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Hernansanz-Agustín P, Morales-Vidal C, Calvo E, Natale P, Martí-Mateos Y, Jaroszewicz SN, Cabrera-Alarcón JL, Acín-Pérez R, López-Montero I, Vázquez J, Enríquez JA. A transmitochondrial sodium gradient controls membrane potential in mammalian mitochondria. Cell 2024:S0092-8674(24)00974-7. [PMID: 39303716 DOI: 10.1016/j.cell.2024.08.045] [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: 01/22/2024] [Revised: 07/02/2024] [Accepted: 08/21/2024] [Indexed: 09/22/2024]
Abstract
Eukaryotic cell function and survival rely on the use of a mitochondrial H+ electrochemical gradient (Δp), which is composed of an inner mitochondrial membrane (IMM) potential (ΔΨmt) and a pH gradient (ΔpH). So far, ΔΨmt has been assumed to be composed exclusively of H+. Here, using a rainbow of mitochondrial and nuclear genetic models, we have discovered that a Na+ gradient equates with the H+ gradient and controls half of ΔΨmt in coupled-respiring mammalian mitochondria. This parallelism is controlled by the activity of the long-sought Na+-specific Na+/H+ exchanger (mNHE), which we have identified as the P-module of complex I (CI). Deregulation of this mNHE function, without affecting the canonical enzymatic activity or the assembly of CI, occurs in Leber's hereditary optic neuropathy (LHON), which has profound consequences in ΔΨmt and mitochondrial Ca2+ homeostasis and explains the previously unknown molecular pathogenesis of this neurodegenerative disease.
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Affiliation(s)
- Pablo Hernansanz-Agustín
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid 28029, Spain; Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable, Madrid, Spain.
| | - Carmen Morales-Vidal
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid 28029, Spain
| | - Enrique Calvo
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid 28029, Spain; Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBER-CV), Madrid, Spain
| | - Paolo Natale
- Departamento de Química-Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid (UCM), Madrid, Spain; Instituto de Investigación Biomédica Hospital Doce de Octubre (imas12), Madrid, Spain
| | - Yolanda Martí-Mateos
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid 28029, Spain
| | | | | | - Rebeca Acín-Pérez
- Department of Medicine, Endocrinology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Iván López-Montero
- Departamento de Química-Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid (UCM), Madrid, Spain; Instituto de Investigación Biomédica Hospital Doce de Octubre (imas12), Madrid, Spain; Instituto Pluridisciplinar-UCM, Madrid, Spain
| | - Jesús Vázquez
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid 28029, Spain; Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBER-CV), Madrid, Spain
| | - José Antonio Enríquez
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid 28029, Spain; Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable, Madrid, Spain.
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2
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Jin L, Gan D, He W, Wu N, Xiang S, Wei Y, Eriani G, Ji Y, Guan MX, Wang M. Mitochondrial tRNA Glu 14693A>G Mutation, an "Enhancer" to the Phenotypic Expression of Leber's Hereditary Optic Neuropathy. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2401856. [PMID: 39264244 DOI: 10.1002/advs.202401856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 08/12/2024] [Indexed: 09/13/2024]
Abstract
Leber's hereditary optic neuropathy (LHON), a maternally inherited ocular disease, is predominantly caused by mitochondrial DNA (mtDNA) mutations. Mitochondrial tRNA variants are hypothesized to amplify the pathogenic impact of three primary mutations. However, the exact mechanisms remained unclear. In the present study, the synergistic effect of the tRNAGlu 14693A>G and ND6 14484T>C mutations in three Chinese families affected by LHON is investigated. The m.14693A>G mutation nearly abolishes the pseudouridinylation at position 55 of tRNAGlu, leading to structural abnormalities, decreased stability, aberrant mitochondrial protein synthesis, and increased autophagy. In contrast, the ND6 14484T>C mutation predominantly impairs complex I function, resulting in heightened apoptosis and virtually no induction of mitochondrial autophagy compared to control cell lines. The presence of dual mutations in the same cell lines exhibited a coexistence of both upregulated cellular stress responses to mitochondrial damage, indicating a scenario of autophagy and mutation dysregulation within these dual-mutant cell lines. The data proposes a novel hypothesis that mitochondrial tRNA gene mutations generally lead to increased mitochondrial autophagy, while mutations in genes encoding mitochondrial proteins typically induce apoptosis, shedding light on the intricate interplay between different genetic factors in the manifestation of LHON.
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Affiliation(s)
- Lihao Jin
- Center for Genetic Medicine, the Fourth Affiliated Hospital of School of Medicine, and International School of Medicine, International institutes of Medicine, Zhejiang University, Yiwu, 322000, China
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine and National Clinical Research Center for Child Health, Hangzhou, 310058, China
- Institute of Genetics, Zhejiang University International School of Medicine, Hangzhou, 310058, China
| | - Dingyi Gan
- Center for Genetic Medicine, the Fourth Affiliated Hospital of School of Medicine, and International School of Medicine, International institutes of Medicine, Zhejiang University, Yiwu, 322000, China
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine and National Clinical Research Center for Child Health, Hangzhou, 310058, China
- Institute of Genetics, Zhejiang University International School of Medicine, Hangzhou, 310058, China
| | - Wentao He
- Center for Genetic Medicine, the Fourth Affiliated Hospital of School of Medicine, and International School of Medicine, International institutes of Medicine, Zhejiang University, Yiwu, 322000, China
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine and National Clinical Research Center for Child Health, Hangzhou, 310058, China
- Institute of Genetics, Zhejiang University International School of Medicine, Hangzhou, 310058, China
| | - Na Wu
- Center for Genetic Medicine, the Fourth Affiliated Hospital of School of Medicine, and International School of Medicine, International institutes of Medicine, Zhejiang University, Yiwu, 322000, China
- Institute of Genetics, Zhejiang University International School of Medicine, Hangzhou, 310058, China
| | - Shuchenlu Xiang
- Center for Genetic Medicine, the Fourth Affiliated Hospital of School of Medicine, and International School of Medicine, International institutes of Medicine, Zhejiang University, Yiwu, 322000, China
- Institute of Genetics, Zhejiang University International School of Medicine, Hangzhou, 310058, China
| | - Yinsheng Wei
- Center for Genetic Medicine, the Fourth Affiliated Hospital of School of Medicine, and International School of Medicine, International institutes of Medicine, Zhejiang University, Yiwu, 322000, China
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine and National Clinical Research Center for Child Health, Hangzhou, 310058, China
- Institute of Genetics, Zhejiang University International School of Medicine, Hangzhou, 310058, China
| | - Gilbert Eriani
- Architecture et Réactivité de l'ARN, UPR9002 Centre National de la Recherche Scientifique, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire, 2 allée Konrad Roentgen, Strasbourg, 67084, France
| | - Yanchun Ji
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine and National Clinical Research Center for Child Health, Hangzhou, 310058, China
- Institute of Genetics, Zhejiang University International School of Medicine, Hangzhou, 310058, China
| | - Min-Xin Guan
- Center for Genetic Medicine, the Fourth Affiliated Hospital of School of Medicine, and International School of Medicine, International institutes of Medicine, Zhejiang University, Yiwu, 322000, China
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine and National Clinical Research Center for Child Health, Hangzhou, 310058, China
- Institute of Genetics, Zhejiang University International School of Medicine, Hangzhou, 310058, China
| | - Meng Wang
- Center for Genetic Medicine, the Fourth Affiliated Hospital of School of Medicine, and International School of Medicine, International institutes of Medicine, Zhejiang University, Yiwu, 322000, China
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine and National Clinical Research Center for Child Health, Hangzhou, 310058, China
- Institute of Genetics, Zhejiang University International School of Medicine, Hangzhou, 310058, China
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3
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Peng SY, Chen CY, Chen H, Yang YP, Wang ML, Tsai FT, Chien CS, Weng PY, Tsai ET, Wang IC, Hsu CC, Lin TC, Hwang DK, Chen SJ, Chiou SH, Chiao CC, Chien Y. Inhibition of angiogenesis by the secretome from iPSC-derived retinal ganglion cells with Leber's hereditary optic neuropathy-like phenotypes. Biomed Pharmacother 2024; 178:117270. [PMID: 39126773 DOI: 10.1016/j.biopha.2024.117270] [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: 04/23/2024] [Revised: 08/01/2024] [Accepted: 08/05/2024] [Indexed: 08/12/2024] Open
Abstract
The blood supply in the retina ensures photoreceptor function and maintains regular vision. Leber's hereditary optic neuropathy (LHON), caused by the mitochondrial DNA mutations that deteriorate complex I activity, is characterized by progressive vision loss. Although some reports indicated retinal vasculature abnormalities as one of the comorbidities in LHON, the paracrine influence of LHON-affected retinal ganglion cells (RGCs) on vascular endothelial cell physiology remains unclear. To address this, we established an in vitro model of mitochondrial complex I deficiency using induced pluripotent stem cell-derived RGCs (iPSC-RGCs) treated with a mitochondrial complex I inhibitor rotenone (Rot) to recapitulate LHON pathologies. The secretomes from Rot-treated iPSC-RGCs (Rot-iPSC-RGCs) were collected, and their treatment effect on human umbilical vein endothelial cells (HUVECs) was studied. Rot induced LHON-like characteristics in iPSC-RGCs, including decreased mitochondrial complex I activity and membrane potential, and increased mitochondrial reactive oxygen species (ROS) and apoptosis, leading to mitochondrial dysfunction. When HUVECs were exposed to conditioned media (CM) from Rot-iPSC-RGCs, the angiogenesis of HUVECs was suppressed compared to those treated with CM from control iPSC-RGCs (Ctrl-iPSC-RGCs). Angiogenesis-related proteins were altered in the secretomes from Rot-iPSC-RGC-derived CM, particularly angiopoietin, MMP-9, uPA, collagen XVIII, and VEGF were reduced. Notably, GeneMANIA analysis indicated that VEGFA emerged as the pivotal angiogenesis-related protein among the identified proteins secreted by health iPSC-RGCs but reduced in the secretomes from Rot-iPSC-RGCs. Quantitative real-time PCR and western blots confirmed the reduction of VEGFA at both transcription and translation levels, respectively. Our study reveals that Rot-iPSC-RGCs establish a microenvironment to diminish the angiogenic potential of vascular cells nearby, shedding light on the paracrine regulation of LHON-affected RGCs on retinal vasculature.
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Affiliation(s)
- Shih-Yuan Peng
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan, ROC
| | - Chih-Ying Chen
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan, ROC
| | - Hsin Chen
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan, ROC; Institute of Molecular Medicine, National Tsing Hua University, Hsinchu 300044, Taiwan, ROC
| | - Yi-Ping Yang
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan, ROC; Institute of Food Safety and Health Risk Assessment, School of Pharmaceutical Sciences, National Yang-Ming Chiao Tung University, Taipei 11221, Taiwan, ROC
| | - Mong-Lien Wang
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan, ROC; Institute of Food Safety and Health Risk Assessment, School of Pharmaceutical Sciences, National Yang-Ming Chiao Tung University, Taipei 11221, Taiwan, ROC
| | - Fu-Ting Tsai
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan, ROC
| | - Chian-Shiu Chien
- Institute of Physiology, National Yang Ming Chiao Tung University, Taiwan, ROC
| | - Pei-Yu Weng
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan, ROC
| | - En-Tung Tsai
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan, ROC
| | - I-Chieh Wang
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan, ROC
| | - Chih-Chien Hsu
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 112201, Taiwan, ROC
| | - Tai-Chi Lin
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 112201, Taiwan, ROC
| | - De-Kuang Hwang
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 112201, Taiwan, ROC
| | - Shih-Jen Chen
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 112201, Taiwan, ROC
| | - Shih-Hwa Chiou
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan, ROC; Institute of Pharmacology, School of Medicine, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan, ROC; Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 112201, Taiwan, ROC; Genomics Research Center, Academia Sinica, Taipei 11529, Taiwan, ROC.
| | - Chuan-Chin Chiao
- Institute of Molecular Medicine, National Tsing Hua University, Hsinchu 300044, Taiwan, ROC.
| | - Yueh Chien
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan, ROC.
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4
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Pasqualotto BA, Nelson A, Deheshi S, Sheldon CA, Vogl AW, Rintoul GL. Impaired mitochondrial morphological plasticity and failure of mitophagy associated with the G11778A mutation of LHON. Biochem Biophys Res Commun 2024; 721:150119. [PMID: 38768545 DOI: 10.1016/j.bbrc.2024.150119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 05/07/2024] [Accepted: 05/13/2024] [Indexed: 05/22/2024]
Abstract
Mitochondrial dynamics were examined in human dermal fibroblasts biopsied from a confirmed Leber's Hereditary Optic Neuropathy (LHON) patient with a homoplasmic G11778A mutation of the mitochondrial genome. Expression of the G11778A mutation did not impart any discernible difference in mitochondrial network morphology using widefield fluorescence microscopy. However, at the ultrastructural level, cells expressing this mutation exhibited an impairment of mitochondrial morphological plasticity when forced to utilize oxidative phosphorylation (OXPHOS) by transition to glucose-free, galactose-containing media. LHON fibroblasts also displayed a transient increase in mitophagy upon transition to galactose media. These results provide new insights into the consequences of the G11778A mutation of LHON and the pathological mechanisms underlying this disease.
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Affiliation(s)
- Bryce A Pasqualotto
- Centre for Cell Biology, Development, and Disease, and the Department of Biological Sciences, Simon Fraser University, Canada
| | - Alexa Nelson
- Centre for Cell Biology, Development, and Disease, and the Department of Biological Sciences, Simon Fraser University, Canada
| | - Samineh Deheshi
- Centre for Cell Biology, Development, and Disease, and the Department of Biological Sciences, Simon Fraser University, Canada
| | - Claire A Sheldon
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Canada
| | - A Wayne Vogl
- Life Sciences Institute and the Department of Cellular & Physiological Sciences, University of British Columbia, Canada
| | - Gordon L Rintoul
- Centre for Cell Biology, Development, and Disease, and the Department of Biological Sciences, Simon Fraser University, Canada.
