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Abstract
Mitochondrial optic neuropathies have a leading role in the field of mitochondrial medicine ever since 1988, when the first mutation in mitochondrial DNA was associated with Leber's hereditary optic neuropathy (LHON). Autosomal dominant optic atrophy (DOA) was subsequently associated in 2000 with mutations in the nuclear DNA affecting the OPA1 gene. LHON and DOA are both characterized by selective neurodegeneration of retinal ganglion cells (RGCs) triggered by mitochondrial dysfunction. This is centered on respiratory complex I impairment in LHON and defective mitochondrial dynamics in OPA1-related DOA, leading to distinct clinical phenotypes. LHON is a subacute, rapid, severe loss of central vision involving both eyes within weeks or months, with age of onset between 15 and 35 years old. DOA is a more slowly progressive optic neuropathy, usually apparent in early childhood. LHON is characterized by marked incomplete penetrance and a clear male predilection. The introduction of next-generation sequencing has greatly expanded the genetic causes for other rare forms of mitochondrial optic neuropathies, including recessive and X-linked, further emphasizing the exquisite sensitivity of RGCs to compromised mitochondrial function. All forms of mitochondrial optic neuropathies, including LHON and DOA, can manifest either as pure optic atrophy or as a more severe multisystemic syndrome. Mitochondrial optic neuropathies are currently at the forefront of a number of therapeutic programs, including gene therapy, with idebenone being the only approved drug for a mitochondrial disorder.
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Affiliation(s)
- Valerio Carelli
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy; IRCCS Istituto di Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy.
| | - Chiara La Morgia
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy; IRCCS Istituto di Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy
| | - Patrick Yu-Wai-Man
- John van Geest Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom; Cambridge Eye Unit, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, United Kingdom; Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom; Institute of Ophthalmology, University College London, London, United Kingdom
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López-Gallardo E, Emperador S, Hernández-Ainsa C, Montoya J, Bayona-Bafaluy MP, Ruiz-Pesini E. Food derived respiratory complex I inhibitors modify the effect of Leber hereditary optic neuropathy mutations. Food Chem Toxicol 2018; 120:89-97. [PMID: 29991444 DOI: 10.1016/j.fct.2018.07.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 06/21/2018] [Accepted: 07/05/2018] [Indexed: 01/14/2023]
Abstract
Mitochondrial DNA mutations in genes encoding respiratory complex I polypeptides can cause Leber hereditary optic neuropathy. Toxics affecting oxidative phosphorylation system can also cause mitochondrial optic neuropathy. Some complex I inhibitors found in edible plants might differentially interact with these pathologic mutations and modify their penetrance. To analyze this interaction, we have compared the effect of rotenone, capsaicin and rolliniastatin-1 on cybrids harboring the most frequent Leber hereditary optic neuropathy mutations and found that m.3460G > A mutation increases rotenone resistance but capsaicin and rolliniastatin-1 susceptibility. Thus, to explain the pathogenicity of mitochondrial diseases due to mitochondrial DNA mutations, their potential interactions with environment factors will have to be considered.
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Affiliation(s)
- Ester López-Gallardo
- Departamento de Bioquímica, Biología Molecular y Celular. Universidad de Zaragoza, Zaragoza, Spain; Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Zaragoza, Spain; Centro de Investigaciones Biomédicas En Red de Enfermedades Raras (CIBERER), Zaragoza, Spain.
| | - Sonia Emperador
- Departamento de Bioquímica, Biología Molecular y Celular. Universidad de Zaragoza, Zaragoza, Spain; Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Zaragoza, Spain; Centro de Investigaciones Biomédicas En Red de Enfermedades Raras (CIBERER), Zaragoza, Spain.
| | - Carmen Hernández-Ainsa
- Departamento de Bioquímica, Biología Molecular y Celular. Universidad de Zaragoza, Zaragoza, Spain; Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Zaragoza, Spain.
| | - Julio Montoya
- Departamento de Bioquímica, Biología Molecular y Celular. Universidad de Zaragoza, Zaragoza, Spain; Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Zaragoza, Spain; Centro de Investigaciones Biomédicas En Red de Enfermedades Raras (CIBERER), Zaragoza, Spain.
| | - M Pilar Bayona-Bafaluy
- Departamento de Bioquímica, Biología Molecular y Celular. Universidad de Zaragoza, Zaragoza, Spain; Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Zaragoza, Spain; Centro de Investigaciones Biomédicas En Red de Enfermedades Raras (CIBERER), Zaragoza, Spain.
| | - Eduardo Ruiz-Pesini
- Departamento de Bioquímica, Biología Molecular y Celular. Universidad de Zaragoza, Zaragoza, Spain; Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Zaragoza, Spain; Centro de Investigaciones Biomédicas En Red de Enfermedades Raras (CIBERER), Zaragoza, Spain; Fundación ARAID, Zaragoza, Spain.
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Fox DA. Retinal and visual system: occupational and environmental toxicology. HANDBOOK OF CLINICAL NEUROLOGY 2015; 131:325-40. [PMID: 26563796 DOI: 10.1016/b978-0-444-62627-1.00017-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Occupational chemical exposure often results in sensory systems alterations that occur without other clinical signs or symptoms. Approximately 3000 chemicals are toxic to the retina and central visual system. Their dysfunction can have immediate, long-term, and delayed effects on mental health, physical health, and performance and lead to increased occupational injuries. The aims of this chapter are fourfold. First, provide references on retinal/visual system structure, function, and assessment techniques. Second, discuss the retinal features that make it especially vulnerable to toxic chemicals. Third, review the clinical and corresponding experimental data regarding retinal/visual system deficits produced by occupational toxicants: organic solvents (carbon disulfide, trichloroethylene, tetrachloroethylene, styrene, toluene, and mixtures) and metals (inorganic lead, methyl mercury, and mercury vapor). Fourth, discuss occupational and environmental toxicants as risk factors for late-onset retinal diseases and degeneration. Overall, the toxicants altered color vision, rod- and/or cone-mediated electroretinograms, visual fields, spatial contrast sensitivity, and/or retinal thickness. The findings elucidate the importance of conducting multimodal noninvasive clinical, electrophysiologic, imaging and vision testing to monitor toxicant-exposed workers for possible retinal/visual system alterations. Finally, since the retina is a window into the brain, an increased awareness and understanding of retinal/visual system dysfunction should provide additional insight into acquired neurodegenerative disorders.
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Affiliation(s)
- Donald A Fox
- Departments of Vision Sciences, Biology and Biochemistry, Pharmacology, and Health and Human Performance, University of Houston, Houston, TX, USA.
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Federico A, Cardaioli E, Da Pozzo P, Formichi P, Gallus GN, Radi E. Mitochondria, oxidative stress and neurodegeneration. J Neurol Sci 2012; 322:254-62. [PMID: 22669122 DOI: 10.1016/j.jns.2012.05.030] [Citation(s) in RCA: 517] [Impact Index Per Article: 43.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 05/10/2012] [Accepted: 05/12/2012] [Indexed: 02/06/2023]
Abstract
Mitochondria are involved in ATP supply to cells through oxidative phosphorylation (OXPHOS), synthesis of key molecules and response to oxidative stress, as well as in apoptosis. They contain many redox enzymes and naturally occurring inefficiencies of oxidative phosphorylation generate reactive oxygen species (ROS). CNS functions depend heavily on efficient mitochondrial function, since brain tissue has a high energy demand. Mutations in mitochondrial DNA (mtDNA), generation and presence of ROS and environmental factors may contribute to energy failure and lead to neurodegenerative diseases. Many rare metabolic disorders have been associated with mitochondrial dysfunction. More than 300 pathogenic mtDNA mutations involve proteins that regulate OXPHOS and mitochondrial structural integrity, and have also been described in neurodegenerative diseases with autosomal inheritance. Mitochondria may have an important role in ageing-related neurodegenerative disorders like Parkinson's disease (PD), Alzheimer's disease (AD), Huntington's disease (HD) and amyotrophic lateral sclerosis (ALS). In primary mitochondrial and neurodegenerative disorders, there is strong evidence that mitochondrial dysfunction occurs early and has a primary role in pathogenesis. In the present review, we discuss several mitochondrial diseases as models of neurodegeneration.
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Affiliation(s)
- Antonio Federico
- Department of Neurological, Neurosurgical and Behavioural Sciences, Medical School, University of Siena, Italy.
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Kulkarni R, Marples B, Balasubramaniam M, Thomas RA, Tucker JD. Mitochondrial gene expression changes in normal and mitochondrial mutant cells after exposure to ionizing radiation. Radiat Res 2010; 173:635-44. [PMID: 20426663 DOI: 10.1667/rr1737.1] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Mitochondrial DNA (mtDNA) contains 13 genes that encode proteins of the oxidative phosphorylation complex that are involved in ATP generation. Leber's optic atrophy and Leigh's syndrome are diseases that are caused by point mutations in the mitochondrial genome and that have phenotypes associated with energy deprivation. We hypothesized that energy deficiency from mitochondrial mutations in these cells leads to radiation hypersensitivity. Here we compared mitochondrial gene expression for the 13 mitochondrial protein-coding genes in two mitochondrial mutant cell lines, GM13740 (Leigh's syndrome) and GM10744 (Leber's optic atrophy) and a normal human lymphoblastoid cell line (GM15036) after X irradiation (0-4 Gy) 0 to 24 h postirradiation. Changes in gene expression were compared with cellular radiosensitivity. Statistically significant differences between Leigh's syndrome and normal cells were found in mitochondrial gene expression for all radiation doses and times that were commensurate with changes in radiation sensitivity. The data suggest that Leigh's syndrome cells have an impaired ability to repair radiation-induced DNA damage that results in radiation hypersensitivity. This may be attributable to mitochondrial dysfunction from reductions in mitochondrial gene expression and ATP generation, since Leigh's optic atrophy cells exhibit a mutation in the ATPase6 gene, which is an important component of Complex V of ATP synthase. In contrast, the mutation of the Leber's cells conferred radioresistance, which might be attributed to the mutation in the ND4 gene in the mitochondrial genome. The altered sensitivity of mitochondrial mutant cells to ionizing radiation can lead to decreased DNA repair, which may put individuals with mtDNA mutations at greater risk for cancer and other diseases.
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Affiliation(s)
- Rohan Kulkarni
- Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202, USA
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Cardaioli E, Da Pozzo P, Gallus GN, Franceschini R, Rufa A, Dotti MT, Caporossi A, Federico A. Leber’s Hereditary Optic Neuropathy associated with cocaine, ecstasy and telithromycin consumption. J Neurol 2007; 254:255-6. [PMID: 17334960 DOI: 10.1007/s00415-006-0351-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2006] [Revised: 07/03/2006] [Accepted: 07/06/2006] [Indexed: 10/23/2022]
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Carelli V, Franceschini F, Venturi S, Barboni P, Savini G, Barbieri G, Pirro E, La Morgia C, Valentino ML, Zanardi F, Violante FS, Mattioli S. Grand rounds: could occupational exposure to n-hexane and other solvents precipitate visual failure in leber hereditary optic neuropathy? ENVIRONMENTAL HEALTH PERSPECTIVES 2007; 115:113-5. [PMID: 17366829 PMCID: PMC1797843 DOI: 10.1289/ehp.9245] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
CONTEXT Leber hereditary optic neuropathy (LHON) is a maternally inherited loss of central vision related to pathogenic mutations in the mitochondrial genome, which are a necessary but not sufficient condition to develop the disease. Investigation of precipitating environmental/occupational (and additional genetic) factors could be relevant for prevention. CASE PRESENTATION After a 6-month period of occupational exposure to n-hexane and other organic solvents, a 27-year-old man (a moderate smoker) developed an optic neuropathy. The patient had a full ophthalmologic and neurologic investigation, including standardized cycloergometer test for serum lactic acid levels and a skeletal muscle biopsy. His exposure history was also detailed, and he underwent genetic testing for LHON mitochondrial DNA mutations. The patient suffered a sequential optic neuropathy with the hallmarks of LHON and tested positive for the homoplasmic 11778G--> A/ND4 mutation. Routine laboratory monitoring revealed increased concentrations of urinary 2.5 hexandione (n-hexane metabolite) and hippuric acid (toluene metabolite) in the period immediately preceding the visual loss. DISCUSSION In a subject carrying an LHON mutation, the strict temporal sequence of prolonged appreciable occupational exposure followed by sudden onset of visual loss must raise a suspicion of causality (with a possible further interaction with tobacco smoke). RELEVANCE In this article, we add to the candidate occupational/environmental triggers of LHON and highlight the need for appropriate case-control (and laboratory) studies to validate the causal effect of mixed toxic exposures.
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Affiliation(s)
- Valerio Carelli
- Dipartimento di Scienze Neurologiche, Alma Mater Studiorum—University of Bologna, Bologna, Italy
| | - Flavia Franceschini
- Dipartimento di Sanità Pubblica, Azienda USL Bologna, San Giorgio di Piano, Bologna, Italy
| | - Silvia Venturi
- U.O. Medicina del Lavoro, Policlinico S.Orsola-Malpighi, Alma Mater Studiorum—University of Bologna, Bologna, Italy
| | | | | | - Giuseppe Barbieri
- Dipartimento di Sanità Pubblica, Azienda USL Bologna, San Giorgio di Piano, Bologna, Italy
| | - Ettore Pirro
- Dipartimento di Scienze Neurologiche, Alma Mater Studiorum—University of Bologna, Bologna, Italy
| | - Chiara La Morgia
- Dipartimento di Scienze Neurologiche, Alma Mater Studiorum—University of Bologna, Bologna, Italy
| | - Maria L. Valentino
- Dipartimento di Scienze Neurologiche, Alma Mater Studiorum—University of Bologna, Bologna, Italy
| | - Francesca Zanardi
- U.O. Medicina del Lavoro, Policlinico S.Orsola-Malpighi, Alma Mater Studiorum—University of Bologna, Bologna, Italy
| | - Francesco S. Violante
- U.O. Medicina del Lavoro, Policlinico S.Orsola-Malpighi, Alma Mater Studiorum—University of Bologna, Bologna, Italy
| | - Stefano Mattioli
- U.O. Medicina del Lavoro, Policlinico S.Orsola-Malpighi, Alma Mater Studiorum—University of Bologna, Bologna, Italy
- Address correspondence to S. Mattioli, Laboratorio di Epidemiologia, UO Medicina del Lavoro, Università di Bologna, Policlinico S. Orsola-Malpighi, via Pelagio Palagi, 9, 40138 Bologna, Italy. Telephone: 39-051-636-2932. Fax 39-051-636-2609. E-mail:
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