit, Foundation IRCCS Neurological Institute Besta, Milan, Italy
| |
Collapse
|
8
|
Cogliati S, Enriquez JA, Scorrano L. Mitochondrial Cristae: Where Beauty Meets Functionality. Trends Biochem Sci 2016; 41:261-273. [PMID: 26857402 DOI: 10.1016/j.tibs.2016.01.001] [Citation(s) in RCA: 523] [Impact Index Per Article: 65.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 01/07/2016] [Accepted: 01/08/2016] [Indexed: 01/30/2023]
Abstract
Mitochondrial cristae are dynamic bioenergetic compartments whose shape changes under different physiological conditions. Recent discoveries have unveiled the relation between cristae shape and oxidative phosphorylation (OXPHOS) function, suggesting that membrane morphology modulates the organization and function of the OXPHOS system, with a direct impact on cellular metabolism. As a corollary, cristae-shaping proteins have emerged as potential modulators of mitochondrial bioenergetics, a concept confirmed by genetic experiments in mouse models of respiratory chain deficiency. Here, we review our knowledge of mitochondrial ultrastructural organization and how it impacts mitochondrial metabolism.
Collapse
Affiliation(s)
- Sara Cogliati
- Centro Nacional de Investigaciònes Cardiovasculares Carlos III, Madrid, Spain
| | - Jose A Enriquez
- Centro Nacional de Investigaciònes Cardiovasculares Carlos III, Madrid, Spain; Departamento de Bioquímica, Universidad Zaragoza, Zaragoza, Spain
| | - Luca Scorrano
- Dulbecco Telethon Institute, Venetian Institute of Molecular Medicine, Padova, Italy; Department of Biology, University of Padova, Padova, Italy.
| |
Collapse
|
9
|
Abstract
Mitochondrial dynamics, fission and fusion, were first identified in yeast with investigation in heart cells beginning only in the last 5 to 7 years. In the ensuing time, it has become evident that these processes are not only required for healthy mitochondria, but also, that derangement of these processes contributes to disease. The fission and fusion proteins have a number of functions beyond the mitochondrial dynamics. Many of these functions are related to their membrane activities, such as apoptosis. However, other functions involve other areas of the mitochondria, such as OPA1's role in maintaining cristae structure and preventing cytochrome c leak, and its essential (at least a 10 kDa fragment of OPA1) role in mtDNA replication. In heart disease, changes in expression of these important proteins can have detrimental effects on mitochondrial and cellular function.
Collapse
Affiliation(s)
- A A Knowlton
- Molecular & Cellular Cardiology, Division of Cardiovascular Medicine and Pharmacology Department, University of California, Davis, and The Department of Veteran's Affairs, Northern California VA, Sacramento, California, USA
| | - T T Liu
- Molecular & Cellular Cardiology, Division of Cardiovascular Medicine and Pharmacology Department, University of California, Davis, and The Department of Veteran's Affairs, Northern California VA, Sacramento, California, USA
| |
Collapse
|
10
|
Measurement of Systemic Mitochondrial Function in Advanced Primary Open-Angle Glaucoma and Leber Hereditary Optic Neuropathy. PLoS One 2015; 10:e0140919. [PMID: 26496696 PMCID: PMC4619697 DOI: 10.1371/journal.pone.0140919] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 10/01/2015] [Indexed: 11/18/2022] Open
Abstract
Primary Open Angle Glaucoma (POAG) is a common neurodegenerative disease characterized by the selective and gradual loss of retinal ganglion cells (RGCs). Aging and increased intraocular pressure (IOP) are glaucoma risk factors; nevertheless patients deteriorate at all levels of IOP, implying other causative factors. Recent evidence presents mitochondrial oxidative phosphorylation (OXPHOS) complex-I impairments in POAG. Leber Hereditary Optic Neuropathy (LHON) patients suffer specific and rapid loss of RGCs, predominantly in young adult males, due to complex-I mutations in the mitochondrial genome. This study directly compares the degree of OXPHOS impairment in POAG and LHON patients, testing the hypothesis that the milder clinical disease in POAG is due to a milder complex-I impairment. To assess overall mitochondrial capacity, cells can be forced to produce ATP primarily from mitochondrial OXPHOS by switching the media carbon source to galactose. Under these conditions POAG lymphoblasts grew 1.47 times slower than controls, whilst LHON lymphoblasts demonstrated a greater degree of growth impairment (2.35 times slower). Complex-I enzyme specific activity was reduced by 18% in POAG lymphoblasts and by 29% in LHON lymphoblasts. We also assessed complex-I ATP synthesis, which was 19% decreased in POAG patients and 17% decreased in LHON patients. This study demonstrates both POAG and LHON lymphoblasts have impaired complex-I, and in the majority of aspects the functional defects in POAG were milder than LHON, which could reflect the milder disease development of POAG. This new evidence places POAG in the spectrum of mitochondrial optic neuropathies and raises the possibility for new therapeutic targets aimed at improving mitochondrial function.
Collapse
|
11
|
Bertholet AM, Delerue T, Millet AM, Moulis MF, David C, Daloyau M, Arnauné-Pelloquin L, Davezac N, Mils V, Miquel MC, Rojo M, Belenguer P. Mitochondrial fusion/fission dynamics in neurodegeneration and neuronal plasticity. Neurobiol Dis 2015; 90:3-19. [PMID: 26494254 DOI: 10.1016/j.nbd.2015.10.011] [Citation(s) in RCA: 245] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 09/16/2015] [Accepted: 10/13/2015] [Indexed: 12/17/2022] Open
Abstract
Mitochondria are dynamic organelles that continually move, fuse and divide. The dynamic balance of fusion and fission of mitochondria determines their morphology and allows their immediate adaptation to energetic needs, keeps mitochondria in good health by restoring or removing damaged organelles or precipitates cells in apoptosis in cases of severe defects. Mitochondrial fusion and fission are essential in mammals and their disturbances are associated with several diseases. However, while mitochondrial fusion/fission dynamics, and the proteins that control these processes, are ubiquitous, associated diseases are primarily neurological disorders. Accordingly, inactivation of the main actors of mitochondrial fusion/fission dynamics is associated with defects in neuronal development, plasticity and functioning, both ex vivo and in vivo. Here, we present the central actors of mitochondrial fusion and fission and review the role of mitochondrial dynamics in neuronal physiology and pathophysiology. Particular emphasis is placed on the three main actors of these processes i.e. DRP1,MFN1-2, and OPA1 as well as on GDAP1, a protein of the mitochondrial outer membrane preferentially expressed in neurons. This article is part of a Special Issue entitled: Mitochondria & Brain.
Collapse
Affiliation(s)
- A M Bertholet
- Université de Toulouse, Centre de Biologie du Développement, CNRS, UMR5547/Université Paul Sabatier, Toulouse, France; CNRS, Centre de Biologie du Développement, UMR5547/Université Paul Sabatier, Toulouse, France
| | - T Delerue
- Université de Toulouse, Centre de Biologie du Développement, CNRS, UMR5547/Université Paul Sabatier, Toulouse, France; CNRS, Centre de Biologie du Développement, UMR5547/Université Paul Sabatier, Toulouse, France
| | - A M Millet
- Université de Toulouse, Centre de Biologie du Développement, CNRS, UMR5547/Université Paul Sabatier, Toulouse, France; CNRS, Centre de Biologie du Développement, UMR5547/Université Paul Sabatier, Toulouse, France
| | - M F Moulis
- Université de Toulouse, Centre de Biologie du Développement, CNRS, UMR5547/Université Paul Sabatier, Toulouse, France; CNRS, Centre de Biologie du Développement, UMR5547/Université Paul Sabatier, Toulouse, France
| | - C David
- CNRS, Institut de Biochimie et Génétique Cellulaires (IBGC), UMR5095, Bordeaux, France; Université de Bordeaux, Institut de Biochimie et Génétique Cellulaires (IBGC), UMR5095, Bordeaux, France
| | - M Daloyau
- Université de Toulouse, Centre de Biologie du Développement, CNRS, UMR5547/Université Paul Sabatier, Toulouse, France; CNRS, Centre de Biologie du Développement, UMR5547/Université Paul Sabatier, Toulouse, France
| | - L Arnauné-Pelloquin
- Université de Toulouse, Centre de Biologie du Développement, CNRS, UMR5547/Université Paul Sabatier, Toulouse, France; CNRS, Centre de Biologie du Développement, UMR5547/Université Paul Sabatier, Toulouse, France
| | - N Davezac
- Université de Toulouse, Centre de Biologie du Développement, CNRS, UMR5547/Université Paul Sabatier, Toulouse, France; CNRS, Centre de Biologie du Développement, UMR5547/Université Paul Sabatier, Toulouse, France
| | - V Mils
- Université de Toulouse, Centre de Biologie du Développement, CNRS, UMR5547/Université Paul Sabatier, Toulouse, France; CNRS, Centre de Biologie du Développement, UMR5547/Université Paul Sabatier, Toulouse, France
| | - M C Miquel
- Université de Toulouse, Centre de Biologie du Développement, CNRS, UMR5547/Université Paul Sabatier, Toulouse, France; CNRS, Centre de Biologie du Développement, UMR5547/Université Paul Sabatier, Toulouse, France
| | - M Rojo
- CNRS, Institut de Biochimie et Génétique Cellulaires (IBGC), UMR5095, Bordeaux, France; Université de Bordeaux, Institut de Biochimie et Génétique Cellulaires (IBGC), UMR5095, Bordeaux, France.
| | - P Belenguer
- Université de Toulouse, Centre de Biologie du Développement, CNRS, UMR5547/Université Paul Sabatier, Toulouse, France; CNRS, Centre de Biologie du Développement, UMR5547/Université Paul Sabatier, Toulouse, France.
| |
Collapse
|
12
|
Heart failure and mitochondrial dysfunction: the role of mitochondrial fission/fusion abnormalities and new therapeutic strategies. J Cardiovasc Pharmacol 2014; 63:196-206. [PMID: 23884159 DOI: 10.1097/01.fjc.0000432861.55968.a6] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The treatment of heart failure (HF) has evolved during the past 30 years with the recognition of neurohormonal activation and the effectiveness of its inhibition in improving the quality of life and survival. Over the past 20 years, there has been a revolution in the investigation of the mitochondrion with the development of new techniques and the finding that mitochondria are connected in networks and undergo constant division (fission) and fusion, even in cardiac myocytes. This has led to new molecular and cellular discoveries in HF, which offer the potential for the development of new molecular-based therapies. Reactive oxygen species are an important cause of mitochondrial and cellular injury in HF, but there are other abnormalities, such as depressed mitochondrial fusion, that may eventually become the targets of at least episodic treatment. The overall need for mitochondrial fission/fusion balance may preclude sustained change in either fission or fusion. In this review, we will discuss the current HF therapy and its impact on the mitochondria. In addition, we will review some of the new drug targets under development. There is potential for effective, novel therapies for HF to arise from new molecular understanding.
Collapse
|
13
|
Marín-García J, Akhmedov AT, Moe GW. Mitochondria in heart failure: the emerging role of mitochondrial dynamics. Heart Fail Rev 2014; 18:439-56. [PMID: 22707247 DOI: 10.1007/s10741-012-9330-2] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Over the past decade, mitochondria have emerged as critical integrators of energy production, generation of reactive oxygen species (ROS), multiple cell death, and signaling pathways in the constantly beating heart. Clarification of the molecular mechanisms, underlying mitochondrial ROS generation and ROS-induced cell death pathways, associated with cardiovascular diseases, by itself remains an important aim; more recently, mitochondrial dynamics has emerged as an important active mechanism to maintain normal mitochondria number and morphology, both are necessary to preserve cardiomyocytes integrity. The two opposing processes, division (fission) and fusion, determine the cell type-specific mitochondrial morphology, the intracellular distribution and activity. The tightly controlled balance between fusion and fission is of particular importance in the high energy demanding cells, such as cardiomyocytes, skeletal muscles, and neuronal cells. A shift toward fission will lead to mitochondrial fragmentation, observed in quiescent cells, while a shift toward fusion will result in the formation of large mitochondrial networks, found in metabolically active cardiomyocytes. Defects in mitochondrial dynamics have been associated with various human disorders, including heart failure, ischemia reperfusion injury, diabetes, and aging. Despite significant progress in our understanding of the molecular mechanisms of mitochondrial function in the heart, further focused research is needed to translate this knowledge into the development of new therapies for various ailments.
Collapse
Affiliation(s)
- José Marín-García
- The Molecular Cardiology and Neuromuscular Institute, 75 Raritan Ave., Highland Park, NJ 08904, USA.
| | | | | |
Collapse
|
14
|
Van Bergen NJ, Blake RE, Crowston JG, Trounce IA. Oxidative phosphorylation measurement in cell lines and tissues. Mitochondrion 2014; 15:24-33. [DOI: 10.1016/j.mito.2014.03.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 03/06/2014] [Accepted: 03/10/2014] [Indexed: 01/01/2023]
|
15
|
Belenguer P, Pellegrini L. The dynamin GTPase OPA1: More than mitochondria? BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:176-83. [DOI: 10.1016/j.bbamcr.2012.08.004] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 08/01/2012] [Accepted: 08/03/2012] [Indexed: 12/24/2022]
|
16
|
Abstract
Mitochondria have been widely studied for their critical role in cellular metabolism, energy production, and cell death. New developments in research on mitochondria derived from studies in yeast have led to the discovery of entirely new mitochondrial processes that have implications for mitochondrial function in heart failure. Recent studies have identified that maintaining normal mitochondrial morphology and function depends on the dynamic balance of mitochondrial fusion and fission (division). Mitochondrial fusion and fission are constant ongoing processes, which are essential for the maintenance of normal mitochondrial function. Studies in heart failure have been limited but suggest a possible reduction in mitochondrial fusion. As mitochondrial fusion and fission have important links to apoptosis, a key mechanism of loss of cardiac myocytes in heart failure, there are many implications for both heart failure research and treatment.
Collapse
Affiliation(s)
- Le Chen
- Molecular and Cellular Cardiology Division, Department of Mediicine, University of California, Davis, CA, USA
| | | |
Collapse
|
17
|
Mitochondrial dynamics in cancer and neurodegenerative and neuroinflammatory diseases. Int J Cell Biol 2012; 2012:729290. [PMID: 22792111 PMCID: PMC3391904 DOI: 10.1155/2012/729290] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 04/12/2012] [Indexed: 11/18/2022] Open
Abstract
Mitochondria are key organelles in the cell, hosting essential functions, from biosynthetic and metabolic pathways, to oxidative phosphorylation and ATP production, from calcium buffering to red-ox homeostasis and apoptotic signalling pathways. Mitochondria are also dynamic organelles, continuously fusing and dividing, and their localization, size and trafficking are finely regulated. Moreover, in recent decades, alterations in mitochondrial function and dynamics have been implicated in an increasing number of diseases. In this review, we focus on the relationship clarified hitherto between mitochondrial dynamics and cancer, neurodegenerative and neuroinflammatory diseases.
Collapse
|
18
|
Piquereau J, Caffin F, Novotova M, Prola A, Garnier A, Mateo P, Fortin D, Huynh LH, Nicolas V, Alavi MV, Brenner C, Ventura-Clapier R, Veksler V, Joubert F. Down-regulation of OPA1 alters mouse mitochondrial morphology, PTP function, and cardiac adaptation to pressure overload. Cardiovasc Res 2012; 94:408-17. [PMID: 22406748 DOI: 10.1093/cvr/cvs117] [Citation(s) in RCA: 139] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
AIMS The optic atrophy 1 (OPA1) protein is an essential protein involved in the fusion of the mitochondrial inner membrane. Despite its high level of expression, the role of OPA1 in the heart is largely unknown. We investigated the role of this protein in Opa1(+/-) mice, having a 50% reduction in OPA1 protein expression in cardiac tissue. METHODS AND RESULTS In mutant mice, cardiac function assessed by echocardiography was not significantly different from that of the Opa1(+/+). Electron and fluorescence microscopy revealed altered morphology of the Opa1(+/-) mice mitochondrial network; unexpectedly, mitochondria were larger with the presence of clusters of fused mitochondria and altered cristae. In permeabilized mutant ventricular fibres, mitochondrial functional properties were maintained, but direct energy channelling between mitochondria and myofilaments was weakened. Importantly, the mitochondrial permeability transition pore (PTP) opening in isolated permeabilized cardiomyocytes and in isolated mitochondria was significantly less sensitive to mitochondrial calcium accumulation. Finally, 6 weeks after transversal aortic constriction, Opa1(+/-) hearts demonstrated hypertrophy almost two-fold higher (P< 0.01) than in wild-type mice with altered ejection fraction (decrease in 43 vs. 22% in Opa1(+/+) mice, P< 0.05). CONCLUSIONS These results suggest that, in adult cardiomyocytes, OPA1 plays an important role in mitochondrial morphology and PTP functioning. These properties may be critical for cardiac function under conditions of chronic pressure overload.
Collapse
Affiliation(s)
- Jerome Piquereau
- INSERM, U-769, Faculté de Pharmacie, Université Paris-Sud, 5 rue J-B Clément, F-92296 Châtenay-Malabry, France
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Schaaf CP, Blazo M, Lewis RA, Tonini RE, Takei H, Wang J, Wong LJ, Scaglia F. Early-onset severe neuromuscular phenotype associated with compound heterozygosity for OPA1 mutations. Mol Genet Metab 2011; 103:383-7. [PMID: 21636302 DOI: 10.1016/j.ymgme.2011.04.018] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 04/29/2011] [Accepted: 04/30/2011] [Indexed: 01/21/2023]
Abstract
INTRODUCTION Pathogenic mutations in the OPA1 gene are the most common identifiable cause of autosomal dominant optic atrophy (DOA), which is characterized by selective retinal ganglion cell loss, a distinctive pattern of temporal pallor of the optic nerve and a typical color vision deficit, with variable effects on visual acuity. Haploinsufficiency has been suggested as the major pathogenic mechanism for DOA. Here we present two siblings with severe ataxia, hypotonia, gastrointestinal dysmotility, dysphagia, and severe, early-onset optic atrophy who were found to be compound heterozygotes for two pathogenic OPA1 mutations. This example expands the clinical phenotype of OPA1-associated disorders and provides additional evidence for semi-dominant inheritance. METHODS AND RESULTS Molecular analysis of the OPA1 gene in this family by Sanger sequencing revealed compound heterozygosity for two mutations in trans configuration, a p.I382 M missense mutation and a p.V903GfsX3 frameshift deletion in both affected siblings. Electron microscopy of a skeletal muscle biopsy of the older sibling revealed dense osmiophilic bodies within the mitochondria. Mitochondrial DNA (mtDNA) content was within normal limits, and electron transport chain analysis showed no deficiencies of the mitochondrial respiratory chain enzymes. Multiple mtDNA deletions were not found. CONCLUSION Compound heterozygosity of pathogenic OPA1 mutations may cause severe neuromuscular phenotypes in addition to early-onset optic atrophy. While a role for OPA1 in mtDNA maintenance has been discussed, compound biallelic pathogenic OPA1 mutations in our patients did not result in altered mtDNA copy number, mtDNA deletions, or deficiencies of the electron transport chain, despite the severe clinical phenotype.
Collapse
Affiliation(s)
- Christian P Schaaf
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | | | | | | | | | | | | | | |
Collapse
|
20
|
Van Bergen NJ, Crowston JG, Kearns LS, Staffieri SE, Hewitt AW, Cohn AC, Mackey DA, Trounce IA. Mitochondrial oxidative phosphorylation compensation may preserve vision in patients with OPA1-linked autosomal dominant optic atrophy. PLoS One 2011; 6:e21347. [PMID: 21731710 PMCID: PMC3120866 DOI: 10.1371/journal.pone.0021347] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Accepted: 05/27/2011] [Indexed: 02/01/2023] Open
Abstract
Autosomal Dominant Optic Atrophy (ADOA) is the most common inherited optic atrophy where vision impairment results from specific loss of retinal ganglion cells of the optic nerve. Around 60% of ADOA cases are linked to mutations in the OPA1 gene. OPA1 is a fission-fusion protein involved in mitochondrial inner membrane remodelling. ADOA presents with marked variation in clinical phenotype and varying degrees of vision loss, even among siblings carrying identical mutations in OPA1. To determine whether the degree of vision loss is associated with the level of mitochondrial impairment, we examined mitochondrial function in lymphoblast cell lines obtained from six large Australian OPA1-linked ADOA pedigrees. Comparing patients with severe vision loss (visual acuity [VA]<6/36) and patients with relatively preserved vision (VA>6/9) a clear defect in mitochondrial ATP synthesis and reduced respiration rates were observed in patients with poor vision. In addition, oxidative phosphorylation (OXPHOS) enzymology in ADOA patients with normal vision revealed increased complex II+III activity and levels of complex IV protein. These data suggest that OPA1 deficiency impairs OXPHOS efficiency, but compensation through increases in the distal complexes of the respiratory chain may preserve mitochondrial ATP production in patients who maintain normal vision. Identification of genetic variants that enable this response may provide novel therapeutic insights into OXPHOS compensation for preventing vision loss in optic neuropathies.
Collapse
Affiliation(s)
- Nicole J. Van Bergen
- Centre for Eye Research Australia, University of Melbourne, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
| | - Jonathan G. Crowston
- Centre for Eye Research Australia, University of Melbourne, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
| | - Lisa S. Kearns
- Centre for Eye Research Australia, University of Melbourne, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
| | - Sandra E. Staffieri
- Centre for Eye Research Australia, University of Melbourne, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
| | - Alex W. Hewitt
- Centre for Eye Research Australia, University of Melbourne, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
| | - Amy C. Cohn
- Centre for Eye Research Australia, University of Melbourne, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
| | - David A. Mackey
- University of Western Australia, Perth, Western Australia, Australia
- Lions Eye Institute, Perth, Western Australia, Australia
| | - Ian A. Trounce
- Centre for Eye Research Australia, University of Melbourne, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
- * E-mail:
| |
Collapse
|
21
|
Lee S, Van Bergen NJ, Kong GY, Chrysostomou V, Waugh HS, O'Neill EC, Crowston JG, Trounce IA. Mitochondrial dysfunction in glaucoma and emerging bioenergetic therapies. Exp Eye Res 2010; 93:204-12. [PMID: 20691180 DOI: 10.1016/j.exer.2010.07.015] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Revised: 07/16/2010] [Accepted: 07/27/2010] [Indexed: 12/22/2022]
Abstract
The similarities between glaucoma and mitochondrial optic neuropathies have driven a growing interest in exploring mitochondrial function in glaucoma. The specific loss of retinal ganglion cells is a common feature of mitochondrial diseases - not only the classic mitochondrial optic neuropathies of Leber's Hereditary Optic Neuropathy and Autosomal Dominant Optic Atrophy - but also occurring together with more severe central nervous system involvement in many other syndromic mitochondrial diseases. The retinal ganglion cell, due to peculiar structural and energetic constraints, appears acutely susceptible to mitochondrial dysfunction. Mitochondrial function is also well known to decline with aging in post-mitotic tissues including neurons. Because age is a risk factor for glaucoma this adds another impetus to investigating mitochondria in this common and heterogeneous neurodegenerative disease. Mitochondrial function may be impaired by either nuclear gene or mitochondrial DNA genetic risk factors, by mechanical stress or chronic hypoperfusion consequent to the commonly raised intraocular pressure in glaucomatous eyes, or by toxic xenobiotic or even light-induced oxidative stress. If primary or secondary mitochondrial dysfunction is further established as contributing to glaucoma pathogenesis, emerging therapies aimed at optimizing mitochondrial function represent potentially exciting new clinical treatments that may slow retinal ganglion cell and vision loss in glaucoma.
Collapse
Affiliation(s)
- Shanjean Lee
- Centre for Eye Research Australia, University of Melbourne, Department of Ophthalmology, Royal Victorian Eye and Ear Hospital, 32 Gisborne Street East, Melbourne, Victoria 3002, Australia
| | | | | | | | | | | | | | | |
Collapse
|
22
|
Amati-Bonneau P, Milea D, Bonneau D, Chevrollier A, Ferré M, Guillet V, Gueguen N, Loiseau D, Crescenzo MAPD, Verny C, Procaccio V, Lenaers G, Reynier P. OPA1-associated disorders: Phenotypes and pathophysiology. Int J Biochem Cell Biol 2009; 41:1855-65. [DOI: 10.1016/j.biocel.2009.04.012] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Revised: 04/09/2009] [Accepted: 04/14/2009] [Indexed: 10/20/2022]
|
23
|
Liesa M, Palacín M, Zorzano A. Mitochondrial dynamics in mammalian health and disease. Physiol Rev 2009; 89:799-845. [PMID: 19584314 DOI: 10.1152/physrev.00030.2008] [Citation(s) in RCA: 685] [Impact Index Per Article: 45.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The meaning of the word mitochondrion (from the Greek mitos, meaning thread, and chondros, grain) illustrates that the heterogeneity of mitochondrial morphology has been known since the first descriptions of this organelle. Such a heterogeneous morphology is explained by the dynamic nature of mitochondria. Mitochondrial dynamics is a concept that includes the movement of mitochondria along the cytoskeleton, the regulation of mitochondrial architecture (morphology and distribution), and connectivity mediated by tethering and fusion/fission events. The relevance of these events in mitochondrial and cell physiology has been partially unraveled after the identification of the genes responsible for mitochondrial fusion and fission. Furthermore, during the last decade, it has been identified that mutations in two mitochondrial fusion genes (MFN2 and OPA1) cause prevalent neurodegenerative diseases (Charcot-Marie Tooth type 2A and Kjer disease/autosomal dominant optic atrophy). In addition, other diseases such as type 2 diabetes or vascular proliferative disorders show impaired MFN2 expression. Altogether, these findings have established mitochondrial dynamics as a consolidated area in cellular physiology. Here we review the most significant findings in the field of mitochondrial dynamics in mammalian cells and their implication in human pathologies.
Collapse
Affiliation(s)
- Marc Liesa
- Institute for Research in Biomedicine (IRB Barcelona), CIBER de Diabetes y Enfermedades Metabólicas Asociadas, and Departament de Bioquímica i Biologia Molecular, Universitat de Barcelona, Barcelona 08028, Spain
| | | | | |
Collapse
|
24
|
Abstract
AIMS Mitochondrial fusion and fission are essential processes for preservation of normal mitochondrial function. We hypothesized that fusion proteins would be decreased in heart failure (HF), as the mitochondria in HF have been reported to be small and dysfunctional. METHODS AND RESULTS Expression of optic atrophy 1 (OPA1), a mitochondrial fusion protein, was decreased in both human and rat HF, as observed by western blotting. OPA1 is important for maintaining normal cristae structure and function, for preserving the inner membrane structure and for protecting cells from apoptosis. Confocal and electron microscopy studies demonstrated that the mitochondria in the failing hearts were small and fragmented, consistent with decreased fusion. OPA1 mRNA levels did not differ between failing and normal hearts, suggesting post-transcriptional control. Simulated ischaemia in the cardiac myogenic cell line H9c2 cells reduced OPA protein levels. Reduction of OPA1 expression with shRNA resulted in increased apoptosis and fragmentation of the mitochondria. Overexpression of OPA1 increased mitochondrial tubularity, but did not protect against simulated ischaemia-induced apoptosis. Cytochrome c release from the mitochondria was increased both with reduction in OPA1 and with overexpression of OPA1. CONCLUSION This is the first report, to our knowledge, of changes in mitochondrial fusion/fission proteins in cardiovascular disease. These changes have implications for mitochondrial function and apoptosis, contributing to the cell loss which is part of the downward progression of the failing heart.