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5
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Lambiri DW, Levin LA. Maculopapillary Bundle Degeneration in Optic Neuropathies. Curr Neurol Neurosci Rep 2024; 24:203-218. [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] [MESH Headings] [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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Dobner J, Nguyen T, Pavez-Giani MG, Cyganek L, Distelmaier F, Krutmann J, Prigione A, Rossi A. mtDNA analysis using Mitopore. Mol Ther Methods Clin Dev 2024; 32:101231. [PMID: 38572068 PMCID: PMC10988129 DOI: 10.1016/j.omtm.2024.101231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 03/08/2024] [Indexed: 04/05/2024]
Abstract
Mitochondrial DNA (mtDNA) analysis is crucial for the diagnosis of mitochondrial disorders, forensic investigations, and basic research. Existing pipelines are complex, expensive, and require specialized personnel. In many cases, including the diagnosis of detrimental single nucleotide variants (SNVs), mtDNA analysis is still carried out using Sanger sequencing. Here, we developed a simple workflow and a publicly available webserver named Mitopore that allows the detection of mtDNA SNVs, indels, and haplogroups. To simplify mtDNA analysis, we tailored our workflow to process noisy long-read sequencing data for mtDNA analysis, focusing on sequence alignment and parameter optimization. We implemented Mitopore with eliBQ (eliminate bad quality reads), an innovative quality enhancement that permits the increase of per-base quality of over 20% for low-quality data. The whole Mitopore workflow and webserver were validated using patient-derived and induced pluripotent stem cells harboring mtDNA mutations. Mitopore streamlines mtDNA analysis as an easy-to-use fast, reliable, and cost-effective analysis method for both long- and short-read sequencing data. This significantly enhances the accessibility of mtDNA analysis and reduces the cost per sample, contributing to the progress of mtDNA-related research and diagnosis.
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Affiliation(s)
- Jochen Dobner
- Institut für Umweltmedizinische Forschung (IUF)-Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
| | - Thach Nguyen
- Institut für Umweltmedizinische Forschung (IUF)-Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
| | - Mario Gustavo Pavez-Giani
- Clinic for Cardiology and Pneumology, University Medical Center Göttingen, 37075 Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, 37075 Göttingen, Germany
| | - Lukas Cyganek
- Clinic for Cardiology and Pneumology, University Medical Center Göttingen, 37075 Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, 37075 Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), University of Göttingen, 37075 Göttingen, Germany
| | - Felix Distelmaier
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, Medical Faculty, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Jean Krutmann
- Institut für Umweltmedizinische Forschung (IUF)-Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
- Medical Faculty, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Alessandro Prigione
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, Medical Faculty, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Andrea Rossi
- Institut für Umweltmedizinische Forschung (IUF)-Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
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7
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Pasqualotto BA, Tegeman C, Frame AK, McPhedrain R, Halangoda K, Sheldon CA, Rintoul GL. Galactose-replacement unmasks the biochemical consequences of the G11778A mitochondrial DNA mutation of LHON in patient-derived fibroblasts. Exp Cell Res 2024; 439:114075. [PMID: 38710404 DOI: 10.1016/j.yexcr.2024.114075] [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: 11/16/2023] [Revised: 04/30/2024] [Accepted: 05/03/2024] [Indexed: 05/08/2024]
Abstract
Leber's hereditary optic neuropathy (LHON) is a visual impairment associated with mutations of mitochondrial genes encoding elements of the electron transport chain. While much is known about the genetics of LHON, the cellular pathophysiology leading to retinal ganglion cell degeneration and subsequent vision loss is poorly understood. The impacts of the G11778A mutation of LHON on bioenergetics, redox balance and cell proliferation were examined in patient-derived fibroblasts. Replacement of glucose with galactose in the culture media reveals a deficit in the proliferation of G11778A fibroblasts, imparts a reduction in ATP biosynthesis, and a reduction in capacity to accommodate exogenous oxidative stress. While steady-state ROS levels were unaffected by the LHON mutation, cell survival was diminished in response to exogenous H2O2.
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Affiliation(s)
- Bryce A Pasqualotto
- Department of Biological Sciences and Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC, Canada
| | - Carina Tegeman
- Department of Biological Sciences and Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC, Canada
| | - Ariel K Frame
- Department of Biological Sciences and Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC, Canada
| | - Ryan McPhedrain
- Department of Biological Sciences and Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC, Canada
| | - Kolitha Halangoda
- Department of Biological Sciences and Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC, Canada
| | - Claire A Sheldon
- Dept. of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Gordon L Rintoul
- Department of Biological Sciences and Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC, Canada.
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8
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Weller SR, Burnell JE, Aho BM, Obeng B, Ledue EL, Shim JK, Hess ST, Gosse JA. Antimicrobial cetylpyridinium chloride causes functional inhibition of mitochondria as potently as canonical mitotoxicants, nanostructural disruption of mitochondria, and mitochondrial Ca 2+ efflux in living rodent and primary human cells. Food Chem Toxicol 2024; 186:114547. [PMID: 38408634 PMCID: PMC11060648 DOI: 10.1016/j.fct.2024.114547] [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: 09/12/2023] [Revised: 11/08/2023] [Accepted: 02/23/2024] [Indexed: 02/28/2024]
Abstract
People are exposed to high concentrations of antibacterial agent cetylpyridinium chloride (CPC) via food and personal care products, despite little published information regarding CPC effects on eukaryotes. Here, we show that low-micromolar CPC exposure, which does not cause cell death, inhibits mitochondrial ATP production in primary human keratinocytes, mouse NIH-3T3 fibroblasts, and rat RBL-2H3 immune mast cells. ATP inhibition via CPC (EC50 1.7 μM) is nearly as potent as that caused by canonical mitotoxicant CCCP (EC50 1.2 μM). CPC inhibition of oxygen consumption rate (OCR) tracks with that of ATP: OCR is halved due to 1.75 μM CPC in RBL-2H3 cells and 1.25 μM in primary human keratinocytes. Mitochondrial [Ca2+] changes can cause mitochondrial dysfunction. Here we show that CPC causes mitochondrial Ca2+ efflux from mast cells via an ATP-inhibition mechanism. Using super-resolution microscopy (fluorescence photoactivation localization) in live cells, we have discovered that CPC causes mitochondrial nanostructural defects in live cells within 60 min, including the formation of spherical structures with donut-like cross section. This work reveals CPC as a mitotoxicant despite widespread use, highlighting the importance of further research into its toxicological safety.
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Affiliation(s)
- Sasha R Weller
- Department of Molecular and Biomedical Sciences, 5735 Hitchner, University of Maine, Orono, ME, 04469, USA
| | - John E Burnell
- Department of Molecular and Biomedical Sciences, 5735 Hitchner, University of Maine, Orono, ME, 04469, USA
| | - Brandon M Aho
- Department of Physics and Astronomy, 5709 Bennett Hall, University of Maine, Orono, ME, 04469, USA
| | - Bright Obeng
- Department of Molecular and Biomedical Sciences, 5735 Hitchner, University of Maine, Orono, ME, 04469, USA
| | - Emily L Ledue
- Department of Molecular and Biomedical Sciences, 5735 Hitchner, University of Maine, Orono, ME, 04469, USA
| | - Juyoung K Shim
- Department of Biology, Jewett Hall, University of Maine at Augusta, Augusta, ME, 04330, USA
| | - Samuel T Hess
- Department of Physics and Astronomy, 5709 Bennett Hall, University of Maine, Orono, ME, 04469, USA.
| | - Julie A Gosse
- Department of Molecular and Biomedical Sciences, 5735 Hitchner, University of Maine, Orono, ME, 04469, USA.
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9
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Gushi S, Balis V. Mitochondrial Inherited Disorders and their Correlation with Neurodegenerative Diseases. Endocr Metab Immune Disord Drug Targets 2024; 24:381-393. [PMID: 37937560 DOI: 10.2174/0118715303250271231018103202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 07/13/2023] [Accepted: 09/15/2023] [Indexed: 11/09/2023]
Abstract
Mitochondria are essential organelles for the survival of a cell because they produce energy. The cells that need more mitochondria are neurons because they perform a variety of tasks that are necessary to support brain homeostasis. The build-up of abnormal proteins in neurons, as well as their interactions with mitochondrial proteins, or MAM proteins, cause serious health issues. As a result, mitochondrial functions, such as mitophagy, are impaired, resulting in the disorders described in this review. They are also due to mtDNA mutations, which alter the heritability of diseases. The topic of disease prevention, as well as the diagnosis, requires further explanation and exploration. Finally, there are treatments that are quite promising, but more detailed research is needed.
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Affiliation(s)
- Sofjana Gushi
- Department of Health Science and Biomedical Science, Metropolitan College - Thessaloniki Campus, Thessaloniki, Greece
| | - Vasileios Balis
- Department of Health Science and Biomedical Science, Metropolitan College - Thessaloniki Campus, Thessaloniki, Greece
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Böhm EW, Buonfiglio F, Voigt AM, Bachmann P, Safi T, Pfeiffer N, Gericke A. Oxidative stress in the eye and its role in the pathophysiology of ocular diseases. Redox Biol 2023; 68:102967. [PMID: 38006824 PMCID: PMC10701459 DOI: 10.1016/j.redox.2023.102967] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 11/10/2023] [Accepted: 11/14/2023] [Indexed: 11/27/2023] Open
Abstract
Oxidative stress occurs through an imbalance between the generation of reactive oxygen species (ROS) and the antioxidant defense mechanisms of cells. The eye is particularly exposed to oxidative stress because of its permanent exposure to light and due to several structures having high metabolic activities. The anterior part of the eye is highly exposed to ultraviolet (UV) radiation and possesses a complex antioxidant defense system to protect the retina from UV radiation. The posterior part of the eye exhibits high metabolic rates and oxygen consumption leading subsequently to a high production rate of ROS. Furthermore, inflammation, aging, genetic factors, and environmental pollution, are all elements promoting ROS generation and impairing antioxidant defense mechanisms and thereby representing risk factors leading to oxidative stress. An abnormal redox status was shown to be involved in the pathophysiology of various ocular diseases in the anterior and posterior segment of the eye. In this review, we aim to summarize the mechanisms of oxidative stress in ocular diseases to provide an updated understanding on the pathogenesis of common diseases affecting the ocular surface, the lens, the retina, and the optic nerve. Moreover, we discuss potential therapeutic approaches aimed at reducing oxidative stress in this context.
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Affiliation(s)
- Elsa Wilma Böhm
- Department of Ophthalmology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstrasse 1, 55131, Mainz, Germany.
| | - Francesco Buonfiglio
- Department of Ophthalmology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstrasse 1, 55131, Mainz, Germany
| | - Anna Maria Voigt
- Department of Ophthalmology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstrasse 1, 55131, Mainz, Germany
| | - Philipp Bachmann
- Department of Ophthalmology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstrasse 1, 55131, Mainz, Germany
| | - Tarek Safi
- Department of Ophthalmology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstrasse 1, 55131, Mainz, Germany
| | - Norbert Pfeiffer
- Department of Ophthalmology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstrasse 1, 55131, Mainz, Germany
| | - Adrian Gericke
- Department of Ophthalmology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstrasse 1, 55131, Mainz, Germany.
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Baltă G, Cristache G, Barac AD, Anton N, Barac IR. Leber's Hereditary Optic Neuropathy (LHON): Clinical Experience and Outcomes after Long-Term Idebenone Treatment. Life (Basel) 2023; 13:2000. [PMID: 37895381 PMCID: PMC10608457 DOI: 10.3390/life13102000] [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: 08/24/2023] [Revised: 09/26/2023] [Accepted: 09/28/2023] [Indexed: 10/29/2023] Open
Abstract
BACKGROUND Leber's hereditary optic neuropathy (LHON) is a rare disease. Large studies are difficult to conduct; therefore, case reports provide valuable data. Since 2015, patients have been treated with Idebenone. The aim of this paper is to share our experience with diagnosing and managing patients in different stages of LHON. METHODS We designed a case series study, including four patients undergoing genetic testing and ophthalmologic examination. Criteria for Idebenone administration and follow-up were presented. RESULTS All patients had mutation 11778G>A in MT-ND4. The first patient, an 82-year-old man, with long history of vision loss, had no indication for Idebenone. Two additional cases emerged within the same family: a 40-year-old brother and a 31-year-old sister. Both received Idebenone, with good outcomes only for the female. After a one-year regimen, they were lost to follow-up. The fourth patient, a 46-year-old man, was diagnosed in the subacute stage. Idebenone administration was deferred, allowing progression of visual field defects. After 17 months of treatment, visual improvement appeared. The treatment was continued for 36 months, with short interruptions, resulting in good outcomes. CONCLUSIONS Our study demonstrated positive results with long-term Idebenone use. Contrary to medical literature, our female patient had a favorable evolution, despite the delayed diagnosis.
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Affiliation(s)
- George Baltă
- Doctoral School, University of Medicine and Pharmacy “Carol Davila” Bucharest, 050474 Bucharest, Romania;
| | - Georgiana Cristache
- Doctoral School, University of Medicine and Pharmacy “Carol Davila” Bucharest, 050474 Bucharest, Romania;
| | - Andreea Diana Barac
- Faculty of Medicine, University of Medicine and Pharmacy “Carol Davila” Bucharest, 050474 Bucharest, Romania;
| | - Nicoleta Anton
- Department of Ophthalmology, University of Medicine and Pharmacy “Grigore T. Popa” Iasi, 700115 Iasi, Romania;
| | - Ileana Ramona Barac
- Department of Ophthalmology, University of Medicine and Pharmacy “Carol Davila” Bucharest, 050474 Bucharest, Romania;
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McDonald HM, Sadikovic B, Sheldon CA, Bursztyn LLCD. Leber Hereditary Optic Neuropathy in Southwestern Ontario: A Growing List of Mutations. Can J Neurol Sci 2023; 50:738-744. [PMID: 35892476 DOI: 10.1017/cjn.2022.279] [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] [Indexed: 11/07/2022]
Abstract
BACKGROUND Leber hereditary optic neuropathy (LHON) is a rare but bilaterally blinding disease. Three characteristic disease-causing point mutations, and other less common mutations, are most often found on the mitochondrially encoded genes of NADH-ubiquinone oxidoreductase core subunits (MT-ND). The purpose of this study is to provide an overview of LHON mutations in Southwestern Ontario and to describe the associated demographic and clinical characteristics. METHODS A retrospective genetic and clinical chart review was performed from January 2015 to 2020. Patients were identified within a mitochondrial mutation database and included if a mutation was detected on the MT-ND1, -ND4, or -ND6 genes. A clinical chart review was done on all available patients. RESULTS Forty-five of 63 patients identified had classic disease-causing mutations (6.7% m.3460G>A, 44.4% m.11778G>A, and 48.9% m.14484T>C). Several of the remaining 18 patients had rare mutations previously documented in association with LHON. Of the 14 patients with clinical charts accessible for review, 12 had symptomatic disease, and all but one had bilateral optic neuropathies. Nine patients had classic LHON mutations and 3 had possible novel mutations; 7 were males; 9 had final visual acuity ≤ 20/200 in at least one eye; and 6 of those had ≤20/400 in both eyes. CONCLUSIONS This study adds to the literature on LHON in Canada, and specifically Southwestern Ontario. The demographic and clinical data regarding LHON in this geographic location, as well as possible novel disease-causing mutations, provide important information to aid clinicians in recognizing cases of LHON that may otherwise be disregarded.
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Affiliation(s)
- Heather M McDonald
- Department of Ophthalmology, University of Western Ontario, London, Ontario, Canada
| | - Bekim Sadikovic
- Pathology and Laboratory Medicine, University of Western Ontario, London, Ontario, Canada
| | - Claire A Sheldon
- Department of Ophthalmology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Lulu L C D Bursztyn
- Department of Ophthalmology, University of Western Ontario, London, Ontario, Canada
- Centre for Neuroscience Studies, University of Western Ontario, London, Ontario, Canada
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13
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Dar GM, Ahmad E, Ali A, Mahajan B, Ashraf GM, Saluja SS. Genetic aberration analysis of mitochondrial respiratory complex I implications in the development of neurological disorders and their clinical significance. Ageing Res Rev 2023; 87:101906. [PMID: 36905963 DOI: 10.1016/j.arr.2023.101906] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 03/02/2023] [Accepted: 03/05/2023] [Indexed: 03/11/2023]
Abstract
Growing neurological diseases pose difficult challenges for modern medicine to diagnose and manage them effectively. Many neurological disorders mainly occur due to genetic alteration in genes encoding mitochondrial proteins. Moreover, mitochondrial genes exhibit a higher rate of mutation due to the generation of Reactive oxygen species (ROS) during oxidative phosphorylation operating in their vicinity. Among the different complexes of Electron transport chain (ETC), NADH: Ubiquinone oxidoreductase (Mitochondrial complex I) is the most important. This multimeric enzyme, composed of 44 subunits, is encoded by both nuclear and mitochondrial genes. It often exhibits mutations resulting in development of various neurological diseases. The most prominent diseases include leigh syndrome (LS), leber hereditary optic neuropathy (LHON), mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS), myoclonic epilepsy associated with ragged-red fibers (MERRF), idiopathic Parkinson's disease (PD) and, Alzheimer's disease (AD). Preliminary data suggest that mitochondrial complex I subunit genes mutated are frequently of nuclear origin; however, most of the mtDNA gene encoding subunits are also primarily involved. In this review, we have discussed the genetic origins of neurological disorders involving mitochondrial complex I and signified recent approaches to unravel the diagnostic and therapeutic potentials and their management.
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Affiliation(s)
- Ghulam Mehdi Dar
- Central Molecular Laboratory, Govind Ballabh Pant Institute of Postgraduate Medical Education and Research (GIPMER), New Delhi 110002, India
| | - Ejaj Ahmad
- Central Molecular Laboratory, Govind Ballabh Pant Institute of Postgraduate Medical Education and Research (GIPMER), New Delhi 110002, India
| | - Asgar Ali
- Central Molecular Laboratory, Govind Ballabh Pant Institute of Postgraduate Medical Education and Research (GIPMER), New Delhi 110002, India
| | - Bhawna Mahajan
- Department of Biochemistry, Govind Ballabh Pant Institute of Postgraduate Medical Education and Research (GIPMER), New Delhi 110002, India
| | - Ghulam Md Ashraf
- Department of Medical Laboratory Sciences, College of Health Sciences, and Sharjah Institute for Medical Research, University of Sharjah, Sharjah 27272, United Arab Emirates.
| | - Sundeep Singh Saluja
- Central Molecular Laboratory, Govind Ballabh Pant Institute of Postgraduate Medical Education and Research (GIPMER), New Delhi 110002, India; Department of GI Surgery, Govind Ballabh Pant Institute of Postgraduate Medical Education and Research (GIPMER), New Delhi 110002, India.
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Genetics of mitochondrial diseases: Current approaches for the molecular diagnosis. HANDBOOK OF CLINICAL NEUROLOGY 2023; 194:141-165. [PMID: 36813310 DOI: 10.1016/b978-0-12-821751-1.00011-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Mitochondrial diseases are a genetically and phenotypically variable set of monogenic disorders. The main characteristic of mitochondrial diseases is a defective oxidative phosphorylation. Both nuclear and mitochondrial DNA encode the approximately 1500 mitochondrial proteins. Since identification of the first mitochondrial disease gene in 1988 a total of 425 genes have been associated with mitochondrial diseases. Mitochondrial dysfunctions can be caused both by pathogenic variants in the mitochondrial DNA or the nuclear DNA. Hence, besides maternal inheritance, mitochondrial diseases can follow all modes of Mendelian inheritance. The maternal inheritance and tissue specificity distinguish molecular diagnostics of mitochondrial disorders from other rare disorders. With the advances made in the next-generation sequencing technology, whole exome sequencing and even whole-genome sequencing are now the established methods of choice for molecular diagnostics of mitochondrial diseases. They reach a diagnostic rate of more than 50% in clinically suspected mitochondrial disease patients. Moreover, next-generation sequencing is delivering a constantly growing number of novel mitochondrial disease genes. This chapter reviews mitochondrial and nuclear causes of mitochondrial diseases, molecular diagnostic methodologies, and their current challenges and perspectives.
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Ji Y, Wang L, Ding H, Tian Q, Fan K, Shi D, Yu C, Qin W. Aberrant neurovascular coupling in Leber's hereditary optic neuropathy: Evidence from a multi-model MRI analysis. Front Neurosci 2023; 16:1050772. [PMID: 36703998 PMCID: PMC9871937 DOI: 10.3389/fnins.2022.1050772] [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: 09/22/2022] [Accepted: 12/22/2022] [Indexed: 01/12/2023] Open
Abstract
The study aimed to investigate the neurovascular coupling abnormalities in Leber's hereditary optic neuropathy (LHON) and their associations with clinical manifestations. Twenty qualified acute Leber's hereditary optic neuropathy (A-LHON, disease duration ≤ 1 year), 29 chronic Leber's hereditary optic neuropathy (C-LHON, disease duration > 1 year), as well as 37 healthy controls (HCs) were recruited. The neurovascular coupling strength was quantified as the ratio between regional homogeneity (ReHo), which represents intrinsic neuronal activity and relative cerebral blood flow (CBF), representing microcirculatory blood supply. A one-way analysis of variance was used to compare intergroup differences in ReHo/CBF ratio with gender and age as co-variables. Pearson's Correlation was used to clarify the association between ReHo, CBF, and neurovascular coupling strength. Furthermore, we applied linear and exponential non-linear regression models to explore the associations among ReHo/CBF, disease duration, and neuro-ophthalmological metrics. Compared with HCs, A_LHON, and C_LHON patients demonstrated a higher ReHo/CBF ratio than the HCs in the bilateral primary visual cortex (B_CAL), which was accompanied by reduced CBF while preserved ReHo. Besides, only C_LHON had a higher ReHo/CBF ratio and reduced CBF in the left middle temporal gyrus (L_MTG) and left sensorimotor cortex (L_SMC) than the HCs, which was accompanied by increased ReHo in L_MTG (p < 1.85e-3, Bonferroni correction). A-LHON and C-LHON showed a negative Pearson correlation between ReHo/CBF ratio and CBF in B_CAL, L_SMC, and L_MTG. Only C_LHON showed a weak positive correlation between ReHo/CBF ratio and ReHo in L_SMC and L_MTG (p < 0.05, uncorrected). Finally, disease duration was positively correlated with ReHo/CBF ratio of L_SMC (Exponential: Radj2 = 0.23, p = 8.66e-4, Bonferroni correction). No statistical correlation was found between ReHo/CBF ratio and neuro-ophthalmological metrics (p > 0.05, Bonferroni correction). Brain neurovascular "dyscoupling" within and outside the visual system might be an important neurological mechanism of LHON.
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Affiliation(s)
- Yi Ji
- Tianjin Key Lab of Functional Imaging, Department of Radiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Ling Wang
- Department of Medical Imaging, Henan Provincial People’s Hospital, Zhengzhou, China
| | - Hao Ding
- Tianjin Key Lab of Functional Imaging, Department of Radiology, Tianjin Medical University General Hospital, Tianjin, China,School of Medical Imaging, Tianjin Medical University, Tianjin, China
| | - Qin Tian
- Department of Medical Imaging, Henan Provincial People’s Hospital, Zhengzhou, China
| | - Ke Fan
- Henan Eye Institute, Henan Eye Hospital, Henan Provincial People’s Hospital, Zhengzhou University People’s Hospital, Zhengzhou, China
| | - Dapeng Shi
- Department of Medical Imaging, Henan Provincial People’s Hospital, Zhengzhou, China,*Correspondence: Dapeng Shi,
| | - Chunshui Yu
- Tianjin Key Lab of Functional Imaging, Department of Radiology, Tianjin Medical University General Hospital, Tianjin, China,Chunshui Yu,
| | - Wen Qin
- Tianjin Key Lab of Functional Imaging, Department of Radiology, Tianjin Medical University General Hospital, Tianjin, China,Wen Qin,
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Das A, Imanishi Y. Drug Discovery Strategies for Inherited Retinal Degenerations. BIOLOGY 2022; 11:1338. [PMID: 36138817 PMCID: PMC9495580 DOI: 10.3390/biology11091338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 08/31/2022] [Accepted: 09/07/2022] [Indexed: 12/03/2022]
Abstract
Inherited retinal degeneration is a group of blinding disorders afflicting more than 1 in 4000 worldwide. These disorders frequently cause the death of photoreceptor cells or retinal ganglion cells. In a subset of these disorders, photoreceptor cell death is a secondary consequence of retinal pigment epithelial cell dysfunction or degeneration. This manuscript reviews current efforts in identifying targets and developing small molecule-based therapies for these devastating neuronal degenerations, for which no cures exist. Photoreceptors and retinal ganglion cells are metabolically demanding owing to their unique structures and functional properties. Modulations of metabolic pathways, which are disrupted in most inherited retinal degenerations, serve as promising therapeutic strategies. In monogenic disorders, great insights were previously obtained regarding targets associated with the defective pathways, including phototransduction, visual cycle, and mitophagy. In addition to these target-based drug discoveries, we will discuss how phenotypic screening can be harnessed to discover beneficial molecules without prior knowledge of their mechanisms of action. Because of major anatomical and biological differences, it has frequently been challenging to model human inherited retinal degeneration conditions using small animals such as rodents. Recent advances in stem cell-based techniques are opening new avenues to obtain pure populations of human retinal ganglion cells and retinal organoids with photoreceptor cells. We will discuss concurrent ideas of utilizing stem-cell-based disease models for drug discovery and preclinical development.
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Affiliation(s)
- Arupratan Das
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Yoshikazu Imanishi
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Stramkauskaitė A, Povilaityte I, Glebauskiene B, Liutkeviciene R. Clinical Overview of Leber Hereditary Optic Neuropathy. Acta Med Litu 2022; 29:9-18. [PMID: 36061944 PMCID: PMC9428633 DOI: 10.15388/amed.2022.29.1.19] [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: 03/16/2022] [Revised: 05/15/2022] [Accepted: 05/17/2022] [Indexed: 11/22/2022] Open
Abstract
Leber hereditary ptic neuropathy (LHON) is a disease of young adults with bilateral, painless, subacute visual loss. The peak age of onset of LHON is in the second and third decades of life. Men are 4 times more likely to be affected than women. In about 25-50% of cases, both eyes are affected simultaneously. In unilateral cases, the other eye is usually affected 2 to 3 months later. Visual acuity deteriorates to counting fingers or worse with a dense central or centrocecal scotoma. In the subacute phase, the optic disc may appear hyperemic with swelling of the peripapillary retinal nerve fibre layer, peripapillary telangiectasias, and increased vascular tortuosity. Ocular coherence tomography of the macula shows marked thinning of the ganglion cell complex even at this stage. The diagnosis of LHON is made in a subject with a consistent clinical history and/or one of three common pathogenic mitochondrial DNA (mtDNA) variants identified by molecular genetic testing. Idebenone was approved by the European Medicines Agency under exceptional circumstances for the treatment of LHON. Current evidence suggests some benefit to vision in a subset of affected individuals treated with idebenone, particularly when treated within the first year of onset of vision loss. In this article, we discuss aetiology, clinical features, diagnosis, differential dignosis, prognosis and treatment.
