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Zhang Y, Sun X, Tian G, Chen Y. Comparison of the clinical and genetic features of autosomal dominant optic atrophy and normal tension glaucoma in young Chinese adults. Eye (Lond) 2023; 37:624-630. [PMID: 35273349 PMCID: PMC9998393 DOI: 10.1038/s41433-022-01990-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 01/30/2022] [Accepted: 02/15/2022] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND/OBJECTIVES To compare the clinical and optical coherence tomography (OCT) characteristics of autosomal dominant optic atrophy (ADOA) and normal tension glaucoma (NTG) in Chinese patients. SUBJECTS/METHODS Twenty-four unrelated patients with ADOA and 21 unrelated patients with NTG, younger than 30 years, were enrolled in this study. Data regarding the demographic and clinical characteristics of the patients were collected, and their peripapillary retinal nerve fibre layer (RNFL) and macular ganglion cell complex (GCC) thicknesses were evaluated using OCT. Sequencing of genes associated with neuro-ophthalmic disorders was performed for all patients. RESULTS The average age at onset of the ADOA group (13.92 ± 10.73 years) was significantly younger than that of the NTG group (23.67 ± 4.98 years, P = 0.002). Best-corrected visual acuity was significantly poorer in the ADOA group (0.75 ± 0.32) than in the NTG group (0.16 ± 0.19, P < 0.001). The average peripapillary RNFL thickness and the RNFL thicknesses in the temporal upper, temporal lower, and nasal lower sectors were significantly thinner in the ADOA group than in the NTG group (all P < 0.05). Moreover, the macular GCC thickness of the ADOA group was significantly thinner than that of the NTG group (P < 0.001). Twenty-three OPA1 variants (11 novel OPA1 variants) and one OPA3 variant were detected in 24 patients with ADOA. CONCLUSIONS Our study revealed a distinct difference between the patterns of RNFL and GCC loss in ADOA and NTG, which will help to differentiate ADOA from NTG in young patients. Additionally, this study expanded the genetic spectrum of ADOA.
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Affiliation(s)
- Youjia Zhang
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Xinghuai Sun
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China
| | - Guohong Tian
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
| | - Yuhong Chen
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
- NHC Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China.
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Huang ZN, Chung HM, Fang SC, Her LS. Adhesion Regulating Molecule 1 Mediates HAP40 Overexpression-Induced Mitochondrial Defects. Int J Biol Sci 2017; 13:1420-1437. [PMID: 29209146 PMCID: PMC5715525 DOI: 10.7150/ijbs.20742] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 09/10/2017] [Indexed: 12/29/2022] Open
Abstract
Striatal neuron death in Huntington's disease is associated with abnormal mitochondrial dynamics and functions. However, the mechanisms for this mitochondrial dysregulation remain elusive. Increased accumulation of Huntingtin-associated protein 40 (HAP40) has been shown to be associated with Huntington's disease. However, the link between increased HAP40 and Huntington's disease remains largely unknown. Here we show that HAP40 overexpression causes mitochondrial dysfunction and reduces cell viability in the immortalized mouse striatal neurons. HAP40-associated mitochondrial dysfunction is associated with reduction of adhesion regulating molecule 1 (ADRM1) protein. Consistently, depletion of ADRM1 by shRNAs impaired mitochondrial functions and increased mitochondrial fragmentation in mouse striatal cells. Moreover, reducing ADRM1 levels enhanced activity of fission factor dynamin-related GTPase protein 1 (Drp1) via increased phosphorylation at serine 616 of Drp1 (Drp1Ser616). Restoring ADRM1 protein levels was able to reduce HAP40-induced ROS levels and mitochondrial fragmentation and improved mitochondrial functions and cell viability. Moreover, reducing Drp1 activity by Drp1 inhibitor, Mdivi-1, ameliorates both HAP40 overexpression- and ADRM1 depletion-induced mitochondrial dysfunction. Taken together, our studies suggest that HAP40-mediated reduction of ADRM1 alters the mitochondrial fission activity and results in mitochondrial fragmentation and mitochondrial dysfunction.
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Affiliation(s)
- Zih-Ning Huang
- Department of Life Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan 70101, Taiwan
| | - Her Min Chung
- Department of Life Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan 70101, Taiwan
| | - Su-Chiung Fang
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan 741, Taiwan.,Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Lu-Shiun Her
- Department of Life Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan 70101, Taiwan
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Finsterer J, Mancuso M, Pareyson D, Burgunder JM, Klopstock T. Mitochondrial disorders of the retinal ganglion cells and the optic nerve. Mitochondrion 2017; 42:1-10. [PMID: 29054473 DOI: 10.1016/j.mito.2017.10.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 10/02/2017] [Accepted: 10/06/2017] [Indexed: 12/13/2022]
Abstract
OBJECTIVES To summarise and discuss recent findings and future perspectives concerning mitochondrial disorders (MIDs) affecting the retinal ganglion cells and the optic nerve (mitochondrial optic neuropathy. MON). METHOD Literature review. RESULTS MON in MIDs is more frequent than usually anticipated. MON may occur in specific as well as non-specific MIDs. In specific and non-specific MIDs, MON may be a prominent or non-prominent phenotypic feature and due to mutations in genes located either in the mitochondrial DNA (mtDNA) or the nuclear DNA (nDNA). Clinically, MON manifests with painless, bilateral or unilateral, slowly or rapidly progressive visual impairment and visual field defects. In some cases, visual impairment may spontaneously recover. The most frequent MIDs with MON include LHON due to mutations in mtDNA-located genes and autosomal dominant optic atrophy (ADOA) or autosomal recessive optic atrophy (AROA) due to mutations in nuclear genes. Instrumental investigations for diagnosing MON include fundoscopy, measurement of visual acuity, visual fields, and color vision, visually-evoked potentials, optical coherence tomography, fluorescein angiography, electroretinography, and MRI of the orbita and cerebrum. In non-prominent MON, work-up of the muscle biopsy with transmission electron microscopy may indicate mitochondrial destruction. Treatment is mostly supportive but idebenone has been approved for LHON and experimental approaches are promising. CONCLUSIONS MON needs to be appreciated, requires extensive diagnostic work-up, and supportive treatment should be applied although loss of vision, as the most severe outcome, can often not be prevented.
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Affiliation(s)
| | - Michelangelo Mancuso
- Department of Clinical and Experimental Medicine, Neurological Clinic, University of Pisa, Italy
| | - Davide Pareyson
- Department of Clinical Neurosciences, C. Besta Neurological Institute, IRCCS Foundation, Milan, Italy.
| | - Jean-Marc Burgunder
- Department of Neurology, University of Bern, Switzerland; Department of Neurology, Sun Yat Sen University, Guangzhou, China; Department of Neurology, Sichuan University, Chendgu, China.
| | - Thomas Klopstock
- Department of Neurology, Friedrich-Baur Institute, Ludwig-Maximilians-Universität München, Munich, Germany; German Center for Neurodegenerative Diseases (DZNE), Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.
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Zhang J, Liu X, Liang X, Lu Y, Zhu L, Fu R, Ji Y, Fan W, Chen J, Lin B, Yuan Y, Jiang P, Zhou X, Guan MX. A novel ADOA-associated OPA1 mutation alters the mitochondrial function, membrane potential, ROS production and apoptosis. Sci Rep 2017; 7:5704. [PMID: 28720802 PMCID: PMC5515948 DOI: 10.1038/s41598-017-05571-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 05/31/2017] [Indexed: 12/18/2022] Open
Abstract
Autosomal dominant optic atrophy (ADOA) is a dominantly inherited optic neuropathy, affecting the specific loss of retinal ganglion cells (RGCs). The majority of affected cases of ADOA are associated with mutations in OPA1 gene. Our previous investigation identified the c.1198C > G (p.P400A) mutation in the OPA1 in a large Han Chinese family with ADOA. In this report, we performed a functional characterization using lymphoblostoid cell lines derived from affected members of this family and control subjects. Mutant cell lines exhibited the aberrant mitochondrial morphology. A ~24.6% decrease in the mitochondrial DNA (mtDNA) copy number was observed in mutant cell lines, as compared with controls. Western blotting analysis revealed the variable reductions (~45.7%) in four mtDNA-encoded polypeptides in mutant cell lines. The impaired mitochondrial translation caused defects in respiratory capacity. Furthermore, defects in mitochondrial ATP synthesis and mitochondrial membrane potential (ΔΨm) were observed in mutant cell lines. These abnormalities resulted in the accumulation of oxidative damage and increasing of apoptosis in the mutant cell lines, as compared with controls. All those alterations may cause the primary degeneration of RGCs and subsequent visual loss. These data provided the direct evidence for c.1198C > G mutation leading to ADOA. Our findings may provide new insights into the understanding of pathophysiology of ADOA.
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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, 310058, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China.,School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, 325027, China
| | - Xiaoling Liu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, 325027, China
| | - Xiaoyang Liang
- Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China
| | - Yuanyuan Lu
- Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, China
| | - Ling Zhu
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China
| | - Runing Fu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, 325027, China.,Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, China
| | - Yanchun Ji
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China
| | - Wenlu Fan
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, 325027, China
| | - Jie Chen
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, 325027, China
| | - Bing Lin
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, 325027, China
| | - Yimin Yuan
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, 325027, China.,Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, China
| | - Pingping Jiang
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China
| | - Xiangtian Zhou
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, 325027, China.
| | - Min-Xin Guan
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China. .,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China. .,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou, Zhejiang, 310058, China.
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Molecular Impairment Mechanisms of Novel OPA1 Mutations Predicted by Molecular Modeling in Patients With Autosomal Dominant Optic Atrophy and Auditory Neuropathy Spectrum Disorder. Otol Neurotol 2016; 37:394-402. [PMID: 26905822 DOI: 10.1097/mao.0000000000000978] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
HYPOTHESIS Different missense mutations of the optic atrophy 1 gene (OPA1) identified in optic atrophy patients with auditory neuropathy spectrum disorder (ANSD) induce functional impairment through different molecular mechanisms. BACKGROUND OPA1 is the gene responsible for autosomal dominant optic atrophy (ADOA), but some of its mutations are also associated with ANSD. OPA1 is a member of the GTPase family of proteins and plays a key role in the maintenance of mitochondrial activities that are dependent on dimer formation of the protein. There are many reports of OPA1 mutations, but the molecular mechanisms of their functional impairments are unclear. METHODS The sequences of coding regions in OPA1 were analyzed from blood samples of ADOA patients with ANSD. Molecular modeling of the protein's ability to form dimers and its GTP-binding ability were conducted to study the effects of structural changes in OPA1 caused by two identified mutations and their resultant effects on protein function. RESULTS Two heterozygous mutations, p.T414P (c.1240A>C) and p.T540P (c.1618A>C), located in the GTPase and middle domains of OPA1, respectively, were identified in two patients. Molecular modeling indicated decreased dimer formation caused by destabilization of the association structure of the p.T414P mutant, and decreased GTP-binding caused by destabilization of the binding site structure in the p.T540P mutant. CONCLUSION These two different conformational changes might result in decreased GTPase activities that trigger ADOA associated with ANSD, and are likely to be associated with mild clinical features. Molecular modeling would provide useful information in clinical practice.
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