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Lambiri DW, Levin LA. Maculopapillary Bundle Degeneration in Optic Neuropathies. Curr Neurol Neurosci Rep 2024:10.1007/s11910-024-01343-0. [PMID: 38833037 DOI: 10.1007/s11910-024-01343-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/16/2024] [Indexed: 06/06/2024]
Abstract
PURPOSE OF REVIEW Degeneration of the maculopapillary bundle (MPB) is a prominent feature in a spectrum of optic neuropathies. MPB-selective degeneration is seen in specific conditions, such as nutritional and toxic optic neuropathies, Leber hereditary optic neuropathy (LHON), and dominant optic atrophy (DOA). Despite their distinct etiologies and clinical presentations, which encompass variations in age of incidence and monocular or binocular onset, these disorders share a core molecular mechanism: compromised mitochondrial homeostasis. This disruption is characterized by dysfunctions in mitochondrial metabolism, biogenesis, and protein synthesis. This article provides a comprehensive understanding of the MPB's role in optic neuropathies, emphasizing the importance of mitochondrial mechanisms in the pathogenesis of these conditions. RECENT FINDINGS Optical coherence tomography studies have characterized the retinal nerve fiber layer changes accompanying mitochondrial-affiliated optic neuropathies. Selective thinning of the temporal optic nerve head is preceded by thickening in early stages of these disorders which correlates with reductions in macular ganglion cell layer thinning and vascular atrophy. A recently proposed mechanism underpinning the selective atrophy of the MPB involves the positive feedback of reactive oxygen species generation as a common consequence of mitochondrial dysfunction. Additionally, new research has revealed that the MPB can undergo degeneration in the early stages of glaucoma, challenging the historically held belief that this area was not involved in this common optic neuropathy. A variety of anatomical risk factors influence the propensity of glaucomatous MPB degeneration, and cases present distinct patterns of ganglion cell degeneration that are distinct from those observed in mitochondria-associated diseases. This review synthesizes clinical and molecular research on primary MPB disorders, highlighting the commonalities and differences in their pathogenesis. KEY POINTS (BOX) 1. Temporal degeneration of optic nerve fibers accompanied by cecocentral scotoma is a hallmark of maculopapillary bundle (MPB) degeneration. 2. Mechanisms of MPB degeneration commonly implicate mitochondrial dysfunction. 3. Recent research challenges the traditional belief that the MPB is uninvolved in glaucoma by showing degeneration in the early stages of this common optic neuropathy, yet with features distinct from other MPB-selective neuropathies. 4. Reactive oxygen species generation is a mechanism linking mitochondrial mechanisms of MPB-selective optic neuropathies, but in-vivo and in-vitro studies are needed to validate this hypothesis.
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Affiliation(s)
- Darius W Lambiri
- Faculty of Medicine and Health Sciences, McGill University, Montreal, Canada
- Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada
| | - Leonard A Levin
- Faculty of Medicine and Health Sciences, McGill University, Montreal, Canada.
- Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada.
- Department of Neurology & Neurosurgery, McGill University, Montreal, Canada.
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Borrelli E, Bandello F, Boon CJF, Carelli V, Lenaers G, Reibaldi M, Sadda SR, Sadun AA, Sarraf D, Yu-Wai-Man P, Barboni P. Mitochondrial retinopathies and optic neuropathies: The impact of retinal imaging on modern understanding of pathogenesis, diagnosis, and management. Prog Retin Eye Res 2024; 101:101264. [PMID: 38703886 DOI: 10.1016/j.preteyeres.2024.101264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 03/18/2024] [Accepted: 04/26/2024] [Indexed: 05/06/2024]
Abstract
Advancements in ocular imaging have significantly broadened our comprehension of mitochondrial retinopathies and optic neuropathies by examining the structural and pathological aspects of the retina and optic nerve in these conditions. This article aims to review the prominent imaging characteristics associated with mitochondrial retinopathies and optic neuropathies, aiming to deepen our insight into their pathogenesis and clinical features. Preceding this exploration, the article provides a detailed overview of the crucial genetic and clinical features, which is essential for the proper interpretation of in vivo imaging. More importantly, we will provide a critical analysis on how these imaging modalities could serve as biomarkers for characterization and monitoring, as well as in guiding treatment decisions. However, these imaging methods have limitations, which will be discussed along with potential strategies to mitigate them. Lastly, the article will emphasize the potential advantages and future integration of imaging techniques in evaluating patients with mitochondrial eye disorders, considering the prospects of emerging gene therapies.
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Affiliation(s)
- Enrico Borrelli
- Department of Surgical Sciences, University of Turin, Turin, Italy; Department of Ophthalmology, "City of Health and Science" Hospital, Turin, Italy.
| | - Francesco Bandello
- Vita-Salute San Raffaele University, Milan, Italy; IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Camiel J F Boon
- Department of Ophthalmology, Amsterdam University Medical Centers, Amsterdam, the Netherlands; Department of Ophthalmology, Leiden University Medical Center, Leiden, the Netherlands
| | - Valerio Carelli
- Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy; IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy
| | - Guy Lenaers
- Equipe MitoLab, Unité MitoVasc, INSERM U1083, Université d'Angers, 49933, Angers, France; Service de Neurologie, CHU d'Angers, 49100, Angers, France
| | - Michele Reibaldi
- Department of Surgical Sciences, University of Turin, Turin, Italy; Department of Ophthalmology, "City of Health and Science" Hospital, Turin, Italy
| | - Srinivas R Sadda
- Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Doheny Eye Institute, Los Angeles, CA, USA
| | - Alfredo A Sadun
- Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Doheny Eye Institute, Los Angeles, CA, USA
| | - David Sarraf
- Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Retinal Disorders and Ophthalmic Genetics Division, Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Patrick Yu-Wai-Man
- John van Geest Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Cambridge Eye Unit, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK; Institute of Ophthalmology, University College London, London, UK
| | - Piero Barboni
- IRCCS San Raffaele Scientific Institute, Milan, Italy; Studio Oculistico d'Azeglio, Bologna, Italy.
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Lombardo M, Cusumano A, Mancino R, Aiello F, Sorge RP, Nucci C, Cesareo M. Short Wavelength Automated Perimetry, Standard Automated Perimetry, and Optical Coherence Tomography in Dominant Optic Atrophy. J Clin Med 2024; 13:1971. [PMID: 38610740 PMCID: PMC11012462 DOI: 10.3390/jcm13071971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 02/19/2024] [Accepted: 03/27/2024] [Indexed: 04/14/2024] Open
Abstract
Background: Blue-yellow axis dyschromatopsia is well-known in Autosomal Dominant Optic Atrophy (ADOA) patients, but there were no data on the correlation between retinal structure and short-wavelength automated perimetry (SWAP) values in this pathology. Methods: In this cross-sectional case-control study, we assessed the correlation between best corrected visual acuity (BCVA), standard automated perimetry (SAP), SWAP, and optical coherence tomography (OCT) parameters of 9 ADOA patients compared with healthy controls. Correlation analysis was performed between BCVA, mean deviation, pattern standard deviation (PSD), and fovea sensitivity (FS) values and the OCT thickness of each retinal layer and the peripapillary retinal nerve fiber layer (pRNFL). Results: The following significant and strong correlations were found: between BCVA and ganglion cell layer (GCL) and the global (G) pRNFL thicknesses; between SAP FS and GCL and the G-pRNFL thicknesses; between SWAP PSD and total retina, GCL, inner plexiform layer, inner nuclear layer, inner retinal layer and the temporal pRNFL thicknesses. We found a constant shorter duration of the SITA-SWAP compared with the SITA-STANDARD strategy. Conclusions: SWAP, SAP, and BCVA values provided relevant clinical information about retinal involvement in our ADOA patients. The perimetric functional parameters that seemed to correlate better with structure involvement were FS on SAP and PSD on SWAP.
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Affiliation(s)
- Marco Lombardo
- Ophthalmology Unit, Department of Experimental Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Andrea Cusumano
- Ophthalmology Unit, Department of Experimental Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Raffaele Mancino
- Ophthalmology Unit, Department of Experimental Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Francesco Aiello
- Ophthalmology Unit, Department of Experimental Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Roberto Pietro Sorge
- Laboratory of Biometry, Department of Systems Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Carlo Nucci
- Ophthalmology Unit, Department of Experimental Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Massimo Cesareo
- Ophthalmology Unit, Department of Experimental Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
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Ge JY, Teo ZL, Loo JL. Recent advances in the use of optical coherence tomography in neuro-ophthalmology: A review. Clin Exp Ophthalmol 2024; 52:220-233. [PMID: 38214066 DOI: 10.1111/ceo.14341] [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: 08/31/2023] [Revised: 11/26/2023] [Accepted: 11/28/2023] [Indexed: 01/13/2024]
Abstract
Optical coherence tomography (OCT) is an in vivo imaging modality that provides non-invasive, high resolution and fast cross-sectional images of the optic nerve head, retina and choroid. OCT angiography (OCTA) is an emerging tool. It is a non-invasive, dye-free imaging approach of visualising the microvasculature of the retina and choroid by employing motion contrast imaging for blood flow detection and is gradually receiving attention for its potential roles in various neuro-ophthalmic and retinal conditions. We will review the clinical utility of the OCT in the management of various common neuro-ophthalmic and neurological disorders. We also review some of the OCTA research findings in these conditions. Finally, we will discuss the limitations of OCT as well as introduce other emerging technologies.
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Affiliation(s)
- Jasmine Yaowei Ge
- Neuro-Ophthalmology Department, Singapore National Eye Centre, Singapore, Singapore
- Singapore Eye Research Institute, Singapore, Singapore
| | - Zhen Ling Teo
- Neuro-Ophthalmology Department, Singapore National Eye Centre, Singapore, Singapore
- Singapore Eye Research Institute, Singapore, Singapore
| | - Jing Liang Loo
- Neuro-Ophthalmology Department, Singapore National Eye Centre, Singapore, Singapore
- Singapore Eye Research Institute, Singapore, Singapore
- Duke NUS Medical School, Singapore, Singapore
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Zhang Y, Sun X, Tian G, Chen Y. Comparison of the clinical and genetic features of autosomal dominant optic atrophy and normal tension glaucoma in young Chinese adults. Eye (Lond) 2023; 37:624-630. [PMID: 35273349 PMCID: PMC9998393 DOI: 10.1038/s41433-022-01990-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 01/30/2022] [Accepted: 02/15/2022] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND/OBJECTIVES To compare the clinical and optical coherence tomography (OCT) characteristics of autosomal dominant optic atrophy (ADOA) and normal tension glaucoma (NTG) in Chinese patients. SUBJECTS/METHODS Twenty-four unrelated patients with ADOA and 21 unrelated patients with NTG, younger than 30 years, were enrolled in this study. Data regarding the demographic and clinical characteristics of the patients were collected, and their peripapillary retinal nerve fibre layer (RNFL) and macular ganglion cell complex (GCC) thicknesses were evaluated using OCT. Sequencing of genes associated with neuro-ophthalmic disorders was performed for all patients. RESULTS The average age at onset of the ADOA group (13.92 ± 10.73 years) was significantly younger than that of the NTG group (23.67 ± 4.98 years, P = 0.002). Best-corrected visual acuity was significantly poorer in the ADOA group (0.75 ± 0.32) than in the NTG group (0.16 ± 0.19, P < 0.001). The average peripapillary RNFL thickness and the RNFL thicknesses in the temporal upper, temporal lower, and nasal lower sectors were significantly thinner in the ADOA group than in the NTG group (all P < 0.05). Moreover, the macular GCC thickness of the ADOA group was significantly thinner than that of the NTG group (P < 0.001). Twenty-three OPA1 variants (11 novel OPA1 variants) and one OPA3 variant were detected in 24 patients with ADOA. CONCLUSIONS Our study revealed a distinct difference between the patterns of RNFL and GCC loss in ADOA and NTG, which will help to differentiate ADOA from NTG in young patients. Additionally, this study expanded the genetic spectrum of ADOA.
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Affiliation(s)
- Youjia Zhang
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Xinghuai Sun
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China
| | - Guohong Tian
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
| | - Yuhong Chen
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
- NHC Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China.
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OPA1 Dominant Optic Atrophy: Diagnostic Approach in the Pediatric Population. Curr Issues Mol Biol 2023; 45:465-478. [PMID: 36661516 PMCID: PMC9857649 DOI: 10.3390/cimb45010030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/29/2022] [Accepted: 01/01/2023] [Indexed: 01/07/2023] Open
Abstract
A clinical and genetic study was conducted with pediatric patients and their relatives with optic atrophy 1 (OPA1) mutations to establish whether there is a genotype-phenotype correlation among the variants detected within and between families. Eleven children with a confirmed OPA1 mutation were identified during the study period. The main initial complaint was reduced visual acuity (VA), present in eight patients of the cohort. Eight of eleven patients had a positive family history of optic atrophy. The mean visual acuity at the start of the study was 0.40 and 0.44 LogMAR in the right and left eye, respectively. At the end of the study, the mean visual acuity was unchanged. Optical coherence tomography during the first visit showed a mean retinal nerve fiber layer thickness of 81.6 microns and 80.5 microns in the right and left eye, respectively; a mean ganglion cell layer of 52.5 and 52.4 microns, respectively, and a mean central macular thickness of 229.5 and 233.5 microns, respectively. The most common visual field defect was a centrocecal scotoma, and nine out of eleven patients showed bilateral temporal disc pallor at baseline. Sequencing of OPA1 showed seven different mutations in the eleven patients, one of which, NM_130837.3: c.1406_1407del (p.Thr469LysfsTer16), has not been previously reported. Early diagnosis of dominant optic atrophy is crucial, both for avoiding unnecessary consultations and/or treatments and for appropriate genetic counseling.
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Evaluation of optical coherence tomography findings and visual evoked potentials in Charcot-Marie-Tooth disease. Int Ophthalmol 2023; 43:333-341. [PMID: 35953577 DOI: 10.1007/s10792-022-02452-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 07/31/2022] [Indexed: 02/07/2023]
Abstract
PURPOSE To evaluate the spectral-domain optical coherence tomography (SD-OCT) findings and pattern visual evoked potential (VEP) in Charcot-Marie-Tooth (CMT) disease. METHODS Seventeen patients with CMT disease and 17 control subjects were included in the study. The patients were divided into two groups according to conduction velocity and inheritance pattern as demyelinating type (CMT 1) and axonal type (CMT 2). The average retinal nerve fiber layer (RNFL) thickness, RNFL thicknesses of all quadrants, and thicknesses of the ganglion cell layer complex (GCC) were measured using SD-OCT. Pattern VEP recordings were evaluated in both groups. RESULTS The average and four quadrants of RNFL thicknesses, and superior and inferior GCC thicknesses were significantly thinner in the CMT patients compared with healthy individuals, but there were no statistically significant differences between the CMT groups. There was a significant positive correlation between age and all RNFL and GCC thicknesses in the CMT 2 group and between age and RNFL thickness of the temporal quadrant in the CMT 1 group. P100 latencies were significantly delayed in the CMT groups compared with controls, and there were no significant differences in P100 latencies between the CMT groups (p < 0.001). VEP amplitudes were in normal ranges in the CMT groups. CONCLUSION This study showed that RNFL and GCC thicknesses were significantly reduced and VEP latencies were prolonged in patients with CMT with normal clinical examinations. Our results suggest that optic nerves may be affected more frequently in patients with CMT that is detected in clinical examinations.
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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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Pathophysiological Heterogeneity of the BBSOA Neurodevelopmental Syndrome. Cells 2022; 11:cells11081260. [PMID: 35455940 PMCID: PMC9024734 DOI: 10.3390/cells11081260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 03/17/2022] [Accepted: 03/29/2022] [Indexed: 11/17/2022] Open
Abstract
The formation and maturation of the human brain is regulated by highly coordinated developmental events, such as neural cell proliferation, migration and differentiation. Any impairment of these interconnected multi-factorial processes can affect brain structure and function and lead to distinctive neurodevelopmental disorders. Here, we review the pathophysiology of the Bosch–Boonstra–Schaaf Optic Atrophy Syndrome (BBSOAS; OMIM 615722; ORPHA 401777), a recently described monogenic neurodevelopmental syndrome caused by the haploinsufficiency of NR2F1 gene, a key transcriptional regulator of brain development. Although intellectual disability, developmental delay and visual impairment are arguably the most common symptoms affecting BBSOAS patients, multiple additional features are often reported, including epilepsy, autistic traits and hypotonia. The presence of specific symptoms and their variable level of severity might depend on still poorly characterized genotype–phenotype correlations. We begin with an overview of the several mutations of NR2F1 identified to date, then further focuses on the main pathological features of BBSOAS patients, providing evidence—whenever possible—for the existing genotype–phenotype correlations. On the clinical side, we lay out an up-to-date list of clinical examinations and therapeutic interventions recommended for children with BBSOAS. On the experimental side, we describe state-of-the-art in vivo and in vitro studies aiming at deciphering the role of mouse Nr2f1, in physiological conditions and in pathological contexts, underlying the BBSOAS features. Furthermore, by modeling distinct NR2F1 genetic alterations in terms of dimer formation and nuclear receptor binding efficiencies, we attempt to estimate the total amounts of functional NR2F1 acting in developing brain cells in normal and pathological conditions. Finally, using the NR2F1 gene and BBSOAS as a paradigm of monogenic rare neurodevelopmental disorder, we aim to set the path for future explorations of causative links between impaired brain development and the appearance of symptoms in human neurological syndromes.
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Sladen PE, Perdigão PR, Salsbury G, Novoselova T, van der Spuy J, Chapple JP, Yu-Wai-Man P, Cheetham ME. CRISPR-Cas9 correction of OPA1 c.1334G>A: p.R445H restores mitochondrial homeostasis in dominant optic atrophy patient-derived iPSCs. MOLECULAR THERAPY. NUCLEIC ACIDS 2021; 26:432-443. [PMID: 34589289 PMCID: PMC8455316 DOI: 10.1016/j.omtn.2021.08.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 08/09/2021] [Indexed: 12/26/2022]
Abstract
Autosomal dominant optic atrophy (DOA) is the most common inherited optic neuropathy in the United Kingdom. DOA has an insidious onset in early childhood, typically presenting with bilateral, central visual loss caused by the preferential loss of retinal ganglion cells. 60%-70% of genetically confirmed DOA cases are associated with variants in OPA1, a ubiquitously expressed GTPase that regulates mitochondrial homeostasis through coordination of inner membrane fusion, maintenance of cristae structure, and regulation of bioenergetic output. Whether genetic correction of OPA1 pathogenic variants can alleviate disease-associated phenotypes remains unknown. Here, we demonstrate generation of patient-derived OPA1 c.1334G>A: p.R445H mutant induced pluripotent stem cells (iPSCs), followed by correction of OPA1 through CRISPR-Cas9-guided homology-directed repair (HDR) and evaluate the effect of OPA1 correction on mitochondrial homeostasis. CRISPR-Cas9 gene editing demonstrated an efficient method of OPA1 correction, with successful gene correction in 57% of isolated iPSCs. Correction of OPA1 restored mitochondrial homeostasis, re-establishing the mitochondrial network and basal respiration and ATP production levels. In addition, correction of OPA1 re-established the levels of wild-type (WT) mitochondrial DNA (mtDNA) and reduced susceptibility to apoptotic stimuli. These data demonstrate that nuclear gene correction can restore mitochondrial homeostasis and improve mtDNA integrity in DOA patient-derived cells carrying an OPA1 variant.
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Affiliation(s)
- Paul E. Sladen
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | | | - Grace Salsbury
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UK
| | - Tatiana Novoselova
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UK
| | | | - J. Paul Chapple
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UK
| | - Patrick Yu-Wai-Man
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
- Cambridge Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, ED Adrian Building, Robinson Way, Cambridge CB2 0PY, UK
- John van Geest Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0PY, UK
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Jurkute N, Bertacchi M, Arno G, Tocco C, Kim US, Kruszewski AM, Avery RA, Bedoukian EC, Han J, Ahn SJ, Pontikos N, Acheson J, Davagnanam I, Bowman R, Kaliakatsos M, Gardham A, Wakeling E, Oluonye N, Reddy MA, Clark E, Rosser E, Amati-Bonneau P, Charif M, Lenaers G, Meunier I, Defoort S, Vincent-Delorme C, Robson AG, Holder GE, Jeanjean L, Martinez-Monseny A, Vidal-Santacana M, Dominici C, Gaggioli C, Giordano N, Caleo M, Liu GT, Webster AR, Studer M, Yu-Wai-Man P. Pathogenic NR2F1 variants cause a developmental ocular phenotype recapitulated in a mutant mouse model. Brain Commun 2021; 3:fcab162. [PMID: 34466801 PMCID: PMC8397830 DOI: 10.1093/braincomms/fcab162] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/10/2021] [Indexed: 11/28/2022] Open
Abstract
Pathogenic NR2F1 variants cause a rare autosomal dominant neurodevelopmental disorder referred to as the Bosch-Boonstra-Schaaf Optic Atrophy Syndrome. Although visual loss is a prominent feature seen in affected individuals, the molecular and cellular mechanisms contributing to visual impairment are still poorly characterized. We conducted a deep phenotyping study on a cohort of 22 individuals carrying pathogenic NR2F1 variants to document the neurodevelopmental and ophthalmological manifestations, in particular the structural and functional changes within the retina and the optic nerve, which have not been detailed previously. The visual impairment became apparent in early childhood with small and/or tilted hypoplastic optic nerves observed in 10 cases. High-resolution optical coherence tomography imaging confirmed significant loss of retinal ganglion cells with thinning of the ganglion cell layer, consistent with electrophysiological evidence of retinal ganglion cells dysfunction. Interestingly, for those individuals with available longitudinal ophthalmological data, there was no significant deterioration in visual function during the period of follow-up. Diffusion tensor imaging tractography studies showed defective connections and disorganization of the extracortical visual pathways. To further investigate how pathogenic NR2F1 variants impact on retinal and optic nerve development, we took advantage of an Nr2f1 mutant mouse disease model. Abnormal retinogenesis in early stages of development was observed in Nr2f1 mutant mice with decreased retinal ganglion cell density and disruption of retinal ganglion cell axonal guidance from the neural retina into the optic stalk, accounting for the development of optic nerve hypoplasia. The mutant mice showed significantly reduced visual acuity based on electrophysiological parameters with marked conduction delay and decreased amplitude of the recordings in the superficial layers of the visual cortex. The clinical observations in our study cohort, supported by the mouse data, suggest an early neurodevelopmental origin for the retinal and optic nerve head defects caused by NR2F1 pathogenic variants, resulting in congenital vision loss that seems to be non-progressive. We propose NR2F1 as a major gene that orchestrates early retinal and optic nerve head development, playing a key role in the maturation of the visual system.