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THE INTEGRATED STRESS RESPONSE AS A KEY PATHWAY DOWNSTREAM OF MITOCHONDRIAL DYSFUNCTION. CURRENT OPINION IN PHYSIOLOGY 2022. [DOI: 10.1016/j.cophys.2022.100555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Liu Y, Bell BA, Song Y, Zhang K, Anderson B, Axelsen PH, Bohannan W, Agbaga M, Park HG, James G, Brenna JT, Schmidt K, Dunaief JL, Shchepinov MS. Deuterated docosahexaenoic acid protects against oxidative stress and geographic atrophy-like retinal degeneration in a mouse model with iron overload. Aging Cell 2022; 21:e13579. [PMID: 35257475 PMCID: PMC9009113 DOI: 10.1111/acel.13579] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/24/2022] [Accepted: 02/11/2022] [Indexed: 01/03/2023] Open
Abstract
Oxidative stress plays a central role in age-related macular degeneration (AMD). Iron, a potent generator of hydroxyl radicals through the Fenton reaction, has been implicated in AMD. One easily oxidized molecule is docosahexaenoic acid (DHA), the most abundant polyunsaturated fatty acid in photoreceptor membranes. Oxidation of DHA produces toxic oxidation products including carboxyethylpyrrole (CEP) adducts, which are increased in the retinas of AMD patients. In this study, we hypothesized that deuterium substitution on the bis-allylic sites of DHA in photoreceptor membranes could prevent iron-induced retinal degeneration by inhibiting oxidative stress and lipid peroxidation. Mice were fed with either DHA deuterated at the oxidation-prone positions (D-DHA) or control natural DHA and then given an intravitreal injection of iron or control saline. Orally administered D-DHA caused a dose-dependent increase in D-DHA levels in the neural retina and retinal pigment epithelium (RPE) as measured by mass spectrometry. At 1 week after iron injection, D-DHA provided nearly complete protection against iron-induced retinal autofluorescence and retinal degeneration, as determined by in vivo imaging, electroretinography, and histology. Iron injection resulted in carboxyethylpyrrole conjugate immunoreactivity in photoreceptors and RPE in mice fed with natural DHA but not D-DHA. Quantitative PCR results were consistent with iron-induced oxidative stress, inflammation, and retinal cell death in mice fed with natural DHA but not D-DHA. Taken together, our findings suggest that DHA oxidation is central to the pathogenesis of iron-induced retinal degeneration. They also provide preclinical evidence that dosing with D-DHA could be a viable therapeutic strategy for retinal diseases involving oxidative stress.
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Affiliation(s)
- Yingrui Liu
- F.M. Kirby Center for Molecular OphthalmologyScheie Eye InstitutePerelman School of Medicine at the University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Brent A. Bell
- F.M. Kirby Center for Molecular OphthalmologyScheie Eye InstitutePerelman School of Medicine at the University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Ying Song
- F.M. Kirby Center for Molecular OphthalmologyScheie Eye InstitutePerelman School of Medicine at the University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Kevin Zhang
- F.M. Kirby Center for Molecular OphthalmologyScheie Eye InstitutePerelman School of Medicine at the University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Brandon Anderson
- F.M. Kirby Center for Molecular OphthalmologyScheie Eye InstitutePerelman School of Medicine at the University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Paul H. Axelsen
- Department of PharmacologyPerelman School of Medicine at the University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Whitney Bohannan
- Departments of Cell Biology and OphthalmologyUniversity of Oklahoma Health Sciences Center and the Dean McGee Eye InstituteOklahoma CityOklahomaUSA
| | - Martin‐Paul Agbaga
- Departments of Cell Biology and OphthalmologyUniversity of Oklahoma Health Sciences Center and the Dean McGee Eye InstituteOklahoma CityOklahomaUSA
| | - Hui Gyu Park
- Dell Pediatric Research InstituteUniversity of Texas at AustinAustinTexasUSA
| | - Genevieve James
- Dell Pediatric Research InstituteUniversity of Texas at AustinAustinTexasUSA
| | - J. Thomas Brenna
- Dell Pediatric Research InstituteUniversity of Texas at AustinAustinTexasUSA
| | | | - Joshua L. Dunaief
- F.M. Kirby Center for Molecular OphthalmologyScheie Eye InstitutePerelman School of Medicine at the University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
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Subramaniam MD, Chirayath RB, Iyer M, Nair AP, Vellingiri B. Mesenchymal stem cells (MSCs) in Leber's hereditary optic neuropathy (LHON): a potential therapeutic approach for future. Int Ophthalmol 2022; 42:2949-2964. [PMID: 35357640 DOI: 10.1007/s10792-022-02267-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 03/12/2022] [Indexed: 12/21/2022]
Abstract
BACKGROUND Optic neuropathy has become a new typical syndromic multi-system disease that leads to optic atrophy. This review discusses potential treatments and advances of Leber's hereditary optic neuropathy (LHON), a sporadic genetic disorder. LHON is caused due to slight mutations in mitochondria leading to mitochondrial dysfunction, causing vision loss. There are no current significant treatments that have been proven to work for LHON. METHODS However, extensive review was carried out on capable studies that have shown potential treatment sensory systems and are being evaluated currently. Some of these studies are in clinical trials, whereas other ones are still being planned. Here, we focus more on treatment based on mesenchymal stem cells-mediated mitochondrial transfer via various techniques. We discuss different mitochondrial transfer modes and possible ways to understand the mitochondria transfer technique's phenotypic characteristics. CONCLUSION It is clearly understood that transfer of healthy mitochondria from MSC to target cell would regulate the range of reactive oxygen species and ATP'S, which are majorly responsible for mutation upon irregulating. Therefore, mitochondrial transfer is suggested and discussed in this review with various aspects. The graphical abstract represents different means of mitochondrial transport like (a) Tunnelling nanotubules, (b) Extracellular vesicles, (c) Cell fusion and (d) Gap junctions. In (a) Tunnelling nanotubules, the signalling pathways TNF- α/TNF αip2 and NFkB/TNF αep2 are responsible for forming tunnels. Also, Miro protein acts as cargo for the transport of mitochondria with myosin's help in the presence of RhoGTPases [35]. In (b) Extracellular vesicles, the RhoA ARF6 contributes to Actin/Cytoskeletal rearrangement leading to the shedding of microvesicles. Coming to (c) Cell fusion when there is a high amount of ATP, the cells tend to fuse when in close proximity leading to the transfer of mitochondria via EFF-1/HAP2 [48]. In (d) Gap Junctions, Connexin43 is responsible for the intracellular channel in the presence of more ATP [86].
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Affiliation(s)
- Mohana Devi Subramaniam
- SN ONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Chennai, 600 006, India.
| | - Ruth Bright Chirayath
- SN ONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Chennai, 600 006, India
| | - Mahalaxmi Iyer
- SN ONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Chennai, 600 006, India
| | - Aswathy P Nair
- SN ONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Chennai, 600 006, India
| | - Balachandar Vellingiri
- Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore, 641 046, India
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Mercuţ MF, Tănasie CA, Dan AO, Nicolcescu AM, Ică OM, Mocanu CL, Ştefănescu-Dima AŞ. Retinal morphological and functional response to Idebenone therapy in Leber hereditary optic neuropathy. ROMANIAN JOURNAL OF MORPHOLOGY AND EMBRYOLOGY = REVUE ROUMAINE DE MORPHOLOGIE ET EMBRYOLOGIE 2022; 63:213-219. [PMID: 36074687 PMCID: PMC9593130 DOI: 10.47162/rjme.63.1.24] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 08/20/2022] [Indexed: 06/01/2023]
Abstract
Leber hereditary optic neuropathy (LHON) is a mitochondrial disease leading to optic atrophy due to degeneration of the retinal ganglion cell. A curative treatment is not available at the moment, but a new antioxidant drug, Idebenone, is expected to reduce the progression of the disorder. Two male patients, genetically confirmed with LHON, were clinically, morphologically, and electrophysiologically evaluated, before and three, six, nine and 12 months after starting the treatment. The patient with 3460G>A mutation in mitochondrially-encoded nicotinamide adenine dinucleotide, reduced form (NADH):ubiquinone oxidoreductase core subunit (mtND)1 gene showed an improvement in visual acuity, visual field, and visual evoked potentials with no effect on morphological examinations, while the patient with 11778G>A mutation in mtND4 gene showed no functional, nor morphological recovery after one year of treatment. This study demonstrates that Idebenone, depending on the genetic profile of the disease, may be effective in functional improvement in patients with LHON.
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22
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Kang EYC, Liu PK, Wen YT, Quinn PMJ, Levi SR, Wang NK, Tsai RK. Role of Oxidative Stress in Ocular Diseases Associated with Retinal Ganglion Cells Degeneration. Antioxidants (Basel) 2021; 10:1948. [PMID: 34943051 PMCID: PMC8750806 DOI: 10.3390/antiox10121948] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/25/2021] [Accepted: 12/02/2021] [Indexed: 12/12/2022] Open
Abstract
Ocular diseases associated with retinal ganglion cell (RGC) degeneration is the most common neurodegenerative disorder that causes irreversible blindness worldwide. It is characterized by visual field defects and progressive optic nerve atrophy. The underlying pathophysiology and mechanisms of RGC degeneration in several ocular diseases remain largely unknown. RGCs are a population of central nervous system neurons, with their soma located in the retina and long axons that extend through the optic nerve to form distal terminals and connections in the brain. Because of this unique cytoarchitecture and highly compartmentalized energy demand, RGCs are highly mitochondrial-dependent for adenosine triphosphate (ATP) production. Recently, oxidative stress and mitochondrial dysfunction have been found to be the principal mechanisms in RGC degeneration as well as in other neurodegenerative disorders. Here, we review the role of oxidative stress in several ocular diseases associated with RGC degenerations, including glaucoma, hereditary optic atrophy, inflammatory optic neuritis, ischemic optic neuropathy, traumatic optic neuropathy, and drug toxicity. We also review experimental approaches using cell and animal models for research on the underlying mechanisms of RGC degeneration. Lastly, we discuss the application of antioxidants as a potential future therapy for the ocular diseases associated with RGC degenerations.
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Affiliation(s)
- Eugene Yu-Chuan Kang
- Department of Ophthalmology, Linkou Chang Gung Memorial Hospital, Taoyuan 33302, Taiwan;
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
| | - Pei-Kang Liu
- Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung 80424, Taiwan;
- School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80424, Taiwan
- Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Yao-Tseng Wen
- Institute of Eye Research, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien 97403, Taiwan;
| | - Peter M. J. Quinn
- Jonas Children’s Vision Care, and Bernard and Shirlee Brown Glaucoma Laboratory, Columbia Stem Cell Initiative, Departments of Ophthalmology, Pathology and Cell Biology, Institute of Human Nutrition, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; (P.M.J.Q.); (S.R.L.)
| | - Sarah R. Levi
- Jonas Children’s Vision Care, and Bernard and Shirlee Brown Glaucoma Laboratory, Columbia Stem Cell Initiative, Departments of Ophthalmology, Pathology and Cell Biology, Institute of Human Nutrition, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; (P.M.J.Q.); (S.R.L.)
| | - Nan-Kai Wang
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Rong-Kung Tsai
- Institute of Eye Research, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien 97403, Taiwan;
- Institute of Medical Sciences, Tzu Chi University, Hualien 97403, Taiwan
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23
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Villarejo-Zori B, Jiménez-Loygorri JI, Zapata-Muñoz J, Bell K, Boya P. New insights into the role of autophagy in retinal and eye diseases. Mol Aspects Med 2021; 82:101038. [PMID: 34620506 DOI: 10.1016/j.mam.2021.101038] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 09/12/2021] [Accepted: 09/27/2021] [Indexed: 02/06/2023]
Abstract
Autophagy is a fundamental homeostatic pathway that mediates the degradation and recycling of intracellular components. It serves as a key quality control mechanism, especially in non-dividing cells such as neurons. Proteins, lipids, and even whole organelles are engulfed in autophagosomes and delivered to the lysosome for elimination. The retina is a light-sensitive tissue located in the back of the eye that detects and processes visual images. Vision is a highly demanding process, making the eye one of the most metabolically active tissues in the body and photoreceptors display glycolytic metabolism, even in the presence of oxygen. The retina and eye are also exposed to other stressors that can impair their function, including genetic mutations and age-associated changes. Autophagy, among other pathways, is therefore a key process for the preservation of retinal homeostasis. Here, we review the roles of both canonical and non-canonical autophagy in normal retinal function. We discuss the most recent studies investigating the participation of autophagy in eye diseases such as age-related macular degeneration, glaucoma, and diabetic retinopathy and its role protecting photoreceptors in several forms of retinal degeneration. Finally, we consider the therapeutic potential of strategies that target autophagy pathways to treat prevalent retinal and eye diseases.
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Affiliation(s)
- Beatriz Villarejo-Zori
- Department of Cellular and Molecular Biology, Margarita Salas Center for Biological Research, CSIC, Ramiro de Maetzu, 9, 28040, Madrid, Spain
| | - Juan Ignacio Jiménez-Loygorri
- Department of Cellular and Molecular Biology, Margarita Salas Center for Biological Research, CSIC, Ramiro de Maetzu, 9, 28040, Madrid, Spain
| | - Juan Zapata-Muñoz
- Department of Cellular and Molecular Biology, Margarita Salas Center for Biological Research, CSIC, Ramiro de Maetzu, 9, 28040, Madrid, Spain
| | - Katharina Bell
- Singapore Eye Research Institute, Singapore National Eye Centre, Republic of Singapore
| | - Patricia Boya
- Department of Cellular and Molecular Biology, Margarita Salas Center for Biological Research, CSIC, Ramiro de Maetzu, 9, 28040, Madrid, Spain.
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24
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Shughoury A, Ciulla TA, Bakall B, Pennesi ME, Kiss S, Cunningham ET. Genes and Gene Therapy in Inherited Retinal Disease. Int Ophthalmol Clin 2021; 61:3-45. [PMID: 34584043 DOI: 10.1097/iio.0000000000000377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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25
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O'Neill EK, Smith R. Visual electrophysiology in the assessment of toxicity and deficiency states affecting the visual system. Eye (Lond) 2021; 35:2344-2353. [PMID: 34290445 PMCID: PMC8377028 DOI: 10.1038/s41433-021-01663-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 06/17/2021] [Accepted: 06/21/2021] [Indexed: 02/07/2023] Open
Abstract
Visual disturbance or visual failure due to toxicity of an ingested substance or a severe nutritional deficiency can present significant challenges for diagnosis and management, for instance, where an adverse reaction to a prescribed medicine is suspected. Objective assessment of visual function is important, particularly where structural changes in the retina or optic nerve have not yet occurred, as there may be a window of opportunity to mitigate or reverse visual loss. This paper reviews a number of clinical presentations where visual electrophysiological assessment has an important role in early diagnosis or management alongside clinical assessment and ocular imaging modalities. We highlight the importance of vitamin A deficiency as an easily detected marker for severe combined micronutrient deficiency.
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Affiliation(s)
- Emily K O'Neill
- Clinical and Academic Department of Ophthalmology, Great Ormond Street Hospital for Children, London, UK. Emily.O'
| | - Richard Smith
- Eye Department, Stoke Mandeville Hospital, Aylesbury, Buckinghamshire, UK.
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26
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Yang TC, Yarmishyn AA, Yang YP, Lu PC, Chou SJ, Wang ML, Lin TC, Hwang DK, Chou YB, Chen SJ, Yu WK, Wang AG, Hsu CC, Chiou SH. Mitochondrial transport mediates survival of retinal ganglion cells in affected LHON patients. Hum Mol Genet 2021; 29:1454-1464. [PMID: 32277753 DOI: 10.1093/hmg/ddaa063] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 03/02/2020] [Accepted: 03/30/2020] [Indexed: 01/17/2023] Open
Abstract
The mutations in the genes encoding the subunits of complex I of the mitochondrial electron transport chain are the most common cause of Leber's hereditary optic neuropathy (LHON), a maternal hereditary disease characterized by retinal ganglion cell (RGC) degeneration. The characteristics of incomplete penetrance indicate that nuclear genetic and environmental factors also determine phenotypic expression of LHON. Therefore, further understanding of the role of mutant mitochondrial nicotinamide adenine dinucleotide dehydrogenase subunit proteins and nuclear genetic factors/environmental effects in the etiology of LHON is needed. In this study, we generated human-induced pluripotent stem cells (hiPSCs) from healthy control, unaffected LHON mutation carrier, and affected LHON patient. hiPSC-derived RGCs were used to study the differences between affected and unaffected carriers of mitochondrial DNA point mutation m.11778G > A in the MT-ND4 gene. We found that both mutated cell lines were characterized by increase in reactive oxygen species production, however, only affected cell line had increased levels of apoptotic cells. We found a significant increase in retrograde mitochondria and a decrease in stationary mitochondria in the affected RGC axons. In addition, the messenger RNA and protein levels of KIF5A in the LHON-affected RGCs were significantly reduced. Antioxidant N-acetyl-L-cysteine could restore the expression of KIF5A and the normal pattern of mitochondrial movement in the affected RGCs. To conclude, we found essential differences in the mutually dependent processes of oxidative stress, mitochondrial transport and apoptosis between two LHON-specific mutation carrier RGC cell lines, asymptomatic carrier and disease-affected, and identified KIF5A as a central modulator of these differences.
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Affiliation(s)
- Tien-Chun Yang
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | | | - Yi-Ping Yang
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan.,School of Pharmaceutical Sciences, National Yang-Ming University, Taipei 11221, Taiwan.,School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan
| | - Pin-Chen Lu
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - Shih-Jie Chou
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan.,Institute of Pharmacology, National Yang-Ming University, Taipei 11221, Taiwan
| | - Mong-Lien Wang
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan.,School of Pharmaceutical Sciences, National Yang-Ming University, Taipei 11221, Taiwan.,School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan.,Institute of Pharmacology, National Yang-Ming University, Taipei 11221, Taiwan
| | - Tai-Chi Lin
- School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan.,Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - De-Kuang Hwang
- School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan.,Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - Yu-Bai Chou
- School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan.,Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - Shih-Jen Chen
- School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan.,Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - Wei-Kuang Yu
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - An-Guor Wang
- School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan.,Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - Chih-Chien Hsu
- School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan.,Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - Shih-Hwa Chiou
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan.,School of Pharmaceutical Sciences, National Yang-Ming University, Taipei 11221, Taiwan.,Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan
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27
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Saruta W, Shibahara I, Handa H, Inukai M, Kanayama S, Yasumoto R, Sakurai K, Akiyama H, Ishikawa H, Sato S, Hide T, Kumabe T. Leber’s hereditary optic neuropathy with diffuse white matter changes mimicking gliomatosis cerebri: illustrative case. JOURNAL OF NEUROSURGERY: CASE LESSONS 2021; 1:CASE21161. [PMID: 35854899 PMCID: PMC9245756 DOI: 10.3171/case21161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 05/12/2021] [Indexed: 11/06/2022]
Abstract
BACKGROUIND
Leber’s hereditary optic neuropathy (LHON) is a mitochondrial disease characterized by bilateral severe subacute central vision loss and a mutation in the mitochondrial DNA (mtDNA). The findings on cranial magnetic resonance imaging of patients with LHON vary from subtle to multiple white matter changes. However, they rarely present with diffuse infiltrative white matter changes.
OBSERVATIONS
The authors reported a case with diffuse white matter changes mimicking gliomatosis cerebri (GC). The histological findings included only mild glial hyperplasia without immunohistochemical positivity, supporting the diagnosis of glial tumors. Analysis of mtDNA obtained from the blood and brain tissue revealed mutation of m.11778G>A in the NADH dehydrogenase 4 gene, which confirmed the case as LHON. Immunohistochemistry of the brain tissue revealed 8-hydroxy-2′-deoxyguanosine positivity, suggesting the presence of oxidative stress.
LESSONS
LHON is extremely difficult to diagnose unless one suspects or knows the disease. The present case brings attention not only to LHON but also to other mtDNA-mutated diseases that need to be considered with diffuse white matter changes or GC.
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Affiliation(s)
| | | | | | | | - Shunsuke Kanayama
- Ophthalmology, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Ryoma Yasumoto
- Department of Clinical Laboratory, Kitasato University Hospital, Sagamihara, Kanagawa, Japan; and
| | - Keizo Sakurai
- Department of Clinical Laboratory, Kitasato University Hospital, Sagamihara, Kanagawa, Japan; and
| | - Hisanao Akiyama
- Department of Neurology, St. Marianna University School of Medicine, Kawasaki, Kanagawa, Japan
| | - Hitoshi Ishikawa
- Ophthalmology, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
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28
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Peron C, Maresca A, Cavaliere A, Iannielli A, Broccoli V, Carelli V, Di Meo I, Tiranti V. Exploiting hiPSCs in Leber's Hereditary Optic Neuropathy (LHON): Present Achievements and Future Perspectives. Front Neurol 2021; 12:648916. [PMID: 34168607 PMCID: PMC8217617 DOI: 10.3389/fneur.2021.648916] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Accepted: 04/26/2021] [Indexed: 01/19/2023] Open
Abstract
More than 30 years after discovering Leber's hereditary optic neuropathy (LHON) as the first maternally inherited disease associated with homoplasmic mtDNA mutations, we still struggle to achieve effective therapies. LHON is characterized by selective degeneration of retinal ganglion cells (RGCs) and is the most frequent mitochondrial disease, which leads young people to blindness, in particular males. Despite that causative mutations are present in all tissues, only a specific cell type is affected. Our deep understanding of the pathogenic mechanisms in LHON is hampered by the lack of appropriate models since investigations have been traditionally performed in non-neuronal cells. Effective in-vitro models of LHON are now emerging, casting promise to speed our understanding of pathophysiology and test therapeutic strategies to accelerate translation into clinic. We here review the potentials of these new models and their impact on the future of LHON patients.
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Affiliation(s)
- Camille Peron
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Alessandra Maresca
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy
| | - Andrea Cavaliere
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Angelo Iannielli
- San Raffaele Scientific Institute, Milan, Italy.,National Research Council (CNR), Institute of Neuroscience, Milan, Italy
| | - Vania Broccoli
- San Raffaele Scientific Institute, Milan, Italy.,National Research Council (CNR), Institute of Neuroscience, Milan, Italy
| | - Valerio Carelli
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy.,Department of Biomedical and Neuromotor Sciences-DIBINEM, University of Bologna, Bologna, Italy
| | - Ivano Di Meo
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Valeria Tiranti
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
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29
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Sun CB, Bai HX, Xu DN, Xiao Q, Liu Z. Mitochondrial 13513G>A Mutation With Low Mutant Load Presenting as Isolated Leber's Hereditary Optic Neuropathy Assessed by Next Generation Sequencing. Front Neurol 2021; 12:601307. [PMID: 33746872 PMCID: PMC7970004 DOI: 10.3389/fneur.2021.601307] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 02/10/2021] [Indexed: 11/13/2022] Open
Abstract
Objective: Mitochondrial 13513G>A mutation presenting as isolated Leber's hereditary optic neuropathy (LHON) without any extraocular pathology has not been reported in literature. We herein evaluate the clinical characteristics and heteroplasmy of m.13513G>A mutation manifesting as isolated LHON. Methods: Seven members of a Chinese family were enrolled in this study. All subjects underwent detailed systemic and ophthalmic examinations. Mitochondrial DNA in their blood was assessed by targeted PCR amplifications, next generation sequencing (NGS), and pyrosequencing. One hundred of blood samples from ethnic-matched healthy volunteers were tested by NGS and pyrosequencing as normal controls. Results: Isolated LHON without any other ocular or extraocular pathology was identified in a 16 year old patient in this family. Heteroplasmic m.13513G>A mutation was detected by NGS of the full mtDNA genome in the patient with mutant load of 33.56%, and of 26% 3 months and 3 years after the onset of LHON, respectively. No m.13513G>A mutation was detected in all his relatives by NGS. Pyrosequencing revealed the mutant load of m.13513G>A mutation of the LHON patient, his mother, father and sister were 22.4, 1.9, 0, and 0%, respectively. None of 100 healthy control subjects was detected to harbor m.13513G>A mutation either by NGS or by pyrosequencing of the full mt DNA genome. Conclusions: We first report m.13513G>A mutation with low mutant load presenting as isolated LHON. NGS of the full mitochondrial DNA genome is highly recommended for LHON suspects when targeted PCR amplification for main primary point mutations of LHON was negative.
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Affiliation(s)
- Chuan-bin Sun
- Eye Center, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Hai-xia Bai
- Eye Center, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Dan-ni Xu
- Eye Center, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Qing Xiao
- Eye Center, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Zhe Liu
- Department of Ophthalmology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, China
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30
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Ng WSV, Trigano M, Freeman T, Varrichio C, Kandaswamy DK, Newland B, Brancale A, Rozanowska M, Votruba M. New avenues for therapy in mitochondrial optic neuropathies. THERAPEUTIC ADVANCES IN RARE DISEASE 2021; 2:26330040211029037. [PMID: 37181108 PMCID: PMC10032437 DOI: 10.1177/26330040211029037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 06/10/2021] [Indexed: 05/16/2023]
Abstract
Mitochondrial optic neuropathies are a group of optic nerve atrophies exemplified by the two commonest conditions in this group, autosomal dominant optic atrophy (ADOA) and Leber's hereditary optic neuropathy (LHON). Their clinical features comprise reduced visual acuity, colour vision deficits, centro-caecal scotomas and optic disc pallor with thinning of the retinal nerve fibre layer. The primary aetiology is genetic, with underlying nuclear or mitochondrial gene mutations. The primary pathology is owing to retinal ganglion cell dysfunction and degeneration. There is currently only one approved treatment and no curative therapy is available. In this review we summarise the genetic and clinical features of ADOA and LHON and then examine what new avenues there may be for therapeutic intervention. The therapeutic strategies to manage LHON and ADOA can be split into four categories: prevention, compensation, replacement and repair. Prevention is technically an option by modifying risk factors such as smoking cessation, or by utilising pre-implantation genetic diagnosis, although this is unlikely to be applied in mitochondrial optic neuropathies due to the non-life threatening and variable nature of these conditions. Compensation involves pharmacological interventions that ameliorate the mitochondrial dysfunction at a cellular and tissue level. Replacement and repair are exciting new emerging areas. Clinical trials, both published and underway, in this area are likely to reveal future potential benefits, since new therapies are desperately needed. Plain language summary Optic nerve damage leading to loss of vision can be caused by a variety of insults. One group of conditions leading to optic nerve damage is caused by defects in genes that are essential for cells to make energy in small organelles called mitochondria. These conditions are known as mitochondrial optic neuropathies and two predominant examples are called autosomal dominant optic atrophy and Leber's hereditary optic neuropathy. Both conditions are caused by problems with the energy powerhouse of cells: mitochondria. The cells that are most vulnerable to this mitochondrial malfunction are called retinal ganglion cells, otherwise collectively known as the optic nerve, and they take the electrical impulse from the retina in the eye to the brain. The malfunction leads to death of some of the optic nerve cells, the degree of vision loss being linked to the number of those cells which are impacted in this way. Patients will lose visual acuity and colour vision and develop a central blind spot in their field of vision. There is currently no cure and very few treatment options. New treatments are desperately needed for patients affected by these devastating diseases. New treatments can potentially arise in four ways: prevention, compensation, replacement and repair of the defects. Here we explore how present and possible future treatments might provide hope for those suffering from these conditions.
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Affiliation(s)
| | - Matthieu Trigano
- Mitochondria and Vision Lab, School of
Optometry and Vision Sciences, Cardiff University, Cardiff, UK
| | - Thomas Freeman
- Mitochondria and Vision Lab, School of
Optometry and Vision Sciences, Cardiff University, Cardiff, UK
| | - Carmine Varrichio
- School of Pharmacy and Pharmaceutical Sciences,
Cardiff University, Cardiff, UK
| | - Dinesh Kumar Kandaswamy
- Mitochondria and Vision Lab, School of
Optometry and Vision Sciences, Cardiff University, Cardiff, UK
| | - Ben Newland
- School of Pharmacy and Pharmaceutical Sciences,
Cardiff University, Cardiff, UK
| | - Andrea Brancale
- School of Pharmacy and Pharmaceutical Sciences,
Cardiff University, Cardiff, UK
| | - Malgorzata Rozanowska
- Mitochondria and Vision Lab, School of
Optometry and Vision Sciences, Cardiff University, Cardiff, UK
| | - Marcela Votruba
- School of Optometry and Vision Sciences,
Cardiff University, Maindy Road, Cardiff, CF24 4HQ, Wales, UK; Cardiff Eye
Unit, University Hospital of Wales, Cardiff, UK
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31
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Holody C, Anfray A, Mast H, Lessard M, Han WH, Carpenter R, Bourque S, Sauvé Y, Lemieux H. Differences in relative capacities of oxidative phosphorylation pathways may explain sex- and tissue-specific susceptibility to vision defects due to mitochondrial dysfunction. Mitochondrion 2020; 56:102-110. [PMID: 33271347 DOI: 10.1016/j.mito.2020.11.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 10/09/2020] [Accepted: 11/18/2020] [Indexed: 01/03/2023]
Abstract
Mitochondrial dysfunction is a major cause and/or contributor to the development and progression of vision defects in many ophthalmologic and mitochondrial diseases. Despite their mechanistic commonality, these diseases exhibit an impressive variety in sex- and tissue-specific penetrance, incidence, and severity. Currently, there is no functional explanation for these differences. We measured the function, relative capacities, and patterns of control of various oxidative phosphorylation pathways in the retina, the eyecup, the extraocular muscles, the optic nerve, and the sciatic nerve of adult male and female rats. We show that the control of mitochondrial respiratory pathways in the visual system is sex- and tissue-specific and that this may be an important factor in determining susceptibility to mitochondrial dysfunction between these groups. The optic nerve showed a low relative capacity of the NADH pathway, depending on complex I, compared to other tissues relying mainly on mitochondria for energy production. Furthermore, NADH pathway capacity is higher in females compared to males, and this sexual dimorphism occurs only in the optic nerve. Our results propose an explanation for Leber's hereditary optic neuropathy, a mitochondrial disease more prevalent in males where the principal tissue affected is the optic nerve. To our knowledge, this is the first study to identify and provide functional explanations for differences in the occurrence and severity of visual defects between tissues and between sexes. Our results highlight the importance of considering sex- and tissue-specific mitochondrial function in elucidating pathophysiological mechanisms of visual defects.
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Affiliation(s)
- Claudia Holody
- Faculty Saint-Jean, University of Alberta, Edmonton, Alberta, Canada; Dept. of Pediatrics, University of Alberta, Edmonton, Alberta, Canada; Women and Children Research Health Institute, University of Alberta, Edmonton, Alberta, Canada; Dept. of Anesthesiology & Pain Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Anaïs Anfray
- Faculty Saint-Jean, University of Alberta, Edmonton, Alberta, Canada
| | - Heather Mast
- Faculty Saint-Jean, University of Alberta, Edmonton, Alberta, Canada
| | - Martin Lessard
- Faculty Saint-Jean, University of Alberta, Edmonton, Alberta, Canada
| | - Woo Hyun Han
- Faculty Saint-Jean, University of Alberta, Edmonton, Alberta, Canada
| | - Rowan Carpenter
- Faculty Saint-Jean, University of Alberta, Edmonton, Alberta, Canada
| | - Stephane Bourque
- Dept. of Pediatrics, University of Alberta, Edmonton, Alberta, Canada; Women and Children Research Health Institute, University of Alberta, Edmonton, Alberta, Canada; Dept. of Anesthesiology & Pain Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Yves Sauvé
- Dept. of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Hélène Lemieux
- Faculty Saint-Jean, University of Alberta, Edmonton, Alberta, Canada; Women and Children Research Health Institute, University of Alberta, Edmonton, Alberta, Canada; Dept. of Medicine, University of Alberta, Edmonton, Alberta, Canada.
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32
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Peralta S, Pinto M, Arguello T, Garcia S, Diaz F, Moraes CT. Metformin delays neurological symptom onset in a mouse model of neuronal complex I deficiency. JCI Insight 2020; 5:141183. [PMID: 33148885 PMCID: PMC7710273 DOI: 10.1172/jci.insight.141183] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 09/21/2020] [Indexed: 12/24/2022] Open
Abstract
Complex I (also known as NADH-ubiquinone oxidoreductase) deficiency is the most frequent mitochondrial disorder present in childhood. NADH-ubiquinone oxidoreductase iron-sulfur protein 3 (NDUFS3) is a catalytic subunit of the mitochondrial complex I; NDUFS3 is conserved from bacteria and essential for complex I function. Mutations affecting complex I, including in the Ndufs3 gene, cause fatal neurodegenerative diseases, such as Leigh syndrome. No treatment is available for these conditions. We developed and performed a detailed molecular characterization of a neuron-specific Ndufs3 conditional KO mouse model. We showed that deletion of Ndufs3 in forebrain neurons reduced complex I activity, altered brain energy metabolism, and increased locomotor activity with impaired motor coordination, balance, and stereotyped behavior. Metabolomics analyses showed an increase of glycolysis intermediates, suggesting an adaptive response to the complex I defect. Administration of metformin to these mice delayed the onset of the neurological symptoms but not of neuronal loss. This improvement was likely related to enhancement of glucose uptake and utilization, which are known effects of metformin in the brain. Despite reports that metformin inhibits complex I activity, our findings did not show worsening a complex I defect nor increases in lactic acid, suggesting that metformin should be further evaluated for use in patients with mitochondrial encephalopathies. Metformin delays onset of mitochondrial encephalopathy in a CNS model of mitochondrial oxidative phosphorylation defect.
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Affiliation(s)
| | | | | | | | | | - Carlos T Moraes
- Department of Neurology and.,Department of Cell Biology, Miller School of Medicine, University of Miami, Miami, Florida, USA
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Rovcanin B, Jancic J, Pajic J, Rovcanin M, Samardzic J, Djuric V, Nikolic B, Ivancevic N, Novakovic I, Kostic V. Oxidative Stress Profile in Genetically Confirmed Cases of Leber's Hereditary Optic Neuropathy. J Mol Neurosci 2020; 71:1070-1081. [PMID: 33095398 DOI: 10.1007/s12031-020-01729-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 10/06/2020] [Indexed: 10/23/2022]
Abstract
The mechanisms of the complex pathophysiology of Leber's hereditary optic neuropathy (LHON) are still insufficiently clarified. The role of oxidative stress as an etiological factor has been proposed and demonstrated in vitro, but without conclusive data that rely on clinical samples. The aim of the study was to evaluate and characterize the existence of oxidative stress in the plasma of LHON patients and healthy individuals. Whole mitochondrial genome sequencing has been performed in order to identify primary LHON mutations. For the assessment of oxidative stress, the following biomarkers were determined in plasma: total oxidant status (TOS), total antioxidant status (TAS), and oxidative stress index (OSI), while oxidative damage of cellular proteins was estimated by quantifying advanced oxidation protein products (AOPP). All three primary LHON mutations (m.3460G > A, m.11778G > A and m.14484 T > C) were identified as a genetic cause of the disease, where the most prevalent one was m.11778G > A. LHON patients have a highly significant increase of TOS and a marked decrease of TAS levels, which suggests the existence of substantial oxidative stress. OSI is high in LHON patients, which definitely implies the presence of redox imbalance. Elevated level of AOPP in LHON patients refers to the significant deleterious effects of oxidative stress on cellular proteins. Oxidative stress parameters do not significantly differ between LHON individuals with different primary mutations. Both symptomatic and asymptomatic LHON patients have an augmented level of oxidative stress which suggests that primary mutations exhibit a pro-oxidative phenotype. Gender and smoking habit significantly influence examined biochemical parameters when LHON patients are compared with the control group. Different mitochondrial haplogroups are characterized by altered levels of OSI in LHON group. The absence of physiological correlations between redox parameters reflects the deregulation of homeostatic oxidative/antioxidative balance in LHON patients. This is the greatest series of LHON patients that were evaluated for oxidative stress and the first case-controlled study that evaluated TOS, TAS, OSI, and AOPP and their influence on disease phenotype. It is evident that the presence of oxidative stress represents an important pathophysiological event in LHON and that it could potentially serve as a circulatory biomarker for a therapy efficacy understanding.
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Affiliation(s)
- Branislav Rovcanin
- Center for Endocrine Surgery, Clinical Center of Serbia, Faculty of Medicine, University of Belgrade, Koste Todorovica 8, 11000, Belgrade, Serbia. .,Center for Endocrine Surgery, Clinical Center of Serbia, Faculty of Medicine, University of Belgrade, Koste Todorovica 8, 11000, Belgrade, Serbia.
| | - Jasna Jancic
- Center for Endocrine Surgery, Clinical Center of Serbia, Faculty of Medicine, University of Belgrade, Koste Todorovica 8, 11000, Belgrade, Serbia.,Center for Endocrine Surgery, Clinical Center of Serbia, Faculty of Medicine, University of Belgrade, Koste Todorovica 8, 11000, Belgrade, Serbia.,Clinic of Neurology and Psychiatry for Children and Youth, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Jelena Pajic
- Radiation Protection Department, Radiation Protection Center, Serbian Institute of Occupational Health Dr Dragomir Karajovic, Belgrade, Serbia
| | - Marija Rovcanin
- The Obstetrics and Gynecology Clinic Narodni Front, Belgrade, Serbia
| | - Janko Samardzic
- Institute of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Vesna Djuric
- Clinic of Neurology and Psychiatry for Children and Youth, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Blazo Nikolic
- Clinic of Neurology and Psychiatry for Children and Youth, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Nikola Ivancevic
- Clinic of Neurology and Psychiatry for Children and Youth, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Ivana Novakovic
- Faculty of Medicine, Institute for Human Genetics, University of Belgrade, Belgrade, Serbia
| | - Vladimir Kostic
- Clinic of Neurology, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
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Progressive optic atrophy in a retinal ganglion cell-specific mouse model of complex I deficiency. Sci Rep 2020; 10:16326. [PMID: 33004958 PMCID: PMC7529752 DOI: 10.1038/s41598-020-73353-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 09/16/2020] [Indexed: 02/06/2023] Open
Abstract
Optic atrophy resulting from retinal ganglion cell (RGC) degeneration is a prominent ocular manifestation of mitochondrial dysfunction. Although transgenic mice lacking the mitochondrial complex I accessory subunit NDUFS4 develop early-onset optic atrophy, severe systemic mitochondrial dysfunction leads to very early death and makes this mouse line impractical for studying the pathobiology of mitochondrial optic neuropathies. Theoretically, RGC-specific inactivation of ndufs4 would allow characterization of RGC degeneration over a longer time course, provided that RGC death from mitochondrial dysfunction is a cell-autonomous process. We demonstrate that the vesicular glutamate transporter VGLUT2 may be exploited to drive robust Cre recombinase expression in RGCs without any expression observed in directly neighboring retinal cell types. Deletion of ndufs4 in RGCs resulted in reduced expression of NDUFS4 protein within the optic nerves of Vglut2-Cre;ndufs4loxP/loxP mice. RGC degeneration in Vglut2-Cre;ndufs4loxP/loxP retinas commenced around postnatal day 45 (P45) and progressed to loss of two-thirds of RGCs by P90, confirming that intrinsic complex I dysfunction is sufficient to induce RGC death. The rapidly-developing optic atrophy makes the Vglut2-Cre;ndufs4loxP/loxP mouse line a promising preclinical model for testing therapies for currently untreatable mitochondrial optic neuropathies such as Leber Hereditary Optic Neuropathy.
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Kumar A, Dhiman D, Shaha C. Sestrins: Darkhorse in the regulation of mitochondrial health and metabolism. Mol Biol Rep 2020; 47:8049-8060. [DOI: 10.1007/s11033-020-05769-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 08/28/2020] [Indexed: 12/13/2022]
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Whole Mitochondrial Genome Analysis in Serbian Cases of Leber's Hereditary Optic Neuropathy. Genes (Basel) 2020; 11:genes11091037. [PMID: 32887465 PMCID: PMC7565519 DOI: 10.3390/genes11091037] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 08/19/2020] [Accepted: 08/31/2020] [Indexed: 12/14/2022] Open
Abstract
Leber’s hereditary optic neuropathy (LHON) is a maternally inherited disorder that affects central vision in young adults and is typically associated with mitochondrial DNA (mtDNA) mutations. This study is based on a mutational screening of entire mtDNA in eight Serbian probands clinically and genetically diagnosed with LHON and four of their family members, who are asymptomatic mutation carriers. All obtained sequence variants were compared to human mtDNA databases, and their potential pathogenic characteristics were assessed by bioinformatics tools. Mitochondrial haplogroup analysis was performed by MITOMASTER. Our study revealed two well-known primary LHON mutations, m.11778G>A and m.3460G>A, and one rare LHON mutation, m.8836A>G. Various secondary mutations were detected in association with the primary mutations. MITOMASTER analysis showed that the two well-known primary mutations belong to the R haplogroup, while the rare LHON m.8836A>G was detected within the N1b haplogroup. Our results support the need for further studies of genetic background and its role in the penetrance and severity of LHON.
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Pleiotropic Mitochondria: The Influence of Mitochondria on Neuronal Development and Disease. J Neurosci 2020; 39:8200-8208. [PMID: 31619488 DOI: 10.1523/jneurosci.1157-19.2019] [Citation(s) in RCA: 119] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/09/2019] [Accepted: 08/10/2019] [Indexed: 02/08/2023] Open
Abstract
Mitochondria play many important biological roles, including ATP production, lipid biogenesis, ROS regulation, and calcium clearance. In neurons, the mitochondrion is an essential organelle for metabolism and calcium homeostasis. Moreover, mitochondria are extremely dynamic and able to divide, fuse, and move along microtubule tracks to ensure their distribution to the neuronal periphery. Mitochondrial dysfunction and altered mitochondrial dynamics are observed in a wide range of conditions, from impaired neuronal development to various neurodegenerative diseases. Novel imaging techniques and genetic tools provide unprecedented access to the physiological roles of mitochondria by visualizing mitochondrial trafficking, morphological dynamics, ATP generation, and ultrastructure. Recent studies using these new techniques have unveiled the influence of mitochondria on axon branching, synaptic function, calcium regulation with the ER, glial cell function, neurogenesis, and neuronal repair. This review provides an overview of the crucial roles played by mitochondria in the CNS in physiological and pathophysiological conditions.
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Ji Y, Zhang J, Yu J, Wang Y, Lu Y, Liang M, Li Q, Jin X, Wei Y, Meng F, Gao Y, Cang X, Tong Y, Liu X, Zhang M, Jiang P, Zhu T, Mo JQ, Huang T, Jiang P, Guan MX. Contribution of mitochondrial ND1 3394T>C mutation to the phenotypic manifestation of Leber's hereditary optic neuropathy. Hum Mol Genet 2020; 28:1515-1529. [PMID: 30597069 DOI: 10.1093/hmg/ddy450] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Revised: 11/05/2018] [Accepted: 12/22/2018] [Indexed: 11/14/2022] Open
Abstract
Mitochondrial DNA (mtDNA) mutations have been associated with Leber's hereditary optic neuropathy (LHON) and their pathophysiology remains poorly understood. In this study, we investigated the pathophysiology of a LHON susceptibility allele (m.3394T>C, p.30Y>H) in the Mitochondrial (MT)-ND1 gene. The incidence of m.3394T>C mutation was 2.7% in the cohort of 1741 probands with LHON. Extremely low penetrances of LHON were observed in 26 pedigrees carrying only m.3394T>C mutation, while 21 families bearing m.3394T>C, together with m.11778G>A or m.14484T>C mutation, exhibited higher penetrance of LHON than those in families carrying single mtDNA mutation(s). The m.3394T>C mutation disrupted the specific electrostatic interactions between Y30 of p.MT-ND1 with the sidechain of E4 and backbone carbonyl group of M1 of NDUFA1 (NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 1) of complex I, thereby altering the structure and function of complex I. We demonstrated that these cybrids bearing only m.3394T>C mutation caused mild mitochondrial dysfunctions and those harboring both m.3394T>C and m.11778G>A mutations exhibited greater mitochondrial dysfunctions than cybrids carrying only m.11778G>A mutation. In particular, the m.3394T>C mutation altered the stability of p.MT-ND1 and complex I assembly. Furthermore, the m.3394T>C mutation decreased the activities of mitochondrial complexes I, diminished mitochondrial ATP levels and membrane potential and increased the production of reactive oxygen species in the cybrids. These m.3394T>C mutation-induced alterations aggravated mitochondrial dysfunctions associated with the m.11778G>A mutation. These resultant biochemical defects contributed to higher penetrance of LHON in these families carrying both mtDNA mutations. Our findings provide new insights into the pathophysiology of LHON arising from the synergy between mitochondrial ND1 and ND4 mutations.
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Affiliation(s)
- Yanchun Ji
- Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Juanjuan Zhang
- Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.,Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Jialing Yu
- Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Ying Wang
- Department of Ophthalmology, Chinese Academy of Traditional Chinese Medicine, Beijing, China
| | - Yuanyuan Lu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.,Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Min Liang
- Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Qiang Li
- Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xiaofen Jin
- Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Yinsheng Wei
- Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Feilong Meng
- Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Yinglong Gao
- Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xiaohui Cang
- Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Yi Tong
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.,Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Xiaoling Liu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.,Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Minglian Zhang
- Department of Ophthalmology, Hebei Provincial Eye Hospital, Xingtai, Hebei, China
| | - Peifang Jiang
- Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Tao Zhu
- Department of Critical Care Medicine, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Jun Qin Mo
- Department of Pathology, Rady Children's Hospital, University of California School of Medicine, San Diego, California, USA
| | - Taosheng Huang
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Pingping Jiang
- Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Min-Xin Guan
- Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Key Lab of Reproductive Genetics, Ministry of Education of PRC, Zhejiang University, Hangzhou, China.,Joint Institute of Genetics and Genomic Medicine between Zhejiang University and University of Toronto, Hangzhou, Zhejiang, China
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39
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Pereira CV, Peralta S, Arguello T, Bacman SR, Diaz F, Moraes CT. Myopathy reversion in mice after restauration of mitochondrial complex I. EMBO Mol Med 2020; 12:e10674. [PMID: 31916679 PMCID: PMC7005622 DOI: 10.15252/emmm.201910674] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 12/04/2019] [Accepted: 12/06/2019] [Indexed: 01/03/2023] Open
Abstract
Myopathies are common manifestations of mitochondrial diseases. To investigate whether gene replacement can be used as an effective strategy to treat or cure mitochondrial myopathies, we have generated a complex I conditional knockout mouse model lacking NDUFS3 subunit in skeletal muscle. NDUFS3 protein levels were undetectable in muscle of 15‐day‐old smKO mice, and myopathy symptoms could be detected by 2 months of age, worsening over time. rAAV9‐Ndufs3 delivered systemically into 15‐ to 18‐day‐old mice effectively restored NDUFS3 levels in skeletal muscle, precluding the development of the myopathy. To test the ability of rAAV9‐mediated gene replacement to revert muscle function after disease onset, we also treated post‐symptomatic, 2‐month‐old mice. The injected mice showed a remarkable improvement of the mitochondrial myopathy and biochemical parameters, which remained for the duration of the study. Our results showed that muscle pathology could be reversed after restoring complex I, which was absent for more than 2 months. These findings have far‐reaching implications for the ability of muscle to tolerate a mitochondrial defect and for the treatment of mitochondrial myopathies.
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Affiliation(s)
- Claudia V Pereira
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Susana Peralta
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Tania Arguello
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Sandra R Bacman
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Francisca Diaz
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Carlos T Moraes
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA.,Department of Cell Biology, University of Miami Miller School of Medicine, Miami, FL, USA
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Abstract
PURPOSE OF REVIEW The diagnosis of visual loss from toxic-metabolic and hereditary optic neuropathies may be delayed in some cases because of a failure to elicit important information in the clinical history or to recognize typical examination findings. An understanding of the features specific to each type of toxic-metabolic and hereditary optic neuropathy, and of the underlying mechanism of insult to the optic nerve, could lead to earlier recognition, diagnosis, and treatment (when available). RECENT FINDINGS Understanding of the role of mitochondria in toxic-metabolic and hereditary optic neuropathies is growing, particularly regarding the mechanism of insult of certain agents (medications and toxins) and of vitamin B12 deficiency. New developments in the quest for treatment for hereditary optic neuropathy, specifically Leber hereditary optic neuropathy, are being seen. SUMMARY Toxic-metabolic and hereditary optic neuropathies present in a similar fashion, with painless, progressive, bilateral visual loss with dyschromatopsia and cecocentral visual field defects. The associated retinal ganglion cell and axonal loss is typically due to mitochondrial dysfunction caused by an exogenous agent (toxic), by insufficient or deficient substrate (metabolic or nutritional), or by abnormal proteins or mitochondrial structure determined by a genetic mutation (hereditary).
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Artika IM. Allotopic expression of mitochondrial genes: Basic strategy and progress. Genes Dis 2019; 7:578-584. [PMID: 33335957 PMCID: PMC7729113 DOI: 10.1016/j.gendis.2019.08.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 07/23/2019] [Accepted: 08/01/2019] [Indexed: 12/11/2022] Open
Abstract
Allotopic expression of mitochondrial genes is a deliberate functional relocation of mitochondrial genes into the nucleus followed by import of the gene-encoded polypeptide from the cytoplasm into the mitochondria. For successful allotopic expression of a mitochondrial gene, several key aspects must be considered. These include the different codon dictionary used by the mitochondrial and nuclear genomes, different codon preferences between mitochondrial and nuclear-cytosolic translation systems, and the provision of an import signal to ensure that the newly translated protein in the cytosol is successfully imported into mitochondria. The allotopic expression strategy was first developed in yeast, a useful model organism for studying human and other eukaryotic cells. Currently, a number of mitochondrial genes have been successfully recoded and nuclearly expressed in yeast and human cells. In addition to its use in evolutionary and molecular biology studies, the allotopic expression strategy has been developed as a potential approach to treat mitochondrial genetic disorders. Substantial progress has been recently achieved, and the development of this technique for therapy of the mitochondrial disease Leber's hereditary optic neuropathy (LHON) has entered phase III clinical trials. However, a number of challenges remain to be overcome to accelerate the successful application of this technique. These include improvement of nuclear gene expression, import into mitochondria, processing, and functional integration of the allotopically expressed polypeptides into mitochondrial protein complexes. This review discusses the current basic strategy, progress, challenges, and prospects of the allotopic expression strategy for mitochondrial genes.
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Affiliation(s)
- I. Made Artika
- Department of Biochemistry, Faculty of Mathematics and Natural Sciences, Bogor Agricultural University, Darmaga Campus, Bogor 16680, Indonesia
- Eijkman Institute for Molecular Biology, Jalan Diponegoro 69, Jakarta, 10430, Indonesia
- Department of Biochemistry, Faculty of Mathematics and Natural Sciences, Bogor Agricultural University, Darmaga Campus, Bogor 16680, Indonesia
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Gospe SM, Travis AM, Kolesnikov AV, Klingeborn M, Wang L, Kefalov VJ, Arshavsky VY. Photoreceptors in a mouse model of Leigh syndrome are capable of normal light-evoked signaling. J Biol Chem 2019; 294:12432-12443. [PMID: 31248988 DOI: 10.1074/jbc.ra119.007945] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 06/12/2019] [Indexed: 11/06/2022] Open
Abstract
Mitochondrial dysfunction is an important cause of heritable vision loss. Mutations affecting mitochondrial bioenergetics may lead to isolated vision loss or life-threatening systemic disease, depending on a mutation's severity. Primary optic nerve atrophy resulting from death of retinal ganglion cells is the most prominent ocular manifestation of mitochondrial disease. However, dysfunction of other retinal cell types has also been described, sometimes leading to a loss of photoreceptors and retinal pigment epithelium that manifests clinically as pigmentary retinopathy. A popular mouse model of mitochondrial disease that lacks NADH:ubiquinone oxidoreductase subunit S4 (NDUFS4), a subunit of mitochondrial complex I, phenocopies many traits of the human disease Leigh syndrome, including the development of optic atrophy. It has also been reported that ndufs4 -/- mice display diminished light responses at the level of photoreceptors or bipolar cells. By conducting electroretinography (ERG) recordings in live ndufs4 -/- mice, we now demonstrate that this defect occurs at the level of retinal photoreceptors. We found that this deficit does not arise from retinal developmental anomalies, photoreceptor degeneration, or impaired regeneration of visual pigment. Strikingly, the impairment of ndufs4 -/- photoreceptor function was not observed in ex vivo ERG recordings from isolated retinas, indicating that photoreceptors with complex I deficiency are intrinsically capable of normal signaling. The difference in electrophysiological phenotypes in vivo and ex vivo suggests that the energy deprivation associated with severe mitochondrial impairment in the outer retina renders ndufs4 -/- photoreceptors unable to maintain the homeostatic conditions required to operate at their normal capacity.
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Affiliation(s)
- Sidney M Gospe
- Department of Ophthalmology, Duke University, Durham, North Carolina 27710.
| | - Amanda M Travis
- Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina 27710
| | - Alexander V Kolesnikov
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Saint Louis, Missouri 63110
| | - Mikael Klingeborn
- Department of Ophthalmology, Duke University, Durham, North Carolina 27710
| | - Luyu Wang
- Department of Ophthalmology, Duke University, Durham, North Carolina 27710
| | - Vladimir J Kefalov
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Saint Louis, Missouri 63110
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University, Durham, North Carolina 27710; Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina 27710
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Yang YP, Nguyen PNN, Lin TC, Yarmishyn AA, Chen WS, Hwang DK, Chiou GY, Lin TW, Chien CS, Tsai CY, Chiou SH, Chen SJ, Peng CH, Hsu CC. Glutamate Stimulation Dysregulates AMPA Receptors-Induced Signal Transduction Pathway in Leber's Inherited Optic Neuropathy Patient-Specific hiPSC-Derived Retinal Ganglion Cells. Cells 2019; 8:cells8060625. [PMID: 31234430 PMCID: PMC6627514 DOI: 10.3390/cells8060625] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 06/14/2019] [Accepted: 06/19/2019] [Indexed: 11/16/2022] Open
Abstract
The mitochondrial genetic disorder, Leber’s hereditary optic neuropathy (LHON), is caused by a mutation in MT-ND4 gene, encoding NADH dehydrogenase subunit 4. It leads to the progressive death of retinal ganglion cells (RGCs) and causes visual impairment or even blindness. However, the precise mechanisms of LHON disease penetrance and progression are not completely elucidated. Human-induced pluripotent stem cells (hiPSCs) offer unique opportunities to investigate disease-relevant phenotypes and regulatory mechanisms underlying LHON pathogenesis at the cellular level. In this study, we successfully generated RGCs by differentiation of LHON patient-specific hiPSCs. We modified the protocol of differentiation to obtain a more enriched population of single-cell RGCs for LHON study. Based on assessing morphology, expression of specific markers and electrophysiological activity, we found that LHON-specific hiPSC-derived were more defective in comparison with normal wild-type RGCs. Based on our previous study, whereby by using microarray analysis we identified that the components of glutamatergic synapse signaling pathway were significantly downregulated in LHON-specific RGCs, we focused our study on glutamate-associated α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors. We found that the protein expression levels of the subunits of the AMPA receptor, GluR1 and GluR2, and their associated scaffold proteins were decreased in LHON-RGCs. By performing the co-immunoprecipitation assay, we found several differences in the efficiencies of interaction between AMPA subunits and scaffold proteins between normal and LHON-specific RGCs.
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Affiliation(s)
- Yi-Ping Yang
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 112, Taiwan.
- School of Medicine, National Yang-Ming University, Taipei 112, Taiwan.
- School of Pharmaceutical Sciences, National Yang-Ming University, Taipei 112, Taiwan.
| | - Phan Nguyen Nhi Nguyen
- Cancer Center, Taipei Veterans General Hospital, Taipei 112, Taiwan.
- Department of Neurological Surgery, Tri-Service General Hospital and National Defense Medical Center, Taipei 114, Taiwan.
| | - Tai-Chi Lin
- School of Medicine, National Yang-Ming University, Taipei 112, Taiwan.
- Institute of Clinical Medicine, School of Medicine, National Yang-Ming University, Taipei 112, Taiwan.
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 112, Taiwan.
| | - Aliaksandr A Yarmishyn
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 112, Taiwan.
- Institute of Pharmacology, National Yang-Ming University, Taipei 112, Taiwan.
| | - Wun-Syuan Chen
- Institute of Pharmacology, National Yang-Ming University, Taipei 112, Taiwan.
| | - De-Kuang Hwang
- School of Medicine, National Yang-Ming University, Taipei 112, Taiwan.
- Institute of Clinical Medicine, School of Medicine, National Yang-Ming University, Taipei 112, Taiwan.
