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Rigobello L, Lugli F, Caporali L, Bartocci A, Fadanni J, Zerbetto F, Iommarini L, Carelli V, Ghelli AM, Musiani F. A computational study to assess the pathogenicity of single or combinations of missense variants on respiratory complex I. Int J Biol Macromol 2024; 273:133086. [PMID: 38871105 DOI: 10.1016/j.ijbiomac.2024.133086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 06/07/2024] [Accepted: 06/09/2024] [Indexed: 06/15/2024]
Abstract
Variants found in the respiratory complex I (CI) subunit genes encoded by mitochondrial DNA can cause severe genetic diseases. However, it is difficult to establish a priori whether a single or a combination of CI variants may impact oxidative phosphorylation. Here we propose a computational approach based on coarse-grained molecular dynamics simulations aimed at investigating new CI variants. One of the primary CI variants associated with the Leber hereditary optic neuropathy (m.14484T>C/MT-ND6) was used as a test case and was investigated alone or in combination with two additional rare CI variants whose role remains uncertain. We found that the primary variant positioned in the E-channel region, which is fundamental for CI function, stiffens the enzyme dynamics. Moreover, a new mechanism for the transition between π- and α-conformation in the helix carrying the primary variant is proposed. This may have implications for the E-channel opening/closing mechanism. Finally, our findings show that one of the rare variants, located next to the primary one, further worsens the stiffening, while the other rare variant does not affect CI function. This approach may be extended to other variants candidate to exert a pathogenic impact on CI dynamics, or to investigate the interaction of multiple variants.
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Affiliation(s)
- Laura Rigobello
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna I-40127, Italy
| | - Francesca Lugli
- Department of Chemistry "Giacomo Ciamician", University of Bologna, Bologna I-40126, Italy.
| | - Leonardo Caporali
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna I-40124, Italy
| | - Alessio Bartocci
- Department of Physics, University of Trento, Trento I-38123, Italy; INFN-TIFPA, Trento Institute for Fundamental Physics and Applications, Trento I-38123, Italy
| | - Jacopo Fadanni
- Department of Chemistry "Giacomo Ciamician", University of Bologna, Bologna I-40126, Italy
| | - Francesco Zerbetto
- Department of Chemistry "Giacomo Ciamician", University of Bologna, Bologna I-40126, Italy
| | - Luisa Iommarini
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna I-40127, Italy
| | - Valerio Carelli
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna I-40124, Italy; Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna I-40123, Italy
| | - Anna Maria Ghelli
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna I-40127, Italy; IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna I-40124, Italy
| | - Francesco Musiani
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna I-40127, Italy.
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Peron C, Cavaliere A, Fasano C, Iannielli A, Spagnolo M, Legati A, Nicol Colombo M, Rizzo A, Sciacca FL, Carelli V, Broccoli V, Lamperti C, Tiranti V. Generation of iPSCs from identical twin, one affected by LHON and one unaffected, both carrying a combination of two mitochondrial variants: m.14484 T>C and m.10680G>A. Stem Cell Res 2024; 77:103406. [PMID: 38552355 DOI: 10.1016/j.scr.2024.103406] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 03/22/2024] [Accepted: 03/23/2024] [Indexed: 06/03/2024] Open
Abstract
Leber hereditary optic neuropathy (LHON) is one of the most common mitochondrial illness, causing retinal ganglion cell degeneration and central vision loss. It stems from point mutations in mitochondrial DNA (mtDNA), with key mutations being m.3460G > A, m.11778G > A, and m.14484 T > C. Fibroblasts from identical twins, sharing m.14484 T > C and m.10680G > A variants each with 70 % heteroplasmy, were used to generate iPSC lines. Remarkably, one twin, a LHON patient, displayed symptoms, while the other, a carrier, remained asymptomatic. These iPSCs offer a valuable tool for studying factors influencing disease penetrance and unravelling the role of m.10680G > A, which is still debated.
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Affiliation(s)
- Camille Peron
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Andrea Cavaliere
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Chiara Fasano
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Angelo Iannielli
- IRCCS San Raffaele Scientific Institute, Milan, Italy; National Research Council (CNR), Institute of Neuroscience, Milan, Italy
| | - Manuela Spagnolo
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Andrea Legati
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Maria Nicol Colombo
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Ambra Rizzo
- Laboratory of Clinical Investigation, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milan, Italy
| | - Francesca L Sciacca
- Laboratory of Clinical Investigation, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milan, Italy
| | - Valerio Carelli
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy; Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Vania Broccoli
- IRCCS San Raffaele Scientific Institute, Milan, Italy; National Research Council (CNR), Institute of Neuroscience, Milan, Italy
| | - Costanza Lamperti
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Valeria Tiranti
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy.
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Tagliani S, Malaventura C, Ceccato C, Parmeggiani F, Suppiej A. Leber Mitochondrial Optic Neuropathy in Pediatric Females With Focus on Very Early Onset Cases. J Child Neurol 2023; 38:5-15. [PMID: 36659874 DOI: 10.1177/08830738221149962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The aim of this study was to describe the phenotype of Leber hereditary optic neuropathy occurring in pediatric females. This disease generally affects young adult males, but it can occur also in females, and research data in this population is lacking. The very early onset can challenge the diagnosis and delay treatment. We searched PubMed through February 2021 and identified 226 pediatric females with genetically confirmed Leber hereditary optic neuropathy and added a new case of a 3-year-old female. The male-female ratio was 1.8:1; the mean onset age in females was 11 years with the onset at 3 years of age occurring in 3 females only. Acute onset with mild visual impairment was the most common presentation, associated with optic disc edema in 16%. Differential diagnoses are pseudotumor cerebri, optic nerve drusen and optic neuritis. The outcome is poor with partial recovery in 50%, despite some receiving Idebenone therapy.
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Affiliation(s)
- Sara Tagliani
- Department of Medical Sciences, Pediatric Section, University Hospital of Ferrara, Ferrara, Italy
| | - Cristina Malaventura
- Department of Medical Sciences, Pediatric Section, University Hospital of Ferrara, Ferrara, Italy
| | | | - Francesco Parmeggiani
- Department of Translational Medicine and for Romagna, 9299University of Ferrara, Ferrara, Italy.,ERN-EYE Network - Center for Retinitis Pigmentosa of Veneto Region, 196013Camposampiero Hospital, Padova, Italy
| | - Agnese Suppiej
- Department of Medical Sciences, Pediatric Section, University Hospital of Ferrara, Ferrara, Italy.,87812Robert Hollman Foundation, Padova, Italy.,ERN-EYE Network - Center for Retinitis Pigmentosa of Veneto Region, 196013Camposampiero Hospital, Padova, Italy
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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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Schultz DT, Eizenga JM, Corbett-Detig RB, Francis WR, Christianson LM, Haddock SH. Conserved novel ORFs in the mitochondrial genome of the ctenophore Beroe forskalii. PeerJ 2020; 8:e8356. [PMID: 32025367 PMCID: PMC6991124 DOI: 10.7717/peerj.8356] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 12/04/2019] [Indexed: 11/20/2022] Open
Abstract
To date, five ctenophore species' mitochondrial genomes have been sequenced, and each contains open reading frames (ORFs) that if translated have no identifiable orthologs. ORFs with no identifiable orthologs are called unidentified reading frames (URFs). If truly protein-coding, ctenophore mitochondrial URFs represent a little understood path in early-diverging metazoan mitochondrial evolution and metabolism. We sequenced and annotated the mitochondrial genomes of three individuals of the beroid ctenophore Beroe forskalii and found that in addition to sharing the same canonical mitochondrial genes as other ctenophores, the B. forskalii mitochondrial genome contains two URFs. These URFs are conserved among the three individuals but not found in other sequenced species. We developed computational tools called pauvre and cuttlery to determine the likelihood that URFs are protein coding. There is evidence that the two URFs are under negative selection, and a novel Bayesian hypothesis test of trinucleotide frequency shows that the URFs are more similar to known coding genes than noncoding intergenic sequence. Protein structure and function prediction of all ctenophore URFs suggests that they all code for transmembrane transport proteins. These findings, along with the presence of URFs in other sequenced ctenophore mitochondrial genomes, suggest that ctenophores may have uncharacterized transmembrane proteins present in their mitochondria.
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Affiliation(s)
- Darrin T. Schultz
- Department of Biomolecular Engineering and Bioinformatics, University of California Santa Cruz, Santa Cruz, CA, USA
- Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA
| | - Jordan M. Eizenga
- Department of Biomolecular Engineering and Bioinformatics, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Russell B. Corbett-Detig
- Department of Biomolecular Engineering and Bioinformatics, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Warren R. Francis
- Department of Biology, University of Southern Denmark, Odense, Denmark
| | | | - Steven H.D. Haddock
- Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
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6
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Clinical syndromes associated with mtDNA mutations: where we stand after 30 years. Essays Biochem 2018; 62:235-254. [DOI: 10.1042/ebc20170097] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 05/29/2018] [Accepted: 05/30/2018] [Indexed: 01/16/2023]
Abstract
The landmark year 1988 can be considered as the birthdate of mitochondrial medicine, when the first pathogenic mutations affecting mtDNA were associated with human diseases. Three decades later, the field still expands and we are not ‘scraping the bottom of the barrel’ yet. Despite the tremendous progress in terms of molecular characterization and genotype/phenotype correlations, for the vast majority of cases we still lack a deep understanding of the pathogenesis, good models to study, and effective therapeutic options. However, recent technological advances including somatic cell reprogramming to induced pluripotent stem cells (iPSCs), organoid technology, and tailored endonucleases provide unprecedented opportunities to fill these gaps, casting hope to soon cure the major primary mitochondrial phenotypes reviewed here. This group of rare diseases represents a key model for tackling the pathogenic mechanisms involving mitochondrial biology relevant to much more common disorders that affect our currently ageing population, such as diabetes and metabolic syndrome, neurodegenerative and inflammatory disorders, and cancer.
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Caporali L, Iommarini L, La Morgia C, Olivieri A, Achilli A, Maresca A, Valentino ML, Capristo M, Tagliavini F, Del Dotto V, Zanna C, Liguori R, Barboni P, Carbonelli M, Cocetta V, Montopoli M, Martinuzzi A, Cenacchi G, De Michele G, Testa F, Nesti A, Simonelli F, Porcelli AM, Torroni A, Carelli V. Peculiar combinations of individually non-pathogenic missense mitochondrial DNA variants cause low penetrance Leber's hereditary optic neuropathy. PLoS Genet 2018; 14:e1007210. [PMID: 29444077 PMCID: PMC5828459 DOI: 10.1371/journal.pgen.1007210] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 02/27/2018] [Accepted: 01/21/2018] [Indexed: 12/23/2022] Open
Abstract
We here report on the existence of Leber’s hereditary optic neuropathy (LHON) associated with peculiar combinations of individually non-pathogenic missense mitochondrial DNA (mtDNA) variants, affecting the MT-ND4, MT-ND4L and MT-ND6 subunit genes of Complex I. The pathogenic potential of these mtDNA haplotypes is supported by multiple evidences: first, the LHON phenotype is strictly inherited along the maternal line in one very large family; second, the combinations of mtDNA variants are unique to the two maternal lineages that are characterized by recurrence of LHON; third, the Complex I-dependent respiratory and oxidative phosphorylation defect is co-transferred from the proband’s fibroblasts into the cybrid cell model. Finally, all but one of these missense mtDNA variants cluster along the same predicted fourth E-channel deputed to proton translocation within the transmembrane domain of Complex I, involving the ND1, ND4L and ND6 subunits. Hence, the definition of the pathogenic role of a specific mtDNA mutation becomes blurrier than ever and only an accurate evaluation of mitogenome sequence variation data from the general population, combined with functional analyses using the cybrid cell model, may lead to final validation. Our study conclusively shows that even in the absence of a clearly established LHON primary mutation, unprecedented combinations of missense mtDNA variants, individually known as polymorphisms, may lead to reduced OXPHOS efficiency sufficient to trigger LHON. In this context, we introduce a new diagnostic perspective that implies the complete sequence analysis of mitogenomes in LHON as mandatory gold standard diagnostic approach. Leber’s hereditary optic neuropathy (LHON) is a common cause of maternally inherited vision loss. In the large majority of cases LHON is due to mitochondrial DNA (mtDNA) point mutations, clearly distinct from common polymorphisms normally found in the general population, affecting the mitochondrial function, thus defined as pathogenic. For the first time, we here demonstrate, on the genetic and functional ground, that unusual combinations of otherwise polymorphic and non-pathogenic mtDNA variants are sufficient for causing low-penetrance maternally inherited optic neuropathy in pedigrees fitting the LHON clinical diagnosis. Our findings bridge the blurry border between “pathogenic” and “neutral” mutations in an overall continuum that truly depends on the specific and sometime unique combination of variants characterizing each mitogenome. As a result, we conclude that, for an accurate diagnosis of LHON and possibly of other mitochondrial diseases, the only approach that can disclose all possible causative sources is complete mitogenome sequencing.
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Affiliation(s)
- Leonardo Caporali
- Neurology Unit, IRCCS Institute of Neurological Sciences of Bologna, Bologna, Italy
| | - Luisa Iommarini
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Bologna, Italy
| | - Chiara La Morgia
- Neurology Unit, IRCCS Institute of Neurological Sciences of Bologna, Bologna, Italy
- Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Anna Olivieri
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, Pavia, Italy
| | - Alessandro Achilli
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, Pavia, Italy
| | - Alessandra Maresca
- Neurology Unit, IRCCS Institute of Neurological Sciences of Bologna, Bologna, Italy
| | - Maria Lucia Valentino
- Neurology Unit, IRCCS Institute of Neurological Sciences of Bologna, Bologna, Italy
- Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | | | - Francesca Tagliavini
- Neurology Unit, IRCCS Institute of Neurological Sciences of Bologna, Bologna, Italy
| | - Valentina Del Dotto
- Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Claudia Zanna
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Bologna, Italy
| | - Rocco Liguori
- Neurology Unit, IRCCS Institute of Neurological Sciences of Bologna, Bologna, Italy
- Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | | | - Michele Carbonelli
- Neurology Unit, IRCCS Institute of Neurological Sciences of Bologna, Bologna, Italy
- Studio Oculistico D’Azeglio, Bologna, Italy
| | - Veronica Cocetta
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padua, Italy
| | - Monica Montopoli
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padua, Italy
| | - Andrea Martinuzzi
- IRCCS "E. Medea" Scientific Institute Conegliano-Pieve di Soligo Research Center, Pieve di Soligo, Italy
| | - Giovanna Cenacchi
- Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Giuseppe De Michele
- Department of Neuroscience, Reproductive Sciences and Dentistry, University of Naples “Federico II”, Naples, Italy
| | - Francesco Testa
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania “Luigi Vanvitelli”, Naples, Italy
| | - Anna Nesti
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania “Luigi Vanvitelli”, Naples, Italy
| | - Francesca Simonelli
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania “Luigi Vanvitelli”, Naples, Italy
| | - Anna Maria Porcelli
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Bologna, Italy
- Health Sciences & Technologies (HST) CIRI, University of Bologna, Bologna, Italy
| | - Antonio Torroni
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, Pavia, Italy
| | - Valerio Carelli
- Neurology Unit, IRCCS Institute of Neurological Sciences of Bologna, Bologna, Italy
- Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
- * E-mail:
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Caporali L, Maresca A, Capristo M, Del Dotto V, Tagliavini F, Valentino ML, La Morgia C, Carelli V. Incomplete penetrance in mitochondrial optic neuropathies. Mitochondrion 2017; 36:130-137. [PMID: 28716668 DOI: 10.1016/j.mito.2017.07.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 06/27/2017] [Accepted: 07/13/2017] [Indexed: 01/06/2023]
Abstract
Incomplete penetrance characterizes the two most frequent inherited optic neuropathies, Leber's Hereditary Optic Neuropathy (LHON) and dominant optic atrophy (DOA), due to genetic errors in the mitochondrial DNA (mtDNA) and the nuclear DNA (nDNA), respectively. For LHON, compelling evidence has accumulated on the complex interplay of mtDNA haplogroups and environmental interacting factors, whereas the nDNA remains essentially non informative. However, a compensatory mechanism of activated mitochondrial biogenesis and increased mtDNA copy number, possibly driven by a permissive nDNA background, is documented in LHON; when successful it maintains unaffected the mutation carriers, but in some individuals it might be hampered by tobacco smoking or other environmental factors, resulting in disease onset. In females, mitochondrial biogenesis is promoted and maintained within the compensatory range by estrogens, partially explaining the gender bias in LHON. Concerning DOA, none of the above mechanisms has been fully explored, thus mtDNA haplogroups, environmental factors such as tobacco and alcohol, and further nDNA variants may all participate as protective factors or, on the contrary, favor disease expression and severity. Next generation sequencing, complemented by transcriptomics and proteomics, may provide some answers in the next future, even if the multifactorial model that seems to apply to incomplete penetrance in mitochondrial optic neuropathies remains problematic, and careful stratification of patients will play a key role for data interpretation. The deep understanding of which factors impinge on incomplete penetrance may shed light on the pathogenic mechanisms leading to optic nerve atrophy, on their possible compensation and, thus, on development of therapeutic strategies.
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Affiliation(s)
- Leonardo Caporali
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy
| | - Alessandra Maresca
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy
| | | | - Valentina Del Dotto
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Italy
| | - Francesca Tagliavini
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy
| | - Maria Lucia Valentino
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy; Department of Biomedical and Neuromotor Sciences, University of Bologna, Italy
| | - Chiara La Morgia
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy; Department of Biomedical and Neuromotor Sciences, University of Bologna, Italy
| | - Valerio Carelli
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy; Department of Biomedical and Neuromotor Sciences, University of Bologna, Italy.
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Bi R, Logan I, Yao YG. Leber Hereditary Optic Neuropathy: A Mitochondrial Disease Unique in Many Ways. Handb Exp Pharmacol 2017; 240:309-336. [PMID: 27787713 DOI: 10.1007/164_2016_1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Leber hereditary optic neuropathy (LHON) was the first mitochondrial disease to be identified as being caused by mutations in the mitochondrial DNA (mtDNA). This disease has been studied extensively in the past two decades, particularly in Brazilian, Chinese and European populations; and many primary mutations have been reported. However, the disease is enigmatic with many unique features, and there still are several important questions to be resolved. The incomplete penetrance, the male-biased disease expression and the prevalence in young adults all defy a proper explanation. It has been reported that the development of LHON is affected by the interaction between mtDNA mutations, mtDNA haplogroup background, nuclear genes, environmental factors and epigenetics. Furthermore, with the help of new animal models for LHON that have been created in recent years, we are continuing to learn more about the mechanism of this disease. The stage has now been reached at which there is a good understanding of both the genetic basis of the disease and its epidemiology, but just how the blindness that follows from the death of cells in the optic nerve can be prevented remains to be a pharmacological challenge. In this chapter, we summarize the progress that has been made in various recent studies on LHON, focusing on the molecular pathogenic mechanisms, clinical features, biochemical effects, the pharmacology and its treatment.
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Affiliation(s)
- Rui Bi
- Division of Medical Genetics & Evolutionary Medicine, Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
| | | | - Yong-Gang Yao
- Division of Medical Genetics & Evolutionary Medicine, Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China.
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Whole mitochondrial genome analysis in South Indian patients with Leber's hereditary optic neuropathy. Mitochondrion 2016; 36:21-28. [PMID: 27989883 DOI: 10.1016/j.mito.2016.10.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 10/22/2016] [Accepted: 10/26/2016] [Indexed: 11/27/2022]
Abstract
Leber's hereditary optic neuropathy (LHON) is a mitochondrial DNA (mtDNA) associated neurodegenerative disorder of retinal ganglion cells. In this study, whole mitochondrial genome sequencing of 75 LHON patients and 40 controls was performed to identify the mutation frequency and haplogroup background of South Indian population. Analysis of mtDNA revealed 559 different variants in LHON patients, including 7 pathogenic mutations, 30 private, and 22 other disease associated variants. A significantly higher (p=0.0008) overall variation load per individual was noted among LHON patients versus controls. We reported for the first time, the association of M haplogroup (p=0.028) with LHON in this cohort.
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Pätsi J, Kervinen M, Kytövuori L, Majamaa K, Hassinen IE. Effects of pathogenic mutations in membrane subunits of mitochondrial Complex I on redox activity and proton translocation studied by modeling in Escherichia coli. Mitochondrion 2015; 22:23-30. [PMID: 25747201 DOI: 10.1016/j.mito.2015.02.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 02/19/2015] [Accepted: 02/24/2015] [Indexed: 01/12/2023]
Abstract
Effects of Complex I mutations were studied by modeling in NuoH, NuoJ or NuoK subunits of Escherichia coli NDH-1 by simultaneous optical monitoring of deamino-NADH oxidation and proton translocation and fitting to the data a model equation of transmembrane proton transport. A homolog of the ND1-E24 LHON/MELAS mutation caused 95% inhibition of d-NADH oxidation and proton translocation. The NuoJ-Y59F replacement decreased proton translocation. The NuoK-E72Q mutation lowered the enzyme activity, but proton pumping could be rescued by the double mutation NuoK-E72Q/I39D. Moving the NuoK-E72/E36 pair one helix turn towards the periplasm did not affect redox activity but decreased proton pumping.
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Affiliation(s)
- Jukka Pätsi
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, P.O. Box 5000, FIN-90014 Oulu, Finland.
| | - Marko Kervinen
- Department of Ophthalmology and Medical Research Center Oulu, Oulu University Hospital and University of Oulu, P.O. Box 5000, FIN-90014 Oulu, Finland.
| | - Laura Kytövuori
- Department of Neurology and Medical Research Center, Oulu University Hospital and University of Oulu, P.O. Box 5000, FIN-90014 Oulu, Finland.
| | - Kari Majamaa
- Department of Neurology and Medical Research Center, Oulu University Hospital and University of Oulu, P.O. Box 5000, FIN-90014 Oulu, Finland.
| | - Ilmo E Hassinen
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, P.O. Box 5000, FIN-90014 Oulu, Finland.
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Yang H, Liu R, Wang CC. Searching the co-occurrence of pathogenic mutations for Leber's hereditary optic neuropathy and hearing loss in more than 26,000 whole mitochondrial genomes. Mitochondrial DNA A DNA Mapp Seq Anal 2015; 27:3399-402. [PMID: 25714144 DOI: 10.3109/19401736.2015.1018239] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The co-occurrence of pathogenic or candidate mutations for Leber's hereditary optic neuropathy (LHON) and hearing loss has long been suggested to be a rare incident. The "rare" is probably caused by inadequate database searches. In this study, we created and released a comprehensive database with detailed information of haplogroup, variants, coding sites, and potential pathogenic mutations for more than 26,000 whole mitochondrial genomes. We found the co-occurrence in more than 200 individuals including not only LHON or hearing loss patients but also individuals sampled from general populations with various haplogroup backgrounds. The results highlighted the significant importance of adequate database searching in the genetic analysis of mitochondrial disorders.
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Affiliation(s)
- Haixin Yang
- a Department of Neurology , Liaocheng People's Hospital , Liaocheng , Shandong , P.R. China and
| | - Rui Liu
- b State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Contemporary Anthropology , Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University , Shanghai , P.R. China
| | - Chuan-Chao Wang
- b State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Contemporary Anthropology , Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University , Shanghai , P.R. China
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13
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Sadun AA, La Morgia C, Carelli V. Leber’s hereditary optic neuropathy: new quinone therapies change the paradigm. EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/eop.12.27] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Zhang AM, Jia X, Guo X, Zhang Q, Yao YG. Mitochondrial DNA mutation m.10680G > A is associated with Leber hereditary optic neuropathy in Chinese patients. J Transl Med 2012; 10:43. [PMID: 22400981 PMCID: PMC3372436 DOI: 10.1186/1479-5876-10-43] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Accepted: 03/09/2012] [Indexed: 01/01/2023] Open
Abstract
Background Leber hereditary optic neuropathy (LHON) is a mitochondrial disorder with gender biased and incomplete penetrance. The majority of LHON patients are caused by one of the three primary mutations (m.3460G > A, m.11778G > A and m.14484T > C). Rare pathogenic mutations have been occasionally reported in LHON patients. Methods We screened mutation m.10680G > A in the MT-ND4L gene in 774 Chinese patients with clinical features of LHON but lacked the three primary mutations by using allele specific PCR (AS-PCR). Patients with m.10680G > A were further determined entire mtDNA genome sequence. Results The optimal AS-PCR could detect as low as 10% heteroplasmy of mutation m.10680G > A. Two patients (Le1263 and Le1330) were identified to harbor m.10680G > A. Analysis of the complete mtDNA sequences of the probands suggested that they belonged to haplogroups B4a1 and D6a1. There was no other potentially pathogenic mutation, except for a few private yet reported variants in the MT-ND1 and MT-ND5 genes, in the two lineages. A search in reported mtDNA genome data set (n = 9277; excluding Chinese LHON patients) identified no individual with m.10680G > A. Frequency of m.10680G > A in Chinese LHON patients analyzed in this study and our previous studies (3/784) was significantly higher than that of the general populations (0/9277) (P = 0.0005). Conclusion Taken together, we speculated that m.10680G > A may be a rare pathogenic mutation for LHON in Chinese. This mutation should be included in future clinical diagnosis.
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Affiliation(s)
- A-Mei Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan 650223, China
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Czarnecka AM, Bartnik E. The role of the mitochondrial genome in ageing and carcinogenesis. J Aging Res 2011; 2011:136435. [PMID: 21403887 PMCID: PMC3042732 DOI: 10.4061/2011/136435] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Accepted: 01/03/2011] [Indexed: 01/01/2023] Open
Abstract
Mitochondrial DNA mutations and polymorphisms have been the focus of intensive investigations for well over a decade in an attempt to understand how they affect fundamental processes such as cancer and aging. Initial interest in mutations occurring in mitochondrial DNA of cancer cells diminished when most were found to be the same mutations which occurred during the evolution of human mitochondrial haplogroups. However, increasingly correlations are being found between various mitochondrial haplogroups and susceptibility to cancer or diseases in some cases and successful aging in others.
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Affiliation(s)
- Anna M. Czarnecka
- Laboratory of Molecular Oncology, Department of Oncology, Military Institute of Medicine, ul. Szaserów 128, 01-141 Warsaw, Poland
| | - Ewa Bartnik
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106, Warsaw, Poland
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland
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Leber's Hereditary Optic Neuropathy-Gene Therapy: From Benchtop to Bedside. J Ophthalmol 2010; 2011:179412. [PMID: 21253496 PMCID: PMC3021870 DOI: 10.1155/2011/179412] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 10/07/2010] [Accepted: 11/12/2010] [Indexed: 02/06/2023] Open
Abstract
Leber's hereditary optic neuropathy (LHON) is a maternally transmitted disorder caused by point mutations in mitochondrial DNA (mtDNA). Most cases are due to mutations in genes encoding subunits of the NADH-ubiquinone oxidoreductase that is Complex I of the electron transport chain (ETC). These mutations are located at nucleotide positions 3460, 11778, or 14484 in the mitochondrial genome. The disease is characterized by apoplectic, bilateral, and severe visual loss. While the mutated mtDNA impairs generation of ATP by all mitochondria, there is only a selective loss of retinal ganglion cells and degeneration of optic nerve axons. Thus, blindness is typically permanent. Half of the men and 10% of females who harbor the pathogenic mtDNA mutation actually develop the phenotype. This incomplete penetrance and gender bias is not fully understood. Additional mitochondrial and/or nuclear genetic factors may modulate the phenotypic expression of LHON. In a population-based study, the mtDNA background of haplogroup J was associated with an inverse relationship of low-ATP generation and increased production of reactive oxygen species (ROS). Effective therapy for LHON has been elusive. In this paper, we describe the findings of pertinent published studies and discuss the controversies of potential strategies to ameliorate the disease.
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Yu D, Jia X, Zhang AM, Li S, Zou Y, Zhang Q, Yao YG. Mitochondrial DNA sequence variation and haplogroup distribution in Chinese patients with LHON and m.14484T>C. PLoS One 2010; 5:e13426. [PMID: 20976138 PMCID: PMC2956641 DOI: 10.1371/journal.pone.0013426] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Accepted: 09/22/2010] [Indexed: 12/28/2022] Open
Abstract
Background Leber hereditary optic neuropathy (LHON, MIM 535000) is one of the most common mitochondrial genetic disorders caused by three primary mtDNA mutations (m.3460G>A, m.11778G>A and m. 14484T>C). The clinical expression of LHON is affected by many additional factors, e.g. mtDNA background, nuclear genes, and environmental factors. Hitherto, there is no comprehensive study of Chinese LHON patients with m.14484T>C. Methodology/Principal Findings In this study, we analyzed the mtDNA sequence variations and haplogroup distribution pattern of the largest number of Chinese LHON patients with m.14484T>C to date. We first determined the complete mtDNA sequences in eleven LHON probands with m.14484T>C, to discern the potentially pathogenic mutations that co-segregate with m.14484T>C. We then dissected the matrilineal structure of 52 patients with m.14484T>C (including 14 from unrelated families and 38 sporadic cases) and compared it with the reported Han Chinese from general populations. Complete mtDNA sequencing showed that the eleven matrilines belonged to nine haplogroups including Y2, C4a, M8a, M10a1a, G1a1, G2a1, G2b2, D5a2a1, and D5c. We did not identify putatively pathogenic mutation that was co-segregated with m.14484T>C in these lineages based on the evolutionary analysis. Compared with the reported Han Chinese from general populations, the LHON patients with m.14484T>C had significantly higher frequency of haplogroups C, G, M10, and Y, but a lower frequency of haplogroup F. Intriguingly, we also observed a lower prevalence of F lineages in LHON subjects with m.11778G>A in our previous study, suggesting that this haplogroup may enact similar role during the onset of LHON in the presence of m.14484T>C or m.11778G>A. Conclusions/Significance Our current study provided a comprehensive profile regarding the mtDNA variation and background of Chinese patients with LHON and m.14484T>C. Matrilineal background might affect the expression of LHON in Chinese patients with m.14484T>C.
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Affiliation(s)
- Dandan Yu
- Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Xiaoyun Jia
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - A-Mei Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
- Graduate School of the Chinese Academy of Sciences, Beijing, China
| | - Shiqiang Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Yang Zou
- Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
- Graduate School of the Chinese Academy of Sciences, Beijing, China
| | - Qingjiong Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
- * E-mail: (Y-GY); (QZ)
| | - Yong-Gang Yao
- Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
- * E-mail: (Y-GY); (QZ)
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Zou Y, Jia X, Zhang AM, Wang WZ, Li S, Guo X, Kong QP, Zhang Q, Yao YG. The MT-ND1 and MT-ND5 genes are mutational hotspots for Chinese families with clinical features of LHON but lacking the three primary mutations. Biochem Biophys Res Commun 2010; 399:179-85. [DOI: 10.1016/j.bbrc.2010.07.051] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Accepted: 07/15/2010] [Indexed: 02/03/2023]
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Yang J, Zhu Y, Chen L, Zhang H, Tong Y, Huang D, Zhang Z, Chen S, Han X, Ma X. Novel A14841G mutation is associated with high penetrance of LHON/C4171A family. Biochem Biophys Res Commun 2009; 386:693-6. [DOI: 10.1016/j.bbrc.2009.06.102] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2009] [Accepted: 06/17/2009] [Indexed: 10/20/2022]
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Yang J, Zhu Y, Tong Y, Chen L, Liu L, Zhang Z, Wang X, Huang D, Qiu W, Zhuang S, Ma X. Confirmation of the mitochondrial ND1 gene mutation G3635A as a primary LHON mutation. Biochem Biophys Res Commun 2009; 386:50-4. [DOI: 10.1016/j.bbrc.2009.05.127] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Accepted: 05/28/2009] [Indexed: 01/30/2023]
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