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Affiliation(s)
- Neringa Jurkute
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
- Institute of Ophthalmology, University College London, London, UK
| | | | - Gavin Arno
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
- Institute of Ophthalmology, University College London, London, UK
| | - Chiara Tocco
- Université Côte d’Azur, CNRS, Inserm, iBV, Nice, France
| | - Ungsoo Samuel Kim
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
- Kim's Eye Hospital, Seoul, South Korea
| | - Adam M Kruszewski
- Department of Neurology, Hospital of the University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - Robert A Avery
- Division of Ophthalmology, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Neurology, Perelman School of Medicine, Philadelphia, PA, USA
- Department of Ophthalmology, Perelman School of Medicine, Philadelphia, PA, USA
| | - Emma C Bedoukian
- Roberts Individualized Medical Genetics Center, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - Jinu Han
- Institute of Vision Research, Department of Ophthalmology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Sung Jun Ahn
- Department of Radiology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Nikolas Pontikos
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
- Institute of Ophthalmology, University College London, London, UK
| | - James Acheson
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
- National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Trust, London, UK
| | - Indran Davagnanam
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
- Department of Brain Repair & Rehabilitation, UCL Queen Square Institute of Neurology, London, UK
| | - Richard Bowman
- Department of Ophthalmology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Marios Kaliakatsos
- Paediatric Neurology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Alice Gardham
- North West Thames Regional Genetics Service, Northwick Park Hospital, Harrow, UK
| | - Emma Wakeling
- North East Thames Regional Genetics Service, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Ngozi Oluonye
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
- Wolfson Neurodisability Service, Great Ormond Street Hospital NHS Foundation Trust, London, UK
| | - Maddy Ashwin Reddy
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
- Royal London Hospital, Barts Health NHS Trust, London, UK
| | - Elaine Clark
- Department of Neuroscience, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Elisabeth Rosser
- Department of Clinical Genetics, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Patrizia Amati-Bonneau
- MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, Angers University and Hospital, Angers, France
- Department of Biochemistry and Genetics, University Hospital Angers, Angers, France
- Genetics and Immuno-cell Therapy Team, Mohammed First University, Oujda, Morocco
| | - Majida Charif
- MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, Angers University and Hospital, Angers, France
- National Center for Rare Diseases, Inherited Sensory Disorders, Gui de Chauliac Hospital, Montpellier, France
| | - Guy Lenaers
- MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, Angers University and Hospital, Angers, France
| | - Isabelle Meunier
- Institut des Neurosciences de Montpellier, INSERM INSERM U1051, Université de Montpellier, Montpellier, France
| | - Sabine Defoort
- Service d'exploration de la vision et neuro-ophtalmologie, CHRU de Lille, Lille, France
| | | | - Anthony G Robson
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
- Institute of Ophthalmology, University College London, London, UK
| | - Graham E Holder
- Institute of Ophthalmology, University College London, London, UK
- Yong Loo Lin School of Medicine, Department of Ophthalmology, National University of Singapore, Singapore, Singapore
| | - Luc Jeanjean
- Department of Ophthalmology, University Hospital of Nimes, Nimes, France
| | | | | | - Chloé Dominici
- University Côte d'Azur, CNRS UMR7284, INSERM U1081, Institute for Research on Cancer and Aging, Nice, France
| | - Cedric Gaggioli
- University Côte d'Azur, CNRS UMR7284, INSERM U1081, Institute for Research on Cancer and Aging, Nice, France
| | | | | | - Grant T Liu
- Division of Ophthalmology, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Neurology, Perelman School of Medicine, Philadelphia, PA, USA
- Department of Ophthalmology, Perelman School of Medicine, Philadelphia, PA, USA
| | | | - Andrew R Webster
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
- Institute of Ophthalmology, University College London, London, UK
| | | | - Patrick Yu-Wai-Man
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
- Institute of Ophthalmology, University College London, London, UK
- Cambridge Eye Unit, Addenbrooke’s Hospital, Cambridge University Hospitals, Cambridge, UK
- John van Geest Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
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12
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Lenaers G, Neutzner A, Le Dantec Y, Jüschke C, Xiao T, Decembrini S, Swirski S, Kieninger S, Agca C, Kim US, Reynier P, Yu-Wai-Man P, Neidhardt J, Wissinger B. Dominant optic atrophy: Culprit mitochondria in the optic nerve. Prog Retin Eye Res 2021; 83:100935. [PMID: 33340656 DOI: 10.1016/j.preteyeres.2020.100935] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 12/05/2020] [Accepted: 12/09/2020] [Indexed: 12/14/2022]
Abstract
Dominant optic atrophy (DOA) is an inherited mitochondrial disease leading to specific degeneration of retinal ganglion cells (RGCs), thus compromising transmission of visual information from the retina to the brain. Usually, DOA starts during childhood and evolves to poor vision or legal blindness, affecting the central vision, whilst sparing the peripheral visual field. In 20% of cases, DOA presents as syndromic disorder, with secondary symptoms affecting neuronal and muscular functions. Twenty years ago, we demonstrated that heterozygous mutations in OPA1 are the most frequent molecular cause of DOA. Since then, variants in additional genes, whose functions in many instances converge with those of OPA1, have been identified by next generation sequencing. OPA1 encodes a dynamin-related GTPase imported into mitochondria and located to the inner membrane and intermembrane space. The many OPA1 isoforms, resulting from alternative splicing of three exons, form complex homopolymers that structure mitochondrial cristae, and contribute to fusion of the outer membrane, thus shaping the whole mitochondrial network. Moreover, OPA1 is required for oxidative phosphorylation, maintenance of mitochondrial genome, calcium homeostasis and regulation of apoptosis, thus making OPA1 the Swiss army-knife of mitochondria. Understanding DOA pathophysiology requires the understanding of RGC peculiarities with respect to OPA1 functions. Besides the tremendous energy requirements of RGCs to relay visual information from the eye to the brain, these neurons present unique features related to their differential environments in the retina, and to the anatomical transition occurring at the lamina cribrosa, which parallel major adaptations of mitochondrial physiology and shape, in the pre- and post-laminar segments of the optic nerve. Three DOA mouse models, with different Opa1 mutations, have been generated to study intrinsic mechanisms responsible for RGC degeneration, and these have further revealed secondary symptoms related to mitochondrial dysfunctions, mirroring the more severe syndromic phenotypes seen in a subgroup of patients. Metabolomics analyses of cells, mouse organs and patient plasma mutated for OPA1 revealed new unexpected pathophysiological mechanisms related to mitochondrial dysfunction, and biomarkers correlated quantitatively to the severity of the disease. Here, we review and synthesize these data, and propose different approaches for embracing possible therapies to fulfil the unmet clinical needs of this disease, and provide hope to affected DOA patients.
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Affiliation(s)
- Guy Lenaers
- MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, Angers University and Hospital, Angers, France.
| | - Albert Neutzner
- Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland; Department of Ophthalmology University Hospital Basel, University of Basel, Basel, Switzerland.
| | - Yannick Le Dantec
- MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, Angers University and Hospital, Angers, France
| | - Christoph Jüschke
- Human Genetics, Faculty VI - School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany
| | - Ting Xiao
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Sarah Decembrini
- Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland; Department of Ophthalmology University Hospital Basel, University of Basel, Basel, Switzerland
| | - Sebastian Swirski
- Human Genetics, Faculty VI - School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany
| | - Sinja Kieninger
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Cavit Agca
- Molecular Biology, Genetics and Bioengineering Program, Sabanci University, Istanbul, Turkey; Nanotechnology Research and Application Center (SUNUM), Sabanci University, Istanbul, Turkey
| | - Ungsoo S Kim
- Kim's Eye Hospital, Seoul, South Korea; Cambridge Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Cambridge Eye Unit, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, UK; Moorfields Eye Hospital, London, UK
| | - Pascal Reynier
- MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, Angers University and Hospital, Angers, France; Department of Biochemistry, University Hospital of Angers, Angers, France
| | - Patrick Yu-Wai-Man
- Cambridge Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Cambridge Eye Unit, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, UK; Moorfields Eye Hospital, London, UK; UCL Institute of Ophthalmology, University College London, London, UK
| | - John Neidhardt
- Human Genetics, Faculty VI - School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany; Research Center Neurosensory Science, University Oldenburg, Oldenburg, Germany.
| | - Bernd Wissinger
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Tübingen, Germany.
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13
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Abri Aghdam K, Aghajani A, Razi-Khosroshahi M, Soltan Sanjari M, Chaibakhsh S, Falavarjani KG. Optical Coherence Tomography Angiography and Structural Analyses of the Pale Optic Discs: Is It Possible to Differentiate the Cause? Curr Eye Res 2021; 46:1876-1885. [PMID: 33980086 DOI: 10.1080/02713683.2021.1929331] [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
Introduction: To compare the optic nerve head (ONH) structure and microvasculature in patients with optic atrophy due to non-arteritic anterior ischemic optic neuropathy (NAION), compressive optic neuropathy (CON), methanol-induced optic neuropathy (MION), and traumatic optic neuropathy (TON) using optical coherence tomography angiography.Methods: In this comparative, cross-sectional study, 32 eyes with NAION, 18 eyes with CON, 32 eyes with MION, 23 eyes with TON, and 55 normal eyes were enrolled. Radial peripapillary capillary (RPC) vessel density, peripapillary retinal nerve fiber layer (RNFL) thickness, disc area, cup volume, and cup/disc area ratio were obtained using the RTVue XR Avanti system (Optovue Inc., Fremont, CA, USA).Results: RPC vessel density and peripapillary RNFL thickness in all patients were significantly lower than normal subjects. A positive correlation was found between the RPC vessel density and peripapillary RNFL thickness in normal subjects and all study groups. The positive correlation between the inside and outside disc RPC vessel density was only found in the NAION (r = 0.36, P = .042) and MION (r = 0.42, P = .018) groups. No significant difference was found among the groups in terms of peripapillary and inside disc vascular densities (all P > .05). Disc area and cup volume in patients with MION was larger than the values in patients with NAION (P = .018) and TON (P = .044) and normal subjects (P = .015). The discriminating features among the study groups were the larger cup volume and cup/disc area ratio in patients with MION, and lower RNFL thickness in patients with TON.Conclusions: There was a positive correlation between the RNFL thickness and peripapillary RPC vessel density regardless of the cause of optic disc pallor. Structural evaluation of the ONH seems to be a better way to differentiate the cause of optic nerve head atrophy than the microangiographic changes.
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Affiliation(s)
- Kaveh Abri Aghdam
- Eye Research Center, The Five Senses Institute, Rassoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
| | - Ali Aghajani
- Eye Research Center, The Five Senses Institute, Rassoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
| | - Marjan Razi-Khosroshahi
- Eye Research Center, The Five Senses Institute, Rassoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
| | - Mostafa Soltan Sanjari
- Eye Research Center, The Five Senses Institute, Rassoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
| | - Samira Chaibakhsh
- Eye Research Center, The Five Senses Institute, Rassoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
| | - Khalil Ghasemi Falavarjani
- Eye Research Center, The Five Senses Institute, Rassoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran.,Stem Cell and Regenerative Medicine Research Center, Iran University of Medical Sciences, Tehran, Iran
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14
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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.
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15
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Amore G, Romagnoli M, Carbonelli M, Barboni P, Carelli V, La Morgia C. Therapeutic Options in Hereditary Optic Neuropathies. Drugs 2021; 81:57-86. [PMID: 33159657 PMCID: PMC7843467 DOI: 10.1007/s40265-020-01428-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Options for the effective treatment of hereditary optic neuropathies have been a long time coming. The successful launch of the antioxidant idebenone for Leber's Hereditary Optic Neuropathy (LHON), followed by its introduction into clinical practice across Europe, was an important step forward. Nevertheless, other options, especially for a variety of mitochondrial optic neuropathies such as dominant optic atrophy (DOA), are needed, and a number of pharmaceutical agents, acting on different molecular pathways, are currently under development. These include gene therapy, which has reached Phase III development for LHON, but is expected to be developed also for DOA, whilst most of the other agents (other antioxidants, anti-apoptotic drugs, activators of mitobiogenesis, etc.) are almost all at Phase II or at preclinical stage of research. Here, we review proposed target mechanisms, preclinical evidence, available clinical trials with primary endpoints and results, of a wide range of tested molecules, to give an overview of the field, also providing the landscape of future scenarios, including gene therapy, gene editing, and reproductive options to prevent transmission of mitochondrial DNA mutations.
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Affiliation(s)
- Giulia Amore
- Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy
| | - Martina Romagnoli
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Via Altura 3, 40139, Bologna, Italy
| | - Michele Carbonelli
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Via Altura 3, 40139, Bologna, Italy
| | | | - Valerio Carelli
- Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Via Altura 3, 40139, Bologna, Italy
| | - Chiara La Morgia
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Via Altura 3, 40139, Bologna, Italy.
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16
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Freude KK, Saruhanian S, McCauley A, Paterson C, Odette M, Oostenink A, Hyttel P, Gillies M, Haukedal H, Kolko M. Enrichment of retinal ganglion and Müller glia progenitors from retinal organoids derived from human induced pluripotent stem cells - possibilities and current limitations. World J Stem Cells 2020; 12:1171-1183. [PMID: 33178399 PMCID: PMC7596448 DOI: 10.4252/wjsc.v12.i10.1171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 07/03/2020] [Accepted: 08/16/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Retinal organoids serve as excellent human-specific disease models for conditions affecting otherwise inaccessible retinal tissue from patients. They permit the isolation of key cell types affected in various eye diseases including retinal ganglion cells (RGCs) and Müller glia.
AIM To refine human-induced pluripotent stem cells (hiPSCs) differentiated into three-dimensional (3D) retinal organoids to generate sufficient numbers of RGCs and Müller glia progenitors for downstream analyses.
METHODS In this study we described, evaluated, and refined methods with which to generate Müller glia and RGC progenitors, isolated them via magnetic-activated cell sorting, and assessed their lineage stability after prolonged 2D culture. Putative progenitor populations were characterized via quantitative PCR and immunocytochemistry, and the ultrastructural composition of retinal organoid cells was investigated.
RESULTS Our study confirms the feasibility of generating marker-characterized Müller glia and RGC progenitors within retinal organoids. Such retinal organoids can be dissociated and the Müller glia and RGC progenitor-like cells isolated via magnetic-activated cell sorting and propagated as monolayers.
CONCLUSION Enrichment of Müller glia and RGC progenitors from retinal organoids is a feasible method with which to study cell type-specific disease phenotypes and to potentially generate specific retinal populations for cell replacement therapies.
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Affiliation(s)
- Kristine Karla Freude
- Department of Veterinary and Animal Sciences, Group of Stem Cell Models for Studies of Neurodegenerative Diseases, Section for Pathobiological Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg 1870, Denmark
| | - Sarkis Saruhanian
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen 2100, Denmark
| | - Alanna McCauley
- Department of Veterinary and Animal Sciences, Group of Stem Cell Models for Studies of Neurodegenerative Diseases, Section for Pathobiological Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg 1870, Denmark
| | - Colton Paterson
- Department of Veterinary and Animal Sciences, Group of Stem Cell Models for Studies of Neurodegenerative Diseases, Section for Pathobiological Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg 1870, Denmark
| | - Madeleine Odette
- Department of Veterinary and Animal Sciences, Group of Stem Cell Models for Studies of Neurodegenerative Diseases, Section for Pathobiological Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg 1870, Denmark
| | - Annika Oostenink
- Department of Veterinary and Animal Sciences, Group of Stem Cell Models for Studies of Neurodegenerative Diseases, Section for Pathobiological Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg 1870, Denmark
| | - Poul Hyttel
- Department of Veterinary and Animal Sciences, Group of Stem Cell Models for Studies of Neurodegenerative Diseases, Section for Pathobiological Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg 1870, Denmark
| | - Mark Gillies
- Save Sight Institute, South Block, Sydney Eye Hospital, Sydney 2000, Australia
| | - Henriette Haukedal
- Department of Veterinary and Animal Sciences, Group of Stem Cell Models for Studies of Neurodegenerative Diseases, Section for Pathobiological Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg 1870, Denmark
| | - Miriam Kolko
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen 2100, Denmark
- Department of Ophthalmology, Copenhagen University Hospital, Rigshospitalet-Glostrup, Glostrup 2600, Denmark
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17
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Zeng T, Liao L, Guo Y, Liu X, Xiong X, Zhang Y, Cen S, Li H, Wei S. Concurrent OPA1 mutation and chromosome 3q deletion leading to Behr syndrome: a case report. BMC Pediatr 2020; 20:420. [PMID: 32883255 PMCID: PMC7469303 DOI: 10.1186/s12887-020-02309-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 08/20/2020] [Indexed: 12/02/2022] Open
Abstract
Background Optic atrophy 1 (OPA1) gene mutations are associated with dominantly inherited optic neuropathy resulting in a progressive loss of visual acuity. Compound heterozygous or homozygous variants that lead to severe phenotypes, including Behr syndrome, have been reported rarely. Case presentation Here, we present a 14-month-old boy with early onset optic atrophy, congenital cataracts, neuromuscular disorders, mental retardation, and developmental delay. Combined genetic testing, including whole exome sequencing (WES) and chromosomal microarray analysis, revealed a concurrent OPA1 variant (c.2189 T > C p.Leu730Ser) and de novo chromosome 3q deletion as pathogenic variants leading to the severe phenotype. Conclusions Our case is the first reporting a novel missense OPA1 variant co-occurring with a chromosomal microdeletion leading to a severe phenotype reminiscent of Behr syndrome. This expands the mutation spectrum of OPA1 and inheritance patterns of this disease.
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Affiliation(s)
- Ting Zeng
- Department of Child Healthcare, Liuzhou Maternity and Child Healthcare Hospital, 50 Boyuan Avenue, Liuzhou, 545616, China.,Key Laboratory of Developmental Disorders in Children, Liuzhou Maternity and Child Healthcare Hospital, 50 Boyuan Avenue, Liuzhou, 545616, China
| | - Linyan Liao
- Department of Child Healthcare, Liuzhou Maternity and Child Healthcare Hospital, 50 Boyuan Avenue, Liuzhou, 545616, China
| | - Yi Guo
- Department of Child Healthcare, Liuzhou Maternity and Child Healthcare Hospital, 50 Boyuan Avenue, Liuzhou, 545616, China
| | - Xuxu Liu
- Department of Child Healthcare, Liuzhou Maternity and Child Healthcare Hospital, 50 Boyuan Avenue, Liuzhou, 545616, China
| | - Xiaobo Xiong
- Department of Child Healthcare, Liuzhou Maternity and Child Healthcare Hospital, 50 Boyuan Avenue, Liuzhou, 545616, China
| | - Yu Zhang
- Department of Child Healthcare, Liuzhou Maternity and Child Healthcare Hospital, 50 Boyuan Avenue, Liuzhou, 545616, China.,Key Laboratory of Developmental Disorders in Children, Liuzhou Maternity and Child Healthcare Hospital, 50 Boyuan Avenue, Liuzhou, 545616, China
| | - Shi Cen
- Department of Child Healthcare, Liuzhou Maternity and Child Healthcare Hospital, 50 Boyuan Avenue, Liuzhou, 545616, China.,Key Laboratory of Developmental Disorders in Children, Liuzhou Maternity and Child Healthcare Hospital, 50 Boyuan Avenue, Liuzhou, 545616, China
| | - Honghui Li
- Department of Child Healthcare, Liuzhou Maternity and Child Healthcare Hospital, 50 Boyuan Avenue, Liuzhou, 545616, China.,Key Laboratory of Developmental Disorders in Children, Liuzhou Maternity and Child Healthcare Hospital, 50 Boyuan Avenue, Liuzhou, 545616, China
| | - Shuzhang Wei
- Department of Child Healthcare, Liuzhou Maternity and Child Healthcare Hospital, 50 Boyuan Avenue, Liuzhou, 545616, China. .,Key Laboratory of Developmental Disorders in Children, Liuzhou Maternity and Child Healthcare Hospital, 50 Boyuan Avenue, Liuzhou, 545616, China.
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18
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Jurkute N, Majander A, Bowman R, Votruba M, Abbs S, Acheson J, Lenaers G, Amati-Bonneau P, Moosajee M, Arno G, Yu-Wai-Man P. Clinical utility gene card for: inherited optic neuropathies including next-generation sequencing-based approaches. Eur J Hum Genet 2018; 27:494-502. [PMID: 30143805 DOI: 10.1038/s41431-018-0235-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 06/14/2018] [Accepted: 07/17/2018] [Indexed: 01/14/2023] Open
Affiliation(s)
- Neringa Jurkute
- NIHR Biomedical Research Centre at Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, UK
| | - Anna Majander
- Department of Ophthalmology, Helsinki University Hospital, University of Helsinki, Helsinki, Finland
| | - Richard Bowman
- Department of Ophthalmology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Marcela Votruba
- School of Optometry and Vision Sciences, Cardiff University, and Cardiff Eye Unit, University Hospital Wales, Cardiff, UK
| | - Stephen Abbs
- Department of Clinical Genetics, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - James Acheson
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Guy Lenaers
- PREMMi/Mitochondrial Medicine Research Centre, Institut MITOVASC, CNRS UMR 6015, INSERM U1083, Université d'Angers, CHU d'Angers, Angers, France
| | - Patrizia Amati-Bonneau
- PREMMi/Mitochondrial Medicine Research Centre, Institut MITOVASC, CNRS UMR 6015, INSERM U1083, Université d'Angers, CHU d'Angers, Angers, France.,Department of Biochemistry and Genetics, UMR CNRS 6015-INSERM U1083, CHU Angers, Angers, France
| | - Mariya Moosajee
- Department of Ophthalmology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK.,Institute of Ophthalmology, University College London, London, UK
| | - Gavin Arno
- Moorfields Eye Hospital NHS Foundation Trust, London, UK.,Institute of Ophthalmology, University College London, London, UK
| | - Patrick Yu-Wai-Man
- NIHR Biomedical Research Centre at Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, UK. .,Newcastle Eye Centre, Royal Victoria Infirmary, Newcastle upon Tyne, UK. .,Cambridge Eye Unit, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, UK. .,Cambridge Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
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19
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Corajevic N, Larsen M, Rönnbäck C. Thickness mapping of individual retinal layers and sectors by Spectralis SD-OCT in Autosomal Dominant Optic Atrophy. Acta Ophthalmol 2018; 96:251-256. [PMID: 29091347 DOI: 10.1111/aos.13588] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Accepted: 08/11/2017] [Indexed: 01/06/2023]
Abstract
PURPOSE To assess layer- and location-specific retinal thickness deficits in autosomal dominant optic atrophy (ADOA) using Spectralis SD-OCT. METHODS This cross-sectional study included 41 ADOA patients with OPA1 exon 28 (2826delT) mutation [age, 8.6-83.5 years; best-corrected visual acuity (BCVA), 8-89 Early Treatment Diabetic Retinopathy Study (ETDRS) letters] and 55 mutation-free first-degree relatives as healthy controls (age, 8.9-68.7; BCVA, 80-99). Participants underwent routine examination and optical coherence tomography (OCT) with segmentation of the whole retina, inner retinal layers (IRL) and outer retinal layers (ORL). Individual segmentation was performed of the perifoveal retinal nerve fibre layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), retinal pigment epithelium (RPE) and the peripapillary RNFL. Combinations of layers and sectors were tested for their diagnostic significance. Only right eye data are presented. Statistical analysis was adjusted for age, gender, spherical equivalent, axial length and family clustering in a mixed model analysis. RESULTS The perifoveal RNFL, GCL, IPL and the peripapillary RNFL were all significantly thinner in ADOA patients than in healthy controls (p < 0.0001). No statistical difference was found for other layers. The most prominent and diagnostically most valuable deficit was found in the GCL (-49.9%) in the 'nasal inner macula' (NIM) sector (-63%). Attenuation of the peripapillary RNFL was most significant in the temporal sector (-58.4%). CONCLUSION In ADOA, retinal ganglion cells are most prominently reduced in the nasal perifoveal area of the GCL, which together with the temporal peripapillary RNFL area serves as the strongest diagnostic OCT marker.
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Affiliation(s)
- Nihada Corajevic
- Department of Ophthalmology; Glostrup Hospital; Copenhagen Denmark
| | - Michael Larsen
- Department of Ophthalmology; Glostrup Hospital; Copenhagen Denmark
| | - Cecilia Rönnbäck
- Department of Ophthalmology; Glostrup Hospital; Copenhagen Denmark
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Characterization of Charcot-Marie-Tooth optic neuropathy. J Neurol 2017; 264:2431-2435. [PMID: 29063243 DOI: 10.1007/s00415-017-8645-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 10/10/2017] [Accepted: 10/11/2017] [Indexed: 10/18/2022]
Abstract
Varying degrees of optic neuropathy can be seen in patients with Charcot-Marie-Tooth (CMT) disease. To define and characterize the extent of optic neuropathy in patients with CMT2A and CMT1A, two patients from both sub-classifications were evaluated. All patients underwent complete neuro-ophthalmic examinations, and optical coherence (OCT) measurements of the retinal nerve fiber layer (RNFL) and ganglion cell layer complex (GCC) were obtained, along with pattern visual evoked potential (VEP) and pattern electroretinogram (ERG) recordings. RNFL thickness measurements were decreased in both patients with CMT2A, and normal in both patients with CMT1A. GCC measurements were decreased in both patients with CMT2A, mildly decreased in one patient with CMT1A and normal in the second CMT1A patient. VEP latencies were delayed in one patient with CMT2A and one patient with CMT1A. VEP latencies were immeasurable in the other CMT2A patient and not obtained in the second CMT1A patient. Pattern ERG P50-N95 amplitudes were decreased in both patients with CMT2A and normal in one patient with CMT1A. The pattern ERG was immeasurable in the second patient with CMT1A. The pattern of RNFL and GCC thinning in CMT2A with optic neuropathy, a subset of HMSN VI, closely resembles that seen in other mitochondrial optic neuropathies.
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Gaier ED, Boudreault K, Nakata I, Janessian M, Skidd P, DelBono E, Allen KF, Pasquale LR, Place E, Cestari DM, Stacy RC, Rizzo JF, Wiggs JL. Diagnostic genetic testing for patients with bilateral optic neuropathy and comparison of clinical features according to OPA1 mutation status. Mol Vis 2017; 23:548-560. [PMID: 28848318 PMCID: PMC5561143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Accepted: 08/08/2017] [Indexed: 10/26/2022] Open
Abstract
PURPOSE Inherited optic neuropathy is genetically heterogeneous, and genetic testing has an important role in risk assessment and counseling. The purpose of this study is to determine the prevalence and spectrum of mutations in a group of patients referred for genetic testing to a tertiary center in the United States. In addition, we compared the clinical features of patients with and without mutations in OPA1, the gene most commonly involved in dominantly inherited optic atrophy. METHODS Clinical data and genetic testing results were reviewed for 74 unrelated, consecutive patients referred with a history of insidious, relatively symmetric, bilateral visual loss secondary to an optic neuropathy. Patients were evaluated for disease-causing variants in OPA1, OPA3, WFS1, and the entire mitochondrial genome with DNA sequencing and copy number variation (CNV) testing. RESULTS Pathogenic DNA variants were found in 25 cases, with the majority (24 patients) located in OPA1. Demographics, clinical history, and clinical features for the group of patients with mutations in OPA1 were compared to those without disease-causing variants. Compared to the patients without mutations, cases with mutations in OPA1 were more likely to have a family history of optic nerve disease (p = 0.027); however, 30.4% of patients without a family history of disease also had mutations in OPA1. OPA1 mutation carriers had less severe mean deviation and pattern standard deviation on automated visual field testing than patients with optic atrophy without mutations in OPA1 (p<0.005). Other demographic and ocular features were not statistically significantly different between the two groups, including the fraction of patients with central scotomas (42.9% of OPA1 mutation positive and 66.0% of OPA1 mutation negative). CONCLUSIONS Genetic testing identified disease-causing mutations in 34% of referred cases, with the majority of these in OPA1. Patients with mutations in OPA1 were more likely to have a family history of disease; however, 30.4% of patients without a family history were also found to have an OPA1 mutation. This observation, as well as similar frequencies of central scotomas in the groups with and without mutations in OPA1, underscores the need for genetic testing to establish an OPA1 genetic diagnosis.
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Affiliation(s)
- Eric D. Gaier
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary Boston, MA
| | - Katherine Boudreault
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary Boston, MA
| | - Isao Nakata
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary Boston, MA
| | - Maria Janessian
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary Boston, MA
| | - Philip Skidd
- Departments of Ophthalmology and Neurology, University of Vermont College of Medicine, Burlington, MA
| | - Elizabeth DelBono
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary Boston, MA
| | - Keri F. Allen
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary Boston, MA
| | - Louis R. Pasquale
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary Boston, MA,Channing Division of Network Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Emily Place
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary Boston, MA
| | - Dean M. Cestari
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary Boston, MA
| | - Rebecca C. Stacy
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary Boston, MA
| | - Joseph F. Rizzo
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary Boston, MA
| | - Janey L. Wiggs
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary Boston, MA
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Majander A, João C, Rider AT, Henning GB, Votruba M, Moore AT, Yu-Wai-Man P, Stockman A. The Pattern of Retinal Ganglion Cell Loss in OPA1-Related Autosomal Dominant Optic Atrophy Inferred From Temporal, Spatial, and Chromatic Sensitivity Losses. Invest Ophthalmol Vis Sci 2017; 58:502-516. [PMID: 28125838 PMCID: PMC5283089 DOI: 10.1167/iovs.16-20309] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Progressive retinal ganglion cell (RGC) loss is the pathological hallmark of autosomal dominant optic atrophy (DOA) caused by pathogenic OPA1 mutations. The aim of this study was to conduct an in-depth psychophysical study of the visual losses in DOA and to infer any selective vulnerability of visual pathways subserved by different RGC subtypes. Methods We recruited 25 patients carrying pathogenic OPA1 mutations and age-matched healthy individuals. Spatial contrast sensitivity functions (SCSFs) and chromatic contrast sensitivity were quantified, the latter using the Cambridge Colour Test. In 11 patients, long (L) and short (S) wavelength-sensitive cone temporal acuities were measured as a function of target illuminance, and L-cone temporal contrast sensitivity (TCSF) as a function of temporal frequency. Results Spatial contrast sensitivity functions were abnormal, with the loss of sensitivity increasing with spatial frequency. Further, the highest L-cone temporal acuity fell on average by 10 Hz and the TCSFs by 0.66 log10 unit. Chromatic thresholds along the protan, deutan, and tritan axes were 8, 9, and 14 times higher than normal, respectively, with losses increasing with age and S-cone temporal acuity showing the most significant age-related decline. Conclusions Losses of midget parvocellular, parasol magnocellular, and bistratified koniocellular RGCs could account for the losses of high spatial frequency sensitivity and protan and deutan sensitivities, high temporal frequency sensitivity, and S-cone temporal and tritan sensitivities, respectively. The S-cone-related losses showed a significant deterioration with increasing patient age and could therefore prove useful biomarkers of disease progression in DOA.
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Affiliation(s)
- Anna Majander
- University College London, Institute of Ophthalmology, London, United Kingdom 2Moorfields Eye Hospital, London, United Kingdom 3Department of Ophthalmology, University of Helsinki, and Helsinki University Hospital, Helsinki, Finland
| | - Catarina João
- University College London, Institute of Ophthalmology, London, United Kingdom
| | - Andrew T Rider
- University College London, Institute of Ophthalmology, London, United Kingdom
| | - G Bruce Henning
- University College London, Institute of Ophthalmology, London, United Kingdom
| | - Marcela Votruba
- School of Optometry and Vision Sciences, Cardiff University Cardiff, and Cardiff Eye Unit, University Hospital Wales, Cardiff, United Kingdom
| | - Anthony T Moore
- University College London, Institute of Ophthalmology, London, United Kingdom 2Moorfields Eye Hospital, London, United Kingdom 5Ophthalmology Department, University of California-San Francisco School of Medicine, San Francisco, California, United States
| | - Patrick Yu-Wai-Man
- University College London, Institute of Ophthalmology, London, United Kingdom 2Moorfields Eye Hospital, London, United Kingdom 6Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University and Newcastle Eye Centre, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom
| | - Andrew Stockman
- University College London, Institute of Ophthalmology, London, United Kingdom
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Majander A, Bowman R, Poulton J, Antcliff RJ, Reddy MA, Michaelides M, Webster AR, Chinnery PF, Votruba M, Moore AT, Yu-Wai-Man P. Childhood-onset Leber hereditary optic neuropathy. Br J Ophthalmol 2017; 101:1505-1509. [PMID: 28314831 DOI: 10.1136/bjophthalmol-2016-310072] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 02/20/2017] [Accepted: 02/23/2017] [Indexed: 01/11/2023]
Abstract
BACKGROUND The onset of Leber hereditary optic neuropathy (LHON) is relatively rare in childhood. This study describes the clinical and molecular genetic features observed in this specific LHON subgroup. METHODS Our retrospective study consisted of a UK paediatric LHON cohort of 27 patients and 69 additional cases identified from a systematic review of the literature. Patients were included if visual loss occurred at the age of 12 years or younger with a confirmed pathogenic mitochondrial DNA mutation: m.3460G>A, m.11778G>A or m.14484T>C. RESULTS In the UK paediatric LHON cohort, three patterns of visual loss and progression were observed: (1) classical acute (17/27, 63%); (2) slowly progressive (4/27, 15%); and (3) insidious or subclinical (6/27, 22%). Diagnostic delays of 3-15 years occurred in children with an insidious mode of onset. Spontaneous visual recovery was more common in patients carrying the m.3460G>A and m.14484T>C mutations compared with the m.11778G>A mutation. Based a meta-analysis of 67 patients with available visual acuity data, 26 (39%) patients achieved a final best-corrected visual acuity (BCVA) ≥0.5 Snellen decimal in at least one eye, whereas 13 (19%) patients had a final BCVA <0.05 in their better seeing eye. CONCLUSIONS Although childhood-onset LHON carries a relatively better visual prognosis, approximately 1 in 5 patients will remain within the visual acuity criteria for legal blindness in the UK. The clinical presentation can be insidious and LHON should be considered in the differential diagnosis when faced with a child with unexplained subnormal vision and optic disc pallor.
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Affiliation(s)
- Anna Majander
- UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital, London, UK.,Department of Ophthalmology, Helsinki University Hospital, and University of Helsinki, Helsinki, Finland
| | | | - Joanna Poulton
- Nuffield Department of Obstetrics & Gynaecology, University of Oxford, Oxford, UK
| | | | | | - Michel Michaelides
- UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital, London, UK
| | - Andrew R Webster
- UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital, London, UK
| | - Patrick F Chinnery
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK.,Medical Research Council Mitochondrial Biology Unit, Cambridge, UK.,Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Marcela Votruba
- School of Optometry and Vision Sciences, Cardiff University and Cardiff Eye Unit, University Hospital Wales, Cardiff, UK
| | - Anthony T Moore
- UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital, London, UK.,Ophthalmology Department, UCSF School of Medicine, San Francisco, California, USA
| | - Patrick Yu-Wai-Man
- UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital, London, UK.,Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK.,Newcastle Eye Centre, Royal Victoria Infirmary, Newcastle upon Tyne, UK
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Case 9. Neuroophthalmology 2017. [DOI: 10.1007/978-1-4471-2410-8_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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A neurodegenerative perspective on mitochondrial optic neuropathies. Acta Neuropathol 2016; 132:789-806. [PMID: 27696015 PMCID: PMC5106504 DOI: 10.1007/s00401-016-1625-2] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Revised: 09/24/2016] [Accepted: 09/25/2016] [Indexed: 12/15/2022]
Abstract
Mitochondrial optic neuropathies constitute an important cause of chronic visual morbidity and registrable blindness in both the paediatric and adult population. It is a genetically heterogeneous group of disorders caused by both mitochondrial DNA (mtDNA) mutations and a growing list of nuclear genetic defects that invariably affect a critical component of the mitochondrial machinery. The two classical paradigms are Leber hereditary optic neuropathy (LHON), which is a primary mtDNA disorder, and autosomal dominant optic atrophy (DOA) secondary to pathogenic mutations within the nuclear gene OPA1 that encodes for a mitochondrial inner membrane protein. The defining neuropathological feature is the preferential loss of retinal ganglion cells (RGCs) within the inner retina but, rather strikingly, the smaller calibre RGCs that constitute the papillomacular bundle are particularly vulnerable, whereas melanopsin-containing RGCs are relatively spared. Although the majority of patients with LHON and DOA will present with isolated optic nerve involvement, some individuals will also develop additional neurological complications pointing towards a greater vulnerability of the central nervous system (CNS) in susceptible mutation carriers. These so-called “plus” phenotypes are mechanistically important as they put the loss of RGCs within the broader perspective of neuronal loss and mitochondrial dysfunction, highlighting common pathways that could be modulated to halt progressive neurodegeneration in other related CNS disorders. The management of patients with mitochondrial optic neuropathies still remains largely supportive, but the development of effective disease-modifying treatments is now within tantalising reach helped by major advances in drug discovery and delivery, and targeted genetic manipulation.
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Lopez Sanchez M, Crowston J, Mackey D, Trounce I. Emerging Mitochondrial Therapeutic Targets in Optic Neuropathies. Pharmacol Ther 2016; 165:132-52. [DOI: 10.1016/j.pharmthera.2016.06.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Indexed: 12/14/2022]
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Yu-Wai-Man P. Genetic manipulation for inherited neurodegenerative diseases: myth or reality? Br J Ophthalmol 2016; 100:1322-31. [PMID: 27002113 PMCID: PMC5050284 DOI: 10.1136/bjophthalmol-2015-308329] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 02/28/2016] [Indexed: 12/22/2022]
Abstract
Rare genetic diseases affect about 7% of the general population and over 7000 distinct clinical syndromes have been described with the majority being due to single gene defects. This review will provide a critical overview of genetic strategies that are being pioneered to halt or reverse disease progression in inherited neurodegenerative diseases. This field of research covers a vast area and only the most promising treatment paradigms will be discussed with a particular focus on inherited eye diseases, which have paved the way for innovative gene therapy paradigms, and mitochondrial diseases, which are currently generating a lot of debate centred on the bioethics of germline manipulation.
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Affiliation(s)
- Patrick Yu-Wai-Man
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK Newcastle Eye Centre, Royal Victoria Infirmary, Newcastle upon Tyne, UK NIHR Biomedical Research Centre at Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, UK
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Chen J, Riazifar H, Guan MX, Huang T. Modeling autosomal dominant optic atrophy using induced pluripotent stem cells and identifying potential therapeutic targets. Stem Cell Res Ther 2016; 7:2. [PMID: 26738566 PMCID: PMC4704249 DOI: 10.1186/s13287-015-0264-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 11/29/2015] [Accepted: 12/14/2015] [Indexed: 12/21/2022] Open
Abstract
Background Many retinal degenerative diseases are caused by the loss of retinal ganglion cells (RGCs). Autosomal dominant optic atrophy is the most common hereditary optic atrophy disease and is characterized by central vision loss and degeneration of RGCs. Currently, there is no effective treatment for this group of diseases. However, stem cell therapy holds great potential for replacing lost RGCs of patients. Compared with embryonic stem cells, induced pluripotent stem cells (iPSCs) can be derived from adult somatic cells, and they are associated with fewer ethical concerns and are less prone to immune rejection. In addition, patient-derived iPSCs may provide us with a cellular model for studying the pathogenesis and potential therapeutic agents for optic atrophy. Methods In this study, iPSCs were obtained from patients carrying an OPA1 mutation (OPA1+/−-iPSC) that were diagnosed with optic atrophy. These iPSCs were differentiated into putative RGCs, which were subsequently characterized by using RGC-specific expression markers BRN3a and ISLET-1. Results Mutant OPA1+/−-iPSCs exhibited significantly more apoptosis and were unable to efficiently differentiate into RGCs. However, with the addition of neural induction medium, Noggin, or estrogen, OPA1+/−-iPSC differentiation into RGCs was promoted. Conclusions Our results suggest that apoptosis mediated by OPA1 mutations plays an important role in the pathogenesis of optic atrophy, and both noggin and β-estrogen may represent potential therapeutic agents for OPA1-related optic atrophy. Electronic supplementary material The online version of this article (doi:10.1186/s13287-015-0264-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jing Chen
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA.
| | - Hamidreza Riazifar
- Department of Pediatrics, Division of Human Genetics, University of California, Irvine, CA, 92697, USA.
| | - Min-Xin Guan
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA.
| | - Taosheng Huang
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA.