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 112, Taiwan.
| | - Guang-Yuh Chiou
- Department of Biological Science and Technology, College of Biological Science and Technology, National Chiao Tung University, Hsinchu 300, Taiwan.
| | - Tzu-Wei Lin
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 112, Taiwan.
| | - Chian-Shiu Chien
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 112, Taiwan.
- Institute of Pharmacology, National Yang-Ming University, Taipei 112, Taiwan.
| | - Ching-Yao Tsai
- School of Medicine, National Yang-Ming University, Taipei 112, Taiwan.
- Department of Ophthalmology, Taipei City Hospital, Taipei 103, Taiwan.
| | - Shih-Hwa Chiou
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 112, Taiwan.
- Institute of Pharmacology, National Yang-Ming University, Taipei 112, Taiwan.
- Genomic Research Center, Academia Sinica, Taipei 115, Taiwan.
| | - Shih-Jen Chen
- School of Medicine, National Yang-Ming University, Taipei 112, Taiwan.
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 112, Taiwan.
| | - Chi-Hsien Peng
- Department of Ophthalmology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei 111, Taiwan.
- Department of Ophthalmology, Fu-Jen Catholic University, Taipei 242, Taiwan.
| | - Chih-Chien Hsu
- Institute of Clinical Medicine, School of Medicine, National Yang-Ming University, Taipei 112, Taiwan.
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 112, Taiwan.
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Chen Z, Zhang F, Xu H. Human mitochondrial DNA diseases and Drosophila models. J Genet Genomics 2019; 46:201-212. [DOI: 10.1016/j.jgg.2019.03.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 03/05/2019] [Accepted: 03/25/2019] [Indexed: 01/06/2023]
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45
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Zhang J, Ji Y, Lu Y, Fu R, Xu M, Liu X, Guan MX. Leber's hereditary optic neuropathy (LHON)-associated ND5 12338T > C mutation altered the assembly and function of complex I, apoptosis and mitophagy. Hum Mol Genet 2019; 27:1999-2011. [PMID: 29579248 DOI: 10.1093/hmg/ddy107] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 03/19/2018] [Indexed: 02/04/2023] Open
Abstract
Mutations in mitochondrial DNA (mtDNA) have been associated with Leber's hereditary optic neuropathy (LHON) and their pathophysiology remains poorly understood. In this study, we demonstrated that a missense mutation (m.12338T>C, p.1M>T) in the ND5 gene contributed to the pathogenesis of LHON. The m.12338T>C mutation affected the first methionine (Met1) with a threonine and shortened two amino acids of ND5. We therefore hypothesized that the mutated ND5 perturbed the structure and function of complex I. Using the cybrid cell models, generated by fusing mtDNA-less (ρ°) cells with enucleated cells from LHON patients carrying the m.12338T>C mutation and a control subject belonging to the same mtDNA haplogroup, we demonstrated that the m.12338T>C mutation caused the reduction of ND5 polypeptide, perturbed assemble and activity of complex I. Furthermore, the m.12338T>C mutation caused respiratory deficiency, diminished mitochondrial adenosine triphosphate levels and membrane potential and increased the production of reactive oxygen species. The m.12338T>C mutation promoted apoptosis, evidenced by elevated release of cytochrome c into cytosol and increased levels of apoptosis-activated proteins: caspases 9, 3, 7 and Poly ADP ribose polymerase in the cybrids carrying the m.12338T>C mutation, as compared with control cybrids. Moreover, we also document the involvement of m.12338T>C mutation in decreased mitophagy, as showed by reduced levels of autophagy protein light chain 3 and accumulation of autophagic substrate p62 in the in mutant cybrids as compared with control cybrids. These data demonstrated the direct link between mitochondrial dysfunction caused by complex I mutation and apoptosis or mitophagy. Our findings may provide new insights into the pathophysiology of LHON.
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Affiliation(s)
- Juanjuan Zhang
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310052, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang 325600, China.,Attardi Institute of Mitochondrial Biomedicine, School of Life Sciences, Wenzhou Medical College, Wenzhou, Zhejiang 325035, China
| | - Yanchun Ji
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310052, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Yuanyuan Lu
- Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang 325600, China.,Attardi Institute of Mitochondrial Biomedicine, School of Life Sciences, Wenzhou Medical College, Wenzhou, Zhejiang 325035, China
| | - Runing Fu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang 325600, China.,Attardi Institute of Mitochondrial Biomedicine, School of Life Sciences, Wenzhou Medical College, Wenzhou, Zhejiang 325035, China
| | - Man Xu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang 325600, China.,Attardi Institute of Mitochondrial Biomedicine, School of Life Sciences, Wenzhou Medical College, Wenzhou, Zhejiang 325035, China
| | - Xiaoling Liu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang 325600, China.,Attardi Institute of Mitochondrial Biomedicine, School of Life Sciences, Wenzhou Medical College, Wenzhou, Zhejiang 325035, China
| | - Min-Xin Guan
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310052, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang 325600, China.,Attardi Institute of Mitochondrial Biomedicine, School of Life Sciences, Wenzhou Medical College, Wenzhou, Zhejiang 325035, China.,Joint Institute of Genetics and Genome Medicine between Zhejiang University and University of Toronto, Hangzhou, Zhejiang, China
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Sharma LK, Tiwari M, Rai NK, Bai Y. Mitophagy activation repairs Leber's hereditary optic neuropathy-associated mitochondrial dysfunction and improves cell survival. Hum Mol Genet 2019; 28:422-433. [PMID: 30304398 PMCID: PMC6489411 DOI: 10.1093/hmg/ddy354] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 08/31/2018] [Accepted: 09/26/2018] [Indexed: 12/24/2022] Open
Abstract
Leber's hereditary optic neuropathy (LHON) is a classical mitochondrial disease caused by mutations in the mitochondrial DNA encoding complex I subunits. Oxidative stress associated with complex I defect has been implicated in developing LHON phenotype such as retinal ganglion cell (RGC) death and loss of vision. However, the mechanism of LHON pathogenesis is still not very clear and thus no effective therapies are available to date. Using cybrid models for LHON, we show that autophagy is significantly compromised in cells carrying LHON-specific mtDNA mutations, which results in reduced clearance of dysfunctional mitochondria contributing to cell death. We further show that pharmacological activation of autophagy selectively clears the damaged mitochondria and thus repairs mitochondrial defects and improves overall cell survival in LHON cell models. Our results suggest that compromised autophagy is the missing link from oxidative stress to LHON pathogenesis. Activation of mitophagy ameliorates mitochondrial defects and exerts a protective role by improving cell survival in cells carrying LHON mutations that could be utilized as a potential therapeutic target for LHON treatment.
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Affiliation(s)
- Lokendra Kumar Sharma
- Department of Cell Systems and Anatomy, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
- Department of Biotechnology, Centre for Biological Sciences, Central University of South Bihar, Gaya, Bihar, India
| | - Meenakshi Tiwari
- Department of Cell Systems and Anatomy, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
- Department of Pathology / Lab Medicine, All India Institute of Medical Sciences-Patna, Phulwarisharif, Patna, Bihar, India
| | - Neeraj Kumar Rai
- Department of Biotechnology, Centre for Biological Sciences, Central University of South Bihar, Gaya, Bihar, India
| | - Yidong Bai
- Department of Cell Systems and Anatomy, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
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Bioactivity and gene expression profiles of hiPSC-generated retinal ganglion cells in MT-ND4 mutated Leber's hereditary optic neuropathy. Exp Cell Res 2018; 363:299-309. [PMID: 29366807 DOI: 10.1016/j.yexcr.2018.01.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 01/09/2018] [Accepted: 01/15/2018] [Indexed: 01/01/2023]
Abstract
Leber's hereditary optic neuropathy (LHON) is the maternally inherited mitochondrial disease caused by homoplasmic mutations in mitochondrial electron transport chain Complex I subunit genes. The mechanism of its incomplete penetrance is still largely unclear. In this study, we created the patient-specific human induced pluripotent stem cells (hiPSCs) from MT-ND4 mutated LHON-affected patient, asymptomatic mutation carrier and healthy control, and differentiated them into retinal ganglion cells (RGCs). We found the defective neurite outgrowth in affected RGCs, but not in the carrier RGCs which had significant expression of SNCG gene. We observed enhanced mitochondrial biogenesis in affected and carrier derived RGCs. Surprisingly, we observed increased NADH dehydrogenase enzymatic activity of Complex I in hiPSC-derived RGCs of asymptomatic carrier, but not of the affected patient. LHON mutation substantially decreased basal respiration in both affected and unaffected carrier hiPSCs, and had the same effect on spare respiratory capacity, which ensures normal function of mitochondria in conditions of increased energy demand or environmental stress. The expression of antioxidant enzyme catalase was decreased in affected and carrier patient hiPSC-derived RGCs as compared to the healthy control, which might indicate to higher oxidative stress-enriched environment in the LHON-specific RGCs. Microarray profiling demonstrated enhanced expression of cell cycle machinery and downregulation of neuronal specific genes.
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Ueki Y, Shchepetkina V, Lefcort F. Retina-specific loss of Ikbkap/Elp1 causes mitochondrial dysfunction that leads to selective retinal ganglion cell degeneration in a mouse model of familial dysautonomia. Dis Model Mech 2018; 11:dmm.033746. [PMID: 29929962 PMCID: PMC6078410 DOI: 10.1242/dmm.033746] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 06/12/2018] [Indexed: 12/26/2022] Open
Abstract
Familial dysautonomia (FD) is an autosomal recessive disorder marked by developmental and progressive neuropathies. It is caused by an intronic point-mutation in the IKBKAP/ELP1 gene, which encodes the inhibitor of κB kinase complex-associated protein (IKAP, also called ELP1), a component of the elongator complex. Owing to variation in tissue-specific splicing, the mutation primarily affects the nervous system. One of the most debilitating hallmarks of FD that affects patients' quality of life is progressive blindness. To determine the pathophysiological mechanisms that are triggered by the absence of IKAP in the retina, we generated retina-specific Ikbkap conditional knockout (CKO) mice using Pax6-Cre, which abolished Ikbkap expression in all cell types of the retina. Although sensory and autonomic neuropathies in FD are known to be developmental in origin, the loss of IKAP in the retina did not affect its development, demonstrating that IKAP is not required for retinal development. The loss of IKAP caused progressive degeneration of retinal ganglion cells (RGCs) by 1 month of age. Mitochondrial membrane integrity was breached in RGCs, and later in other retinal neurons. In Ikbkap CKO retinas, mitochondria were depolarized, and complex I function and ATP were significantly reduced. Although mitochondrial impairment was detected in all Ikbkap-deficient retinal neurons, RGCs were the only cell type to degenerate; the survival of other retinal neurons was unaffected. This retina-specific FD model is a useful in vivo model for testing potential therapeutics for mitigating blindness in FD. Moreover, our data indicate that RGCs and mitochondria are promising targets. Summary: The elongator subunit IKBKAP/ELP1 is not required for development, but is essential for maintaining mitochondrial function and retina morphology. Loss of this subunit causes progressive, selective degeneration of retinal ganglion cells.
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Affiliation(s)
- Yumi Ueki
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA
| | - Veronika Shchepetkina
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA
| | - Frances Lefcort
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA
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Cybrid Models of Pathological Cell Processes in Different Diseases. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:4647214. [PMID: 29983856 PMCID: PMC6015674 DOI: 10.1155/2018/4647214] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 07/26/2017] [Accepted: 05/02/2018] [Indexed: 11/22/2022]
Abstract
Modelling of pathological processes in cells is one of the most sought-after technologies of the 21st century. Using models of such processes may help to study the pathogenetic mechanisms of various diseases. The aim of the present study was to analyse the literature, dedicated to obtaining and investigating cybrid models. Besides, the possibility of modeling pathological processes in cells and treatment of different diseases using the models was evaluated. Methods of obtaining Rho0 cell cultures showed that, during their creation, mainly a standard technique, based on the use of mtDNA replication inhibitors (ethidium bromide), was applied. Cybrid lines were usually obtained by PEG fusion. Most frequently, platelets acted as donors of mitochondria. According to the analysis of the literature data, cybrid cell cultures can be modeled to study the dysfunction of the mitochondrial genome and molecular cellular pathological processes. Such models can be very promising for the development of therapeutic approaches to the treatment of various human diseases.
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Chin RM, Panavas T, Brown JM, Johnson KK. Patient-derived lymphoblastoid cell lines harboring mitochondrial DNA mutations as tool for small molecule drug discovery. BMC Res Notes 2018; 11:205. [PMID: 29587845 PMCID: PMC5870301 DOI: 10.1186/s13104-018-3297-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Accepted: 03/20/2018] [Indexed: 11/10/2022] Open
Abstract
Objective Mitochondrial diseases are a group of devastating disorders for which there is no transformative cure. The majority of therapies for mitochondrial disease—approved, previously tested, or currently in development—are small molecules. The implementation of better cell-based models of mitochondrial disease can accelerate and improve the accuracy of small molecule drug discovery. The objective of this study is to evaluate the use of patient-derived lymphoblastoid cell lines for small molecule research in mitochondrial disease. Results Five lymphoblastoid cell lines derived from mitochondrial disease patients harboring point mutations in mtND1, mtND4, or mtATP6 were characterized in two high throughput assays assessing mitochondrial function. In a pilot “clinical trial in a dish” experiment, the efficacy of idebenone—an approved therapy for mitochondrial disease—on the lymphoblastoid cell lines was tested. Idebenone increased the basal respiration of all lymphoblastoid cell lines except those harboring the 8993T>G point mutation in mtATP6. Our results posit lymphoblastoid cell lines as a strong model for mitochondrial disease research with small molecules and have implications for the clinical efficacy of idebenone.
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Affiliation(s)
| | - Tadas Panavas
- Biotherapeutic Molecule Discovery, Boehringer Ingelheim Pharmaceuticals, 900 Ridgebury Road, Ridgefield, CT, 06877, USA
| | - Jeffrey M Brown
- Wave Life Sciences, 733 Concord Ave., Cambridge, MA, 02138, USA
| | - Krista K Johnson
- Alexion Pharmaceuticals, Inc., 100 College Street, New Haven, CT, 06510, USA
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