Collapse
Affiliation(s)
- Le Chen
- Molecular and Cellular Cardiology, Department of Medicine, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | | | | | | |
Collapse
|
25
|
OPA1 functions in mitochondria and dysfunctions in optic nerve. Int J Biochem Cell Biol 2009; 41:1866-74. [PMID: 19389483 DOI: 10.1016/j.biocel.2009.04.013] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Revised: 04/11/2009] [Accepted: 04/14/2009] [Indexed: 11/23/2022]
Abstract
OPA1 is the major gene responsible for Dominant Optic Atrophy (DOA), a blinding disease that affects specifically the retinal ganglion cells (RGCs), which function consists in connecting the neuro-retina to the brain. OPA1 encodes an intra-mitochondrial dynamin, involved in inner membrane structures and ubiquitously expressed, raising the critical question of the origin of the disease pathophysiology. Here, we review the fundamental knowledge on OPA1 functions and regulations, highlighting their involvements in mitochondrial respiration, membrane dynamic and apoptosis. In light of these functions, we then describe the remarkable RGC mitochondrial network physiology and analyse data collected from animal models expressing OPA1 mutations. If, to date RGC mitochondria does not present any peculiarity at the molecular level, they represent possible targets of numerous assaults, like light, pressure, oxidative stress and energetic impairment, which jeopardize their function and survival, as observed in OPA1 mouse models. Although fascinating fields of investigation are still to be addressed on OPA1 functions and on DOA pathophysiology, we have reached a conspicuous state of knowledge with pertinent cell and animal models, from which therapeutic trials can be initiated and deeply evaluated.
Collapse
|
26
|
Tang S, Le PK, Tse S, Wallace DC, Huang T. Heterozygous mutation of Opa1 in Drosophila shortens lifespan mediated through increased reactive oxygen species production. PLoS One 2009; 4:e4492. [PMID: 19221591 PMCID: PMC2637430 DOI: 10.1371/journal.pone.0004492] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Accepted: 12/19/2008] [Indexed: 12/03/2022] Open
Abstract
Optic atrophy 1 (OPA1) is a dynamin-like GTPase located in the inner mitochondrial membrane and mutations in OPA1 are associated with autosomal dominant optic atrophy (DOA). OPA1 plays important roles in mitochondrial fusion, cristae remodeling and apoptosis. Our previous study showed that dOpa1 mutation caused elevated reactive oxygen species (ROS) production and resulted in damage and death of the cone and pigment cells in Drosophila eyes. Since ROS-induced oxidative damage to the cells is one of the primary causes of aging, in this study, we examined the effects of heterozygous dOpa1 mutation on the lifespan. We found that heterozygous dOpa1 mutation caused shortened lifespan, increased susceptibility to oxidative stress and elevated production of ROS in the whole Drosophila. Antioxidant treatment partially restored lifespan in the male dOpa1 mutants, but had no effects in the females. Heterozygous dOpa1 mutation caused an impairment of respiratory chain complex activities, especially complexes II and III, and reversible decreased aconitase activity. Heterozygous dOpa1 mutation is also associated with irregular and dysmorphic mitochondria in the muscle. Our results, for the first time, demonstrate the important role of OPA1 in aging and lifespan, which is most likely mediated through augmented ROS production.
Collapse
Affiliation(s)
- Sha Tang
- Division of Human Genetics, Department of Pediatrics, University of California Irvine, Irvine, California, United States of America
| | - Phung Khanh Le
- Division of Human Genetics, Department of Pediatrics, University of California Irvine, Irvine, California, United States of America
| | - Stephanie Tse
- Division of Human Genetics, Department of Pediatrics, University of California Irvine, Irvine, California, United States of America
| | - Douglas C. Wallace
- Center for Molecular and Mitochondrial Medicine and Genetics, University of California Irvine, Irvine, California, United States of America
- Department of Biological Chemistry, University of California Irvine, Irvine, California, United States of America
| | - Taosheng Huang
- Division of Human Genetics, Department of Pediatrics, University of California Irvine, Irvine, California, United States of America
- Center for Molecular and Mitochondrial Medicine and Genetics, University of California Irvine, Irvine, California, United States of America
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, California, United States of America
- Department of Pathology, University of California Irvine, Irvine, California, United States of America
- * E-mail:
| |
Collapse
|