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Rönnbäck C, Nissen C, Almind GJ, Grønskov K, Milea D, Larsen M. Genotype-phenotype heterogeneity of ganglion cell and inner plexiform layer deficit in autosomal-dominant optic atrophy. Acta Ophthalmol 2015; 93:762-6. [PMID: 26385429 DOI: 10.1111/aos.12835] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 07/22/2015] [Indexed: 12/01/2022]
Abstract
PURPOSE To describe the thickness of the combined ganglion cell and inner plexiform layers (GC-IPL) and the peripapillary retinal nerve fibre layer (RNFL) in patients with OPA1 c.983A>G or c.2708_2711delTTAG autosomal-dominant optic atrophy (ADOA). METHODS The study included 20 individuals with c.983A>G and nine individuals with c.2708_2711delTTAG. Data for comparison were drawn from 49, previously published, individuals with OPA1 c.2826_2836delinsGGATGCTCCA and 51 individuals with no OPA1 mutation. Subjects underwent refraction, best-corrected visual acuity assessment, axial length measurement and high-definition optical coherence tomography. RESULTS There was overlap in GC-IPL thickness in subjects younger than 20-30 years between the two new groups of ADOA patients and controls. Numerical decreases in GC-IPL thickness with age did not reach statistical significance in individuals with c.983A>G (p = 0.18) or in healthy controls (p = 0.22), but it did in individuals with c.2708_2711delTTAG (p = 0.02). Visual acuity decreased with decreasing GC-IPL thickness (p = 0.0006 in c.983A>G and p = 0.0084 in c.2708_2711delTTAG). Unlike c.2826_2836delinsGGATGCTCCA, individuals with c.983A>G or c.2708_2711delTTAG did not show a pattern of maximum GC-IPL deficit inferonasal of the fovea. CONCLUSION Genotype-phenotype heterogeneity in OPA1 ADOA is evident when inner retinal atrophy is examined as a function of age. Thus, a pronounced decline with age in GC-IPL thickness is observed in c.2708_2711delTTAG ADOA, an intermediate decline with age is observed in c.983A>G ADOA, whereas little or no change with age is observed in c.2826_2836delinsGGATGCTCCA ADOA. This genotype-phenotype heterogeneity may explain why some patients have progressive visual loss while others have a relatively stable prognosis.
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Affiliation(s)
- Cecilia Rönnbäck
- Department of Ophthalmology; Glostrup Hospital; Glostrup Denmark
- Faculty of Health Sciences; University of Copenhagen; Copenhagen Denmark
| | - Claus Nissen
- Department of Ophthalmology; Glostrup Hospital; Glostrup Denmark
- Faculty of Health Sciences; University of Copenhagen; Copenhagen Denmark
| | - Gitte J. Almind
- Faculty of Health Sciences; University of Copenhagen; Copenhagen Denmark
- Kennedy Center; Clinical Genetic Clinic; Copenhagen Denmark
| | - Karen Grønskov
- Faculty of Health Sciences; University of Copenhagen; Copenhagen Denmark
- Kennedy Center; Clinical Genetic Clinic; Copenhagen Denmark
| | - Dan Milea
- Department of Ophthalmology; Glostrup Hospital; Glostrup Denmark
- Singapore Eye Research Institute; Singapore National Eye Centre and Duke-NUS; Singapore Singapore
| | - Michael Larsen
- Department of Ophthalmology; Glostrup Hospital; Glostrup Denmark
- Faculty of Health Sciences; University of Copenhagen; Copenhagen Denmark
- Kennedy Center; National Eye Clinic; Copenhagen Denmark
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Park SW, Hwang JM. Optical coherence tomography shows early loss of the inferior temporal quadrant retinal nerve fiber layer in autosomal dominant optic atrophy. Graefes Arch Clin Exp Ophthalmol 2014; 253:135-41. [DOI: 10.1007/s00417-014-2852-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 10/27/2014] [Accepted: 10/30/2014] [Indexed: 11/25/2022] Open
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Rönnbäck C, Grønskov K, Larsen M. Retinal vessel diameters decrease with macular ganglion cell layer thickness in autosomal dominant optic atrophy and in healthy subjects. Acta Ophthalmol 2014; 92:670-4. [PMID: 24612963 DOI: 10.1111/aos.12378] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 01/29/2014] [Indexed: 11/27/2022]
Abstract
PURPOSE To investigate retinal trunk vessel diameters in subjects with autosomal dominant optic atrophy (ADOA) and mutation-free healthy relatives. METHODS This cross-sectional study included 52 ADOA patients with the optic atrophy 1 (OPA1) exon 28 (c.2826_2836delinsGGATGCTCCA) mutation (age 8.6-83.5 years) (best-corrected visual acuity (BCVA) 8-94 Early Treatment Diabetic Retinopathy Study (ETDRS) letters) and 55 mutation-free first-degree healthy relatives (age 8.9-68.7 years, BCVA 80-99). Analysis of fundus photographs provided integrated magnification-corrected measures of retinal vessel diameters (central retinal artery equivalent, CRAE, and central retinal vein equivalent, CRVE). Statistical analysis was corrected for age, gender, spherical equivalent refraction, axial length and mean arterial blood pressure (MABP) in a mixed model analysis. RESULTS Retinal arteries and veins were thinner in ADOA than in healthy controls (CRAE (mean ± 2 standard deviations (SD)) 153.9 ± 41.0 μm and CRVE 236.1 ± 42.0 μm in ADOA, CRAE 172.5 ± 25.0 μm (p = 0.0004) and CRVE 254.2 ± 37.6 μm (p = 0.0019) in healthy controls). MABP was comparable in the two groups (p = 0.18), and in both groups, CRAE decreased with increasing MABP (p = 0.01 and p < 0.0001, respectively). In ADOA, CRAE and CRVE decreased with age (p = 0.011 and p = 0.020, respectively) and CRAE decreased with decreasing BCVA (p = 0.011). In patients with ADOA and in healthy controls, CRAE decreased with decreasing average macular ganglion cell-inner plexiform layer (GC-IPL) thickness (p = 0.0017 and p = 0.0057, respectively). CONCLUSION Narrow retinal arteries and veins were associated not only with the severity of ADOA but with ganglion cell volume in patients with ADOA and in healthy subjects. This suggests that narrow vessels are a consequence rather than the cause of inner retinal hypoplasia or atrophy, although longitudinal studies are needed to confirm this hypothesis.
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Affiliation(s)
- Cecilia Rönnbäck
- Department of Ophthalmology; Glostrup Hospital; Glostrup Denmark
- Faculty of Health Sciences; University of Copenhagen; Copenhagen Denmark
| | - Karen Grønskov
- Faculty of Health Sciences; University of Copenhagen; Copenhagen Denmark
- Applied Human Molecular Genetics; Kennedy Center; Rigshospitalet; Copenhagen Denmark
| | - Michael Larsen
- Department of Ophthalmology; Glostrup Hospital; Glostrup Denmark
- Faculty of Health Sciences; University of Copenhagen; Copenhagen Denmark
- National Eye Clinic; Kennedy Center; Rigshospitalet; Copenhagen Denmark
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Rebolleda G, Diez-Alvarez L, Casado A, Sánchez-Sánchez C, de Dompablo E, González-López JJ, Muñoz-Negrete FJ. OCT: New perspectives in neuro-ophthalmology. Saudi J Ophthalmol 2014; 29:9-25. [PMID: 25859135 DOI: 10.1016/j.sjopt.2014.09.016] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 09/09/2014] [Indexed: 01/03/2023] Open
Abstract
Optical coherence tomography (OCT) has become essential to evaluate axonal/neuronal integrity, to assess disease progression in the afferent visual pathway and to predict visual recovery after surgery in compressive optic neuropathies. Besides that OCT testing is considered a powerful biomarker of neurodegeneration and a promising outcome measure for neuroprotective trials in multiple sclerosis (MS). Currently, spectral-domain OCT (SD-OCT) technology allows quantification of retinal individual layers. The Ganglion Cell layer (GCL) investigation has become one of the most useful tools from a neuro-ophthalmic perspective. It has a high correlation with perimetry, is predictive of future progression and is a highly sensitive, specific of several neuro-ophthalmic pathologies. Moreover the superior correlation with clinical measures compared to peripapillary retinal nerve fiber layer (pRNFL) suggests that GCL analysis might be a better approach to examine MS neurodegeneration. In disorders with optic disk edema, such as ischemic optic neuropathy, papillitis and papilledema, reduction in RNFL thickness caused by axonal atrophy is difficult to distinguish from a swelling resolution. In this setting, and in buried optic nerve head drusen (ONHD), GCL analysis may provide more accurate information than RNFL analysis and it might be an early structural indicator of irreversible neuronal loss. Enhanced depth imaging OCT (EDI-OCT) provides in vivo detail of ONHD, allowing to evaluate and quantify the drusen dimensions. OCT is improving our knowledge in hereditary optic neuropathies. Furthermore, there is growing evidence about the role of OCT as an adjunctive biomarker of disorders such as Alzheimer and Parkinson's disease.
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Affiliation(s)
- Gema Rebolleda
- Hospital Universitario Ramón y Cajal. IRYCIS, Ophthalmology Service, University of Alcala, Madrid, Spain
| | - Laura Diez-Alvarez
- Hospital Universitario Ramón y Cajal. IRYCIS, Ophthalmology Service, University of Alcala, Madrid, Spain
| | - Alfonso Casado
- Hospital Universitario Ramón y Cajal. IRYCIS, Ophthalmology Service, University of Alcala, Madrid, Spain
| | - Carmen Sánchez-Sánchez
- Hospital Universitario Ramón y Cajal. IRYCIS, Ophthalmology Service, University of Alcala, Madrid, Spain
| | - Elisabet de Dompablo
- Hospital Universitario Ramón y Cajal. IRYCIS, Ophthalmology Service, University of Alcala, Madrid, Spain
| | - Julio J González-López
- Hospital Universitario Ramón y Cajal. IRYCIS, Ophthalmology Service, University of Alcala, Madrid, Spain
| | - Francisco J Muñoz-Negrete
- Hospital Universitario Ramón y Cajal. IRYCIS, Ophthalmology Service, University of Alcala, Madrid, Spain
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Barboni P, Savini G, Cascavilla ML, Caporali L, Milesi J, Borrelli E, La Morgia C, Valentino ML, Triolo G, Lembo A, Carta A, De Negri A, Sadun F, Rizzo G, Parisi V, Pierro L, Bianchi Marzoli S, Zeviani M, Sadun AA, Bandello F, Carelli V. Early macular retinal ganglion cell loss in dominant optic atrophy: genotype-phenotype correlation. Am J Ophthalmol 2014; 158:628-36.e3. [PMID: 24907432 DOI: 10.1016/j.ajo.2014.05.034] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 05/25/2014] [Accepted: 05/27/2014] [Indexed: 12/26/2022]
Abstract
PURPOSE To assess the peripapillary retinal nerve fiber and macular retinal ganglion cell (RGC) loss in patients with dominant optic atrophy (DOA) stratified by OPA1 mutation type. DESIGN Cross-sectional study. METHODS We studied 39 patients from 28 pedigrees with DOA harboring heterozygous mutations in the OPA1 gene along with 45 age-matched healthy subjects. The retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GC-IPL) of patients with DOA were evaluated by optical coherence tomography (OCT) and compared to those of controls. Patients' eyes were divided into 4 groups based on increasing severity of visual loss (DOA1 to DOA4) and were stratified by OPA1 mutation type. RESULTS The average thicknesses of the RNFL and GC-IPL were smaller in patients with DOA than in healthy controls (P < 0.0001). RNFL analysis showed a significant reduction of the average, superior and inferior quadrants thicknesses in the DOA4 group compared to the DOA1 group (P = 0.001, P = 0.002 and P = 0.001, respectively). GC-IPL analysis showed a significant thinning in the superotemporal and superior sectors in the patients with DOA2 compared to those with DOA1 (P = 0.046 and P = 0.04, respectively). Stratifying by mutation type, average, superior and nasal RNFL thinning was significantly more severe in missense mutations and had a presumed dominant-negative effect compared to mutations causing haploinsufficiency. CONCLUSIONS The present study demonstrates that in DOA, loss of macular RGCs is the earliest pathologic event, better reflected by GC-IPL measurements, whereas RNFL thickness is a measure of spared axons in late stages of the disease. Thus, mild cases (DOA2) show significant macular RGC loss as opposed to substantial maintenance of RNFL thickness, which is significantly decreased only in severe cases (DOA4). A clear genotype/phenotype correlation emerged, stratifying OCT measures by OPA1 mutation type, missense mutations being the most severe.
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Affiliation(s)
- Piero Barboni
- Scientific Institute San Raffaele, Milan, Italy; Studio Oculistico d'Azeglio, Bologna, Italy.
| | | | | | - Leonardo Caporali
- Istituto di Ricerca e Cura a Carattere Scientifico (IRCCS), Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
| | | | | | - Chiara La Morgia
- Istituto di Ricerca e Cura a Carattere Scientifico (IRCCS), Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy; Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Maria Lucia Valentino
- Istituto di Ricerca e Cura a Carattere Scientifico (IRCCS), Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy; Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | | | - Andrea Lembo
- San Giuseppe Hospital, University Eye Clinic, Milan, Italy
| | - Arturo Carta
- Department of Ophthalmology, University of Parma, Italy
| | | | | | - Giovanni Rizzo
- Istituto di Ricerca e Cura a Carattere Scientifico (IRCCS), Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy; Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | | | | | - Stefania Bianchi Marzoli
- Neuro-ophthalmology Unit Department of Ophthalmology, Istituto di Ricerca e Cura a Carattere Scientifico (IRCCS) Istituto Auxologico Italiano, Milano, Italy
| | - Massimo Zeviani
- Unit of Molecular Neurogenetics, Foundation C. Besta Neurological Institute, Istituto di Ricerca e Cura a Carattere Scientifico (IRCCS), Milan, Italy; Medical Research Council Mitochondrial Biology Unit, Cambridge, UK
| | - Alfredo A Sadun
- Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | | | - Valerio Carelli
- Istituto di Ricerca e Cura a Carattere Scientifico (IRCCS), Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy; Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
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Yu-Wai-Man P, Votruba M, Moore AT, Chinnery PF. Treatment strategies for inherited optic neuropathies: past, present and future. Eye (Lond) 2014; 28:521-37. [PMID: 24603424 PMCID: PMC4017118 DOI: 10.1038/eye.2014.37] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Accepted: 01/22/2014] [Indexed: 12/16/2022] Open
Abstract
Bilateral visual loss secondary to inherited optic neuropathies is an important cause of registrable blindness among children and young adults. The two prototypal disorders seen in clinical practice are Leber hereditary optic neuropathy (LHON) and autosomal dominant optic atrophy (DOA). About 90% of LHON cases are due to one of three mitochondrial DNA (mtDNA) point mutations: m.3460G>A, m.11778G>A, and m.14484T>C, which affect critical complex I subunits of the mitochondrial respiratory chain. The majority of patients with DOA harbour pathogenic mutations within OPA1, a nuclear gene that codes for a multifunctional inner mitochondrial membrane protein. Despite their contrasting genetic basis, LHON and DOA share overlapping pathological and clinical features that serve to highlight the striking tissue-specific vulnerability of the retinal ganglion cell (RGC) layer to disturbed mitochondrial function. In addition to severe visual loss secondary to progressive optic nerve degeneration, a subgroup of patients will also develop a more aggressive syndromic phenotype marked by significant neurological deficits. The management of LHON and DOA remains largely supportive, but major advances in our understanding of the mechanisms underpinning RGC loss in these two disorders are paving the way for novel forms of treatment aimed at halting or reversing visual deterioration at different stages of the disease process. In addition to neuroprotective strategies for rescuing RGCs from irreversible cell death, innovative in vitro fertilisation techniques are providing the tantalising prospect of preventing the germline transmission of pathogenic mtDNA mutations, eradicating in so doing the risk of disease in future generations.
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Affiliation(s)
- P Yu-Wai-Man
- 1] Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK [2] Departments of Neurology and Ophthalmology, Royal Victoria Infirmary, Newcastle upon Tyne, UK [3] Moorfields Eye Hospital, London, UK [4] NIHR Biomedical Research Centre, UCL Institute of Ophthalmology, University College London, London, UK
| | - M Votruba
- 1] School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK [2] Cardiff Eye Unit, University Hospital of Wales, Cardiff, UK
| | - A T Moore
- 1] Moorfields Eye Hospital, London, UK [2] NIHR Biomedical Research Centre, UCL Institute of Ophthalmology, University College London, London, UK
| | - P F Chinnery
- 1] Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK [2] Departments of Neurology and Ophthalmology, Royal Victoria Infirmary, Newcastle upon Tyne, UK
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Selective retinal ganglion cell loss in familial dysautonomia. J Neurol 2014; 261:702-9. [PMID: 24487827 DOI: 10.1007/s00415-014-7258-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 01/15/2014] [Accepted: 01/17/2014] [Indexed: 10/25/2022]
Abstract
To define the retinal phenotype of subjects with familial dysautonomia (FD). A cross-sectional study was carried out in 90 subjects divided in three groups of 30 each (FD subjects, asymptomatic carriers and controls). The study was developed at the Dysautonomia Center, New York University Medical Center. All subjects underwent spectral domain optical coherence tomography (OCT) and full neuro-ophthalmic examinations. In a subset of affected subjects, visual evoked potentials and microperimetry were also obtained. We compared the retinal nerve fiber layer (RNFL) thickness from OCT between the three groups. OCT showed loss of the RNFL in all FD subjects predominantly in the maculopapillary region (63 % temporally, p < 0.0001; and 21 % nasally, p < 0.005). RNFL loss was greatest in older FD subjects and was associated with decreased visual acuity and color vision, central visual field defects, temporal optic nerve pallor, and delayed visual evoked potentials. Asymptomatic carriers of the FD gene mutation all had thinner RNFL (12 % globally, p < 0.005). OCT and clinical neuro-ophthalmological findings suggest that maculopapillary ganglion cells are primarily affected in FD subjects, leading to a specific optic nerve damage that closely resembles mitochondrial optic neuropathies. This raises the possibility that reduced IKAP levels may affect mitochondrial proteins and their function in the nervous system, particularly in the retina.
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Marella M, Patki G, Matsuno-Yagi A, Yagi T. Complex I inhibition in the visual pathway induces disorganization of the node of Ranvier. Neurobiol Dis 2013; 58:281-8. [PMID: 23816754 PMCID: PMC3767286 DOI: 10.1016/j.nbd.2013.06.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 06/10/2013] [Accepted: 06/15/2013] [Indexed: 01/02/2023] Open
Abstract
Mitochondrial defects can have significant consequences on many aspects of neuronal physiology. In particular, deficiencies in the first enzyme complex of the mitochondrial respiratory chain (complex I) are considered to be involved in a number of human neurodegenerative diseases. The current work highlights a tight correlation between the inhibition of complex I and the state of axonal myelination of the optic nerve. Exposing the visual pathway of rats to rotenone, a complex I inhibitor, resulted in disorganization of the node of Ranvier. The structure and function of the node depend on specific cell adhesion molecules, among others, CASPR (contactin associated protein) and contactin. CASPR and contactin are both on the axonal surfaces and need to be associated to be able to anchor their myelin counterpart. Here we show that inhibition of mitochondrial complex I by rotenone in rats induces reactive oxygen species, disrupts the interaction of CASPR and contactin couple, and thus damages the organization and function of the node of Ranvier. Demyelination of the optic nerve occurs as a consequence which is accompanied by a loss of vision. The physiological impairment could be reversed by introducing an alternative NADH dehydrogenase to the mitochondria of the visual system. The restoration of the nodal structure was specifically correlated with visual recovery in the treated animal.
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Affiliation(s)
- Mathieu Marella
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
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Lathrop KL, Steketee MB. Mitochondrial Dynamics in Retinal Ganglion Cell Axon Regeneration and Growth Cone Guidance. JOURNAL OF OCULAR BIOLOGY 2013; 1:9. [PMID: 24616897 PMCID: PMC3946936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Failed axon regeneration and retinal ganglion cell (RGC) death after trauma or disease, including glaucomatous and mitochondrial optic neuropathies, are increasingly linked to mitochondrial dysfunction. Mitochondria are highly dynamic organelles whose size, organization, and function are regulated by a balance between mitochondrial fission and fusion. Mitochondria are ubiquitous in axonal growth cones both in vitro and in vivo and during development and regeneration. However, the roles that mitochondrial fission and fusion dynamics play in the growth cone during axon regeneration are largely unstudied. Here we discuss recent data suggesting mitochondria in the distal axon and growth cone play a central role in axon growth by integrating intrinsic axon growth states with signaling from extrinsic cues. Mitochondrial fission and fusion are intrinsically regulated in the distal axon in the growth cones of acutely purified embryonic and postnatal RGCs with differing intrinsic axon growth potentials. These differences in fission and fusion correlate with differences in mitochondrial bioenergetics; embryonic RGCs with high intrinsic axon growth potential rely more on glycolysis whereas RGCs with low intrinsic axon growth potential rely more on oxidative phosphorylation. Mitochondrial fission and fusion are also differentially modulated by KLFs that either promote or suppress intrinsic axon growth, and altering the balance between mitochondrial fission and fusion can differentially regulate axon growth rate and growth cone guidance responses to both inhibitory and permissive guidance cues.
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Affiliation(s)
- Kira L. Lathrop
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA
- Swanson School of Engineering, Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Michael B. Steketee
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
- Louis J. Fox Center for Vision Restoration, University of Pittsburgh, Pittsburgh, PA, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
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SDOCT thickness measurements of various retinal layers in patients with autosomal dominant optic atrophy due to OPA1 mutations. BIOMED RESEARCH INTERNATIONAL 2013; 2013:121398. [PMID: 24024178 PMCID: PMC3760180 DOI: 10.1155/2013/121398] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 07/16/2013] [Accepted: 07/19/2013] [Indexed: 12/27/2022]
Abstract
Purpose. To specify thickness values of various retinal layers on macular spectral domain Optical Coherence Tomography (SDOCT) scans in patients with autosomal dominant optic atrophy (ADOA) compared to healthy controls. Methods. SDOCT volume scans of 7 patients with ADOA (OPA-1 mutation) and 14 healthy controls were quantitatively analyzed using manual grading software. Mean thickness values for the ETDRS grid subfields 5–8 were calculated for the spaces neurosensory retina, retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), a combined space of inner plexiform layer/outer plexiform layer/inner nuclear layer (IPL+INL+OPL), and a combined space of outer nuclear layer/photoreceptor layers (ONL+PL). Results. ADOA patients showed statistically significant lower retinal thickness values than controls (P < 0.01). RNFL (P < 0.001) and GCL thicknesses (P < 0.001) were significantly lower in ADOA patients. There was no difference in IPL+INL+OPL and in ONL+PL thickness. Conclusion. Manual subanalysis of macular SDOCT volume scans allowed detailed subanalysis of various retinal layers. Not only RNFL but also GCL thicknesses are reduced in the macular area of ADOA patients whereas subjacent layers are not involved. Together with clinical findings, macular SDOCT helps to identify patients with suspicion for hereditary optic neuropathy before genetic analysis confirms the diagnosis.
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40
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Mitochondrial disorders: aetiologies, models systems, and candidate therapies. Trends Genet 2013; 29:488-97. [PMID: 23756086 DOI: 10.1016/j.tig.2013.05.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 05/01/2013] [Accepted: 05/03/2013] [Indexed: 01/14/2023]
Abstract
It has become evident that many human disorders are characterised by mitochondrial dysfunction either at a primary level, due to mutations in genes whose encoded products are involved in oxidative phosphorylation, or at a secondary level, due to the accumulation of mitochondrial DNA (mtDNA) mutations. This has prompted keen interest in the development of cell and animal models and in exploring innovative therapeutic strategies to modulate the mitochondrial deficiencies observed in these diseases. Key advances in these areas are outlined in this review, with a focus on Leber hereditary optic neuropathy (LHON). This exciting field is set to grow exponentially and yield many candidate therapies to treat this class of disease.
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Affiliation(s)
- Patrick Yu-Wai-Man
- 1 Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic
Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, UK
| | - Patrick F. Chinnery
- 1 Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic
Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, UK
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Klebe S, Depienne C, Gerber S, Challe G, Anheim M, Charles P, Fedirko E, Lejeune E, Cottineau J, Brusco A, Dollfus H, Chinnery PF, Mancini C, Ferrer X, Sole G, Destée A, Mayer JM, Fontaine B, de Seze J, Clanet M, Ollagnon E, Busson P, Cazeneuve C, Stevanin G, Kaplan J, Rozet JM, Brice A, Durr A. Spastic paraplegia gene 7 in patients with spasticity and/or optic neuropathy. ACTA ACUST UNITED AC 2013; 135:2980-93. [PMID: 23065789 DOI: 10.1093/brain/aws240] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Mutations in the spastic paraplegia 7 (SPG7) gene encoding paraplegin are responsible for autosomal recessive hereditary spasticity. We screened 135 unrelated index cases, selected in five different settings: SPG7-positive patients detected during SPG31 analysis using SPG31/SPG7 multiplex ligation-dependent probe amplification (n = 7); previously reported ambiguous SPG7 cases (n = 5); patients carefully selected on the basis of their phenotype (spasticity of the lower limbs with cerebellar signs and/or cerebellar atrophy on magnetic resonance imaging/computer tomography scan and/or optic neuropathy and without other signs) (n = 24); patients with hereditary spastic paraparesis referred consecutively from attending neurologists and the national reference centre in a diagnostic setting (n = 98); and the index case of a four-generation family with autosomal dominant optic neuropathy but no spasticity linked to the SPG7 locus. We identified two SPG7 mutations in 23/134 spastic patients, 21% of the patients selected according to phenotype but only 8% of those referred directly. Our results confirm the pathogenicity of Ala510Val, which was the most frequent mutation in our series (65%) and segregated at the homozygous state with spastic paraparesis in a large family with autosomal recessive inheritance. All SPG7-positive patients tested had optic neuropathy or abnormalities revealed by optical coherence tomography, indicating that abnormalities in optical coherence tomography could be a clinical biomarker for SPG7 testing. In addition, the presence of late-onset very slowly progressive spastic gait (median age 39 years, range 18-52 years) associated with cerebellar ataxia (39%) or cerebellar atrophy (47%) constitute, with abnormal optical coherence tomography, key features pointing towards SPG7-testing. Interestingly, three relatives of patients with heterozygote SPG7 mutations had cerebellar signs and atrophy, or peripheral neuropathy, but no spasticity of the lower limbs, suggesting that SPG7 mutations at the heterozygous state might predispose to late-onset neurodegenerative disorders, mimicking autosomal dominant inheritance. Finally, a novel missense SPG7 mutation at the heterozygous state (Asp411Ala) was identified as the cause of autosomal dominant optic neuropathy in a large family, indicating that some SPG7 mutations can occasionally be dominantly inherited and be an uncommon cause of isolated optic neuropathy. Altogether, these results emphasize the clinical variability associated with SPG7 mutations, ranging from optic neuropathy to spastic paraplegia, and support the view that SPG7 screening should be carried out in both conditions.
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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]
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Steketee MB, Moysidis SN, Weinstein JE, Kreymerman A, Silva JP, Iqbal S, Goldberg JL. Mitochondrial dynamics regulate growth cone motility, guidance, and neurite growth rate in perinatal retinal ganglion cells in vitro. Invest Ophthalmol Vis Sci 2012; 53:7402-11. [PMID: 23049086 DOI: 10.1167/iovs.12-10298] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Retinal ganglion cell (RGC) death and failed axonal regeneration after trauma or disease, including glaucomatous and mitochondrial optic neuropathies, are linked increasingly to dysfunctional mitochondrial dynamics. However, how mitochondrial dynamics influence axon growth largely is unstudied. We examined intrinsic mitochondrial organization in embryonic and postnatal RGCs and the roles that mitochondrial dynamics have in regulating neurite growth and guidance. METHODS RGCs were isolated from embryonic day 20 (E20) or postnatal days 5 to 7 (P5-7) Sprague-Dawley rats by anti-Thy1 immunopanning. After JC-1 loading, mitochondria were analyzed in acutely purified RGCs by flow cytometry and in RGC neurites by fluorescence microscopy. Intrinsic axon growth was modulated by overexpressing Krüppel-like family (KLF) transcription factors, or mitochondrial dynamics were altered by inhibiting dynamin related protein-1 (DRP-1) pharmacologically or by overexpressing mitofusin-2 (Mfn-2). Mitochondrial organization, neurite growth, and growth cone motility and guidance were analyzed. RESULTS Mitochondrial dynamics and function are regulated developmentally in acutely purified RGCs and in nascent RGC neurites. Mitochondrial dynamics are modulated differentially by KLFs that promote or suppress growth. Acutely inhibiting mitochondrial fission reversibly suppressed axon growth and lamellar extension. Inhibiting DRP-1 or overexpressing Mfn-2 altered growth cone responses to chondroitin sulfate proteoglycan, netrin-1, and fibronectin. CONCLUSIONS These results support the hypothesis that mitochondria locally modulate signaling in the distal neurite and growth cone to affect the direction and the rate of neurite growth.
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Abstract
The hereditary optic neuropathies are inherited disorders in which optic nerve dysfunction is a prominent feature in the phenotypic expression of disease. Optic neuropathy may be primarily an isolated finding, such as in Leber hereditary optic neuropathy and dominant optic atrophy, or part of a multisystem disorder. The pathophysiological mechanisms underlying the hereditary optic neuropathies involve mitochondrial dysfunction owing to mutations in mitochondrial or nuclear DNA that encodes proteins essential to mitochondrial function. Effective treatments are limited, and current management includes therapies directed at enhancing mitochondrial function and preventing oxidative damage, as well as genetic counselling, and supportive and symptomatic measures. New therapies, including gene therapy, are emerging via animal models and human clinical trials. Leber hereditary optic neuropathy, in particular, provides a unique model for testing promising treatments owing to its characteristic sequential bilateral involvement and the accessibility of target tissue within the eye. Lessons learned from treatment of the hereditary optic neuropathies may have therapeutic implications for other disorders of presumed mitochondrial dysfunction. In this Review, the natural history of the common inherited optic neuropathies, the presumed pathogenesis of several of these disorders, and the literature to date regarding potential therapies are summarized.
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Affiliation(s)
- Nancy J Newman
- Neuro-ophthalmology Unit, Department of Ophthalmology, Neurology and Neurological Surgery, Emory University School of Medicine, 1365-B Clifton Road NE, Atlanta, GA 30322, USA
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Disorders of the optic nerve in mitochondrial cytopathies: new ideas on pathogenesis and therapeutic targets. Curr Neurol Neurosci Rep 2012; 12:308-17. [PMID: 22392506 PMCID: PMC3342502 DOI: 10.1007/s11910-012-0260-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Mitochondrial cytopathies are a heterogeneous group of human disorders triggered by disturbed mitochondrial function. This can be due to primary mitochondrial DNA mutations or nuclear defects affecting key components of the mitochondrial machinery. Optic neuropathy is a frequent disease manifestation and the degree of visual failure can be profound, with a severe impact on the patient’s quality of life. This review focuses on the major mitochondrial disorders exhibiting optic nerve involvement, either as the defining clinical feature or as an additional component of a more extensive phenotype. Over the past decade, significant progress has been achieved in our basic understanding of Leber hereditary optic neuropathy and autosomal-dominant optic atrophy—the two classical paradigms for these mitochondrial optic neuropathies. There are currently limited treatments for these blinding ocular disorders and, ultimately, the aim is to translate these major advances into tangible benefits for patients and their families.
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Reis A, Mateus C, Viegas T, Florijn R, Bergen A, Silva E, Castelo-Branco M. Physiological evidence for impairment in autosomal dominant optic atrophy at the pre-ganglion level. Graefes Arch Clin Exp Ophthalmol 2012; 251:221-34. [DOI: 10.1007/s00417-012-2112-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2012] [Revised: 06/08/2012] [Accepted: 07/02/2012] [Indexed: 11/28/2022] Open
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Lenaers G, Hamel C, Delettre C, Amati-Bonneau P, Procaccio V, Bonneau D, Reynier P, Milea D. Dominant optic atrophy. Orphanet J Rare Dis 2012; 7:46. [PMID: 22776096 PMCID: PMC3526509 DOI: 10.1186/1750-1172-7-46] [Citation(s) in RCA: 171] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Accepted: 03/15/2012] [Indexed: 11/18/2022] Open
Abstract
Definition of the disease Dominant Optic Atrophy (DOA) is a neuro-ophthalmic condition characterized by a bilateral degeneration of the optic nerves, causing insidious visual loss, typically starting during the first decade of life. The disease affects primary the retinal ganglion cells (RGC) and their axons forming the optic nerve, which transfer the visual information from the photoreceptors to the lateral geniculus in the brain. Epidemiology The prevalence of the disease varies from 1/10000 in Denmark due to a founder effect, to 1/30000 in the rest of the world. Clinical description DOA patients usually suffer of moderate visual loss, associated with central or paracentral visual field deficits and color vision defects. The severity of the disease is highly variable, the visual acuity ranging from normal to legal blindness. The ophthalmic examination discloses on fundoscopy isolated optic disc pallor or atrophy, related to the RGC death. About 20% of DOA patients harbour extraocular multi-systemic features, including neurosensory hearing loss, or less commonly chronic progressive external ophthalmoplegia, myopathy, peripheral neuropathy, multiple sclerosis-like illness, spastic paraplegia or cataracts. Aetiology Two genes (OPA1, OPA3) encoding inner mitochondrial membrane proteins and three loci (OPA4, OPA5, OPA8) are currently known for DOA. Additional loci and genes (OPA2, OPA6 and OPA7) are responsible for X-linked or recessive optic atrophy. All OPA genes yet identified encode mitochondrial proteins embedded in the inner membrane and ubiquitously expressed, as are the proteins mutated in the Leber Hereditary Optic Neuropathy. OPA1 mutations affect mitochondrial fusion, energy metabolism, control of apoptosis, calcium clearance and maintenance of mitochondrial genome integrity. OPA3 mutations only affect the energy metabolism and the control of apoptosis. Diagnosis Patients are usually diagnosed during their early childhood, because of bilateral, mild, otherwise unexplained visual loss related to optic discs pallor or atrophy, and typically occurring in the context of a family history of DOA. Optical Coherence Tomography further discloses non-specific thinning of retinal nerve fiber layer, but a normal morphology of the photoreceptors layers. Abnormal visual evoked potentials and pattern ERG may also reflect the dysfunction of the RGCs and their axons. Molecular diagnosis is provided by the identification of a mutation in the OPA1 gene (75% of DOA patients) or in the OPA3 gene (1% of patients). Prognosis Visual loss in DOA may progress during puberty until adulthood, with very slow subsequent chronic progression in most of the cases. On the opposite, in DOA patients with associated extra-ocular features, the visual loss may be more severe over time. Management To date, there is no preventative or curative treatment in DOA; severely visually impaired patients may benefit from low vision aids. Genetic counseling is commonly offered and patients are advised to avoid alcohol and tobacco consumption, as well as the use of medications that may interfere with mitochondrial metabolism. Gene and pharmacological therapies for DOA are currently under investigation.
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Affiliation(s)
- Guy Lenaers
- Institut des Neurosciences de Montpellier, U1051 de l'INSERM, Université de Montpellier I et II, BP 74103, F-34091 Montpellier cedex 05, France.
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Yu-Wai-Man P, Chinnery PF. Reply: Spastic paraplegia in ‘dominant optic atrophy plus’ phenotype due to OPA1 mutation. Brain 2011; 134:e196. [PMID: 26281626 PMCID: PMC3212709 DOI: 10.1093/brain/awr102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Patrick Yu-Wai-Man
- Mitochondrial Research Group, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, UK; Department of Ophthalmology, Royal Victoria Infirmary, Newcastle upon Tyne, NE1 4LP, UK
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Ganapathy PS, Perry RL, Tawfik A, Smith RM, Perry E, Roon P, Bozard BR, Ha Y, Smith SB. Homocysteine-mediated modulation of mitochondrial dynamics in retinal ganglion cells. Invest Ophthalmol Vis Sci 2011; 52:5551-8. [PMID: 21642619 DOI: 10.1167/iovs.11-7256] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
PURPOSE To evaluate the effect of excess homocysteine on the regulation of retinal ganglion cell mitochondrial dynamics. METHODS Mice deficient in cystathionine-β-synthase (cbs) were used as a model of hyperhomocysteinemia. Gene and protein expression analyses of Opa1 and Fis1 were performed on cbs⁺/⁻ neural retinas. Mitochondria within retinal ganglion cell axons underwent systematic ultrastructural analysis to measure area, length, width, and the distance between the mitochondria and the axon wall. Primary mouse ganglion cells were cultured, treated with homocysteine, and assessed for levels of Opa1 and Fis1 protein, the number of mitochondria per length of neurite, and levels of cleaved caspase-3. RESULTS Opa1 and Fis1 protein levels in cbs⁺/⁻ neural retinas were elevated to 191.00% ± 26.40% and 226.20% ± 4.57%, respectively, compared with wild-type. Mitochondria of cbs⁺/⁻ retinas were smaller in all parameters studied, including area (0.32 ± 0.01 μm² vs. 0.42 ± 0.02 μm²), compared with wild-type. Primary ganglion cells treated with homocysteine had elevations in Opa1 and Fis1 proteins, a significantly higher number of mitochondria per length of neurite (0.1781 ± 0.017 vs. 0.1156 ± 0.012), and significantly higher levels of cleaved caspase-3 compared with control. CONCLUSIONS This study provides the first evidence that homocysteine-induced ganglion cell loss involves the dysregulation of mitochondrial dynamics, both in vivo and in vitro. The present data suggest increased mitochondrial fission as a novel mechanism of homocysteine toxicity to neurons. Of particular relevance are glaucoma and Alzheimer's disease, neurodegenerative diseases that are associated with hyperhomocysteinemia and, more recently, have implicated increased mitochondrial fission in their pathogeneses.
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Affiliation(s)
- Preethi S Ganapathy
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta, Georgia, USA
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