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Taub DG, Woolf CJ. Age-dependent small fiber neuropathy: Mechanistic insights from animal models. Exp Neurol 2024; 377:114811. [PMID: 38723859 PMCID: PMC11131160 DOI: 10.1016/j.expneurol.2024.114811] [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: 01/26/2024] [Revised: 04/07/2024] [Accepted: 05/05/2024] [Indexed: 05/28/2024]
Abstract
Small fiber neuropathy (SFN) is a common and debilitating disease in which the terminals of small diameter sensory axons degenerate, producing sensory loss, and in many patients neuropathic pain. While a substantial number of cases are attributable to diabetes, almost 50% are idiopathic. An underappreciated aspect of the disease is its late onset in most patients. Animal models of human genetic mutations that produce SFN also display age-dependent phenotypes suggesting that aging is an important contributor to the risk of development of the disease. In this review we define how particular sensory neurons are affected in SFN and discuss how aging may drive the disease. We also evaluate how animal models of SFN can define disease mechanisms that will provide insight into early risk detection and suggest novel therapeutic interventions.
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Affiliation(s)
- Daniel G Taub
- F. M. Kirby Neurobiology Center and Department of Neurology, Boston Children's Hospital, Boston, MA, USA; Department of Neurobiology, Harvard Medical School, Boston, MA, USA.
| | - Clifford J Woolf
- F. M. Kirby Neurobiology Center and Department of Neurology, Boston Children's Hospital, Boston, MA, USA; Department of Neurobiology, Harvard Medical School, Boston, MA, USA
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2
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Ouyang KW, Wang TT, Wang H, Luo YX, Hu YF, Zheng XM, Ling Q, Wang KW, Xiong YW, Zhang J, Chang W, Zhang YF, Yuan Z, Li H, Gao L, Xu DX, Zhu HL, Yang L, Wang H. m6A-methylated Lonp1 drives mitochondrial proteostasis stress to induce testicular pyroptosis upon environmental cadmium exposure. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 931:172938. [PMID: 38703850 DOI: 10.1016/j.scitotenv.2024.172938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2024] [Revised: 04/15/2024] [Accepted: 04/30/2024] [Indexed: 05/06/2024]
Abstract
Cadmium (Cd) is a widely distributed typical environmental pollutant and one of the most toxic heavy metals. It is well-known that environmental Cd causes testicular damage by inducing classic types of cell death such as cell apoptosis and necrosis. However, as a new type of cell death, the role and mechanism of pyroptosis in Cd-induced testicular injury remain unclear. In the current study, we used environmental Cd to generate a murine model with testicular injury and AIM2-dependent pyroptosis. Based on the model, we found that increased cytoplasmic mitochondrial DNA (mtDNA), activated mitochondrial proteostasis stress occurred in Cd-exposed testes. We used ethidium bromide to generate mtDNA-deficient testicular germ cells and further confirmed that increased cytoplasmic mtDNA promoted AIM2-dependent pyroptosis in Cd-exposed cells. Uracil-DNA glycosylase UNG1 overexpression indicated that environmental Cd blocked UNG-dependent repairment of damaged mtDNA to drive the process in which mtDNA releases to cytoplasm in the cells. Interestingly, we found that environmental Cd activated mitochondrial proteostasis stress by up-regulating protein expression of LONP1 in testes. Testicular specific LONP1-knockdown significantly reversed Cd-induced UNG1 protein degradation and AIM2-dependent pyroptosis in mouse testes. In addition, environmental Cd significantly enhanced the m6A modification of Lonp1 mRNA and its stability in testicular germ cells. Knockdown of IGF2BP1, a reader of m6A modification, reversed Cd-induced upregulation of LONP1 protein expression and pyroptosis activation in testicular germ cells. Collectively, environmental Cd induces m6A modification of Lonp1 mRNA to activate mitochondrial proteostasis stress, increase cytoplasmic mtDNA content, and trigger AIM2-dependent pyroptosis in mouse testes. These findings suggest that mitochondrial proteostasis stress is a potential target for the prevention of testicular injury.
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Affiliation(s)
- Kong-Wen Ouyang
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China; Center of Prenatal Diagnosis, Wuxi Maternity and Child Health Care Hospital, Affiliated Women's Hospital of Jiangnan University, Wuxi 214000, China
| | - Tian-Tian Wang
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Hua Wang
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China; Department of Respiratory Medicine, Anhui Provincial Children's Hospital, Hefei, Anhui 230000, China
| | - Ye-Xin Luo
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Yi-Fan Hu
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Xin-Mei Zheng
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Qing Ling
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Kai-Wen Wang
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Yong-Wei Xiong
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China; Key Laboratory of Population Health Across Life Cycle (Anhui Medical University), Ministry of Education of The People's Republic of China, No 81 Meishan Road, Hefei 230032, Anhui, China
| | - Jin Zhang
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Wei Chang
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Yu-Feng Zhang
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Zhi Yuan
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Hao Li
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Lan Gao
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China; Key Laboratory of Population Health Across Life Cycle (Anhui Medical University), Ministry of Education of The People's Republic of China, No 81 Meishan Road, Hefei 230032, Anhui, China
| | - De-Xiang Xu
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China; Key Laboratory of Population Health Across Life Cycle (Anhui Medical University), Ministry of Education of The People's Republic of China, No 81 Meishan Road, Hefei 230032, Anhui, China
| | - Hua-Long Zhu
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China; Key Laboratory of Population Health Across Life Cycle (Anhui Medical University), Ministry of Education of The People's Republic of China, No 81 Meishan Road, Hefei 230032, Anhui, China.
| | - Lan Yang
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Center of Prenatal Diagnosis, Wuxi Maternity and Child Health Care Hospital, Affiliated Women's Hospital of Jiangnan University, Wuxi 214000, China.
| | - Hua Wang
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China; Key Laboratory of Population Health Across Life Cycle (Anhui Medical University), Ministry of Education of The People's Republic of China, No 81 Meishan Road, Hefei 230032, Anhui, China.
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3
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Bernardino Gomes TM, Vincent AE, Menger KE, Stewart JB, Nicholls TJ. Mechanisms and pathologies of human mitochondrial DNA replication and deletion formation. Biochem J 2024; 481:683-715. [PMID: 38804971 DOI: 10.1042/bcj20230262] [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: 03/22/2024] [Revised: 05/13/2024] [Accepted: 05/14/2024] [Indexed: 05/29/2024]
Abstract
Human mitochondria possess a multi-copy circular genome, mitochondrial DNA (mtDNA), that is essential for cellular energy metabolism. The number of copies of mtDNA per cell, and their integrity, are maintained by nuclear-encoded mtDNA replication and repair machineries. Aberrant mtDNA replication and mtDNA breakage are believed to cause deletions within mtDNA. The genomic location and breakpoint sequences of these deletions show similar patterns across various inherited and acquired diseases, and are also observed during normal ageing, suggesting a common mechanism of deletion formation. However, an ongoing debate over the mechanism by which mtDNA replicates has made it difficult to develop clear and testable models for how mtDNA rearrangements arise and propagate at a molecular and cellular level. These deletions may impair energy metabolism if present in a high proportion of the mtDNA copies within the cell, and can be seen in primary mitochondrial diseases, either in sporadic cases or caused by autosomal variants in nuclear-encoded mtDNA maintenance genes. These mitochondrial diseases have diverse genetic causes and multiple modes of inheritance, and show notoriously broad clinical heterogeneity with complex tissue specificities, which further makes establishing genotype-phenotype relationships challenging. In this review, we aim to cover our current understanding of how the human mitochondrial genome is replicated, the mechanisms by which mtDNA replication and repair can lead to mtDNA instability in the form of large-scale rearrangements, how rearranged mtDNAs subsequently accumulate within cells, and the pathological consequences when this occurs.
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Affiliation(s)
- Tiago M Bernardino Gomes
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- NHS England Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne NE2 4HH, U.K
| | - Amy E Vincent
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
| | - Katja E Menger
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
| | - James B Stewart
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
| | - Thomas J Nicholls
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
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4
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Neueder A, Kojer K, Gu Z, Wang Y, Hering T, Tabrizi S, Taanman JW, Orth M. Huntington's disease affects mitochondrial network dynamics predisposing to pathogenic mitochondrial DNA mutations. Brain 2024; 147:2009-2022. [PMID: 38195181 DOI: 10.1093/brain/awae007] [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: 07/23/2023] [Revised: 09/27/2023] [Accepted: 12/11/2023] [Indexed: 01/11/2024] Open
Abstract
Huntington's disease (HD) predominantly affects the brain, causing a mixed movement disorder, cognitive decline and behavioural abnormalities. It also causes a peripheral phenotype involving skeletal muscle. Mitochondrial dysfunction has been reported in tissues of HD models, including skeletal muscle, and lymphoblast and fibroblast cultures from patients with HD. Mutant huntingtin protein (mutHTT) expression can impair mitochondrial quality control and accelerate mitochondrial ageing. Here, we obtained fresh human skeletal muscle, a post-mitotic tissue expressing the mutated HTT allele at physiological levels since birth, and primary cell lines from HTT CAG repeat expansion mutation carriers and matched healthy volunteers to examine whether such a mitochondrial phenotype exists in human HD. Using ultra-deep mitochondrial DNA (mtDNA) sequencing, we showed an accumulation of mtDNA mutations affecting oxidative phosphorylation. Tissue proteomics indicated impairments in mtDNA maintenance with increased mitochondrial biogenesis of less efficient oxidative phosphorylation (lower complex I and IV activity). In full-length mutHTT expressing primary human cell lines, fission-inducing mitochondrial stress resulted in normal mitophagy. In contrast, expression of high levels of N-terminal mutHTT fragments promoted mitochondrial fission and resulted in slower, less dynamic mitophagy. Expression of high levels of mutHTT fragments due to somatic nuclear HTT CAG instability can thus affect mitochondrial network dynamics and mitophagy, leading to pathogenic mtDNA mutations. We show that life-long expression of mutant HTT causes a mitochondrial phenotype indicative of mtDNA instability in fresh post-mitotic human skeletal muscle. Thus, genomic instability may not be limited to nuclear DNA, where it results in somatic expansion of the HTT CAG repeat length in particularly vulnerable cells such as striatal neurons. In addition to efforts targeting the causative mutation, promoting mitochondrial health may be a complementary strategy in treating diseases with DNA instability such as HD.
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Affiliation(s)
| | - Kerstin Kojer
- Department of Neurology, Ulm University, 89081 Ulm, Germany
| | - Zhenglong Gu
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Yiqin Wang
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Tanja Hering
- Department of Neurology, Ulm University, 89081 Ulm, Germany
| | - Sarah Tabrizi
- UCL Huntington's Disease Centre, UCL Queen Square Institute of Neurology and National Hospital for Neurology and Neurosurgery, London WC1N 3BG, UK
- Dementia Research Institute at UCL, London WC1N 3BG, UK
| | - Jan-Willem Taanman
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London NW3 2PF, UK
| | - Michael Orth
- Department of Neurology, Ulm University, 89081 Ulm, Germany
- Swiss Huntington Centre, Siloah AG, 3073 Gümligen, Switzerland
- University Hospital of Old Age Psychiatry and Psychotherapy, Bern University, CH-3000 Bern 60, Switzerland
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5
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Yan W, Xie C, Sun S, Zheng Q, Wang J, Wang Z, Man CH, Wang H, Yang Y, Wang T, Shi L, Zhang S, Huang C, Xu S, Wang YP. SUCLG1 restricts POLRMT succinylation to enhance mitochondrial biogenesis and leukemia progression. EMBO J 2024; 43:2337-2367. [PMID: 38649537 PMCID: PMC11183053 DOI: 10.1038/s44318-024-00101-9] [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: 09/27/2023] [Revised: 03/21/2024] [Accepted: 03/22/2024] [Indexed: 04/25/2024] Open
Abstract
Mitochondria are cellular powerhouses that generate energy through the electron transport chain (ETC). The mitochondrial genome (mtDNA) encodes essential ETC proteins in a compartmentalized manner, however, the mechanism underlying metabolic regulation of mtDNA function remains unknown. Here, we report that expression of tricarboxylic acid cycle enzyme succinate-CoA ligase SUCLG1 strongly correlates with ETC genes across various TCGA cancer transcriptomes. Mechanistically, SUCLG1 restricts succinyl-CoA levels to suppress the succinylation of mitochondrial RNA polymerase (POLRMT). Lysine 622 succinylation disrupts the interaction of POLRMT with mtDNA and mitochondrial transcription factors. SUCLG1-mediated POLRMT hyposuccinylation maintains mtDNA transcription, mitochondrial biogenesis, and leukemia cell proliferation. Specifically, leukemia-promoting FMS-like tyrosine kinase 3 (FLT3) mutations modulate nuclear transcription and upregulate SUCLG1 expression to reduce succinyl-CoA and POLRMT succinylation, resulting in enhanced mitobiogenesis. In line, genetic depletion of POLRMT or SUCLG1 significantly delays disease progression in mouse and humanized leukemia models. Importantly, succinyl-CoA level and POLRMT succinylation are downregulated in FLT3-mutated clinical leukemia samples, linking enhanced mitobiogenesis to cancer progression. Together, SUCLG1 connects succinyl-CoA with POLRMT succinylation to modulate mitochondrial function and cancer development.
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Affiliation(s)
- Weiwei Yan
- Precision Research Center for Refractory Diseases, Institute for Clinical Research, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
| | - Chengmei Xie
- Precision Research Center for Refractory Diseases, Institute for Clinical Research, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
| | - Sijun Sun
- Precision Research Center for Refractory Diseases, Institute for Clinical Research, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
- Department of Gastrointestinal Surgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
| | - Quan Zheng
- Center for Single-Cell Omics, School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Jingyi Wang
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
| | - Zihao Wang
- Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, 200032, Shanghai, China
| | - Cheuk-Him Man
- Division of Haematology, Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Haiyan Wang
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
| | - Yunfan Yang
- Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, 250012, Jinan, China
| | - Tianshi Wang
- Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of Medicine, 200025, Shanghai, China
| | - Leilei Shi
- Precision Research Center for Refractory Diseases, Institute for Clinical Research, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
| | - Shengjie Zhang
- Precision Research Center for Refractory Diseases, Institute for Clinical Research, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China.
| | - Chen Huang
- Department of Gastrointestinal Surgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China.
| | - Shuangnian Xu
- Department of Hematology, Southwest Hospital, Army Medical University, 400038, Chongqing, China.
| | - Yi-Ping Wang
- Precision Research Center for Refractory Diseases, Institute for Clinical Research, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China.
- Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, 200032, Shanghai, China.
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6
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Roux CJ, Dufeu-Berat CM, Hully M, Rotig A, Schiff M, De Lonlay P, Aubart M, Alison M, Jaroussie M, Levy R, Dangouloff-Ros V, Barcia G, Desguerre I, Munnich A, Gitiaux C, Boddaert N. Polyradiculoneuritis on MRI: An Overlooked Feature of Biallelic POLG Gene Mutations in Infancy. Neurology 2024; 102:e209356. [PMID: 38754044 DOI: 10.1212/wnl.0000000000209356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024] Open
Affiliation(s)
- Charles-Joris Roux
- From the Departments of Pediatric Radiology (C.-J.R., R.L., V.D.-R., N.B.), Neurology and Metabolism (C.-M.D.-B., M.H., M.S., P.D.L., M. Aubart, I.D., A.M., C.G.), and Genetics (A.R., G.B.), Hôpital Necker-Enfants Malades, AP-HP, Université Paris Cité; IMAGINE Institute INSERM UMR 1163 (C.-J.R., A.R., M.S., M. Aubart, R.L., V.D.-R., G.B., A.M., N.B.), Paris; INSERM Institut Necker-Enfants Malades (P.D.L.), Paris; and Departments of Pediatric Radiology (M. Alison) and Neurology (M.J.), Hospital Robert Debré, Université Paris Cité, France
| | - Claire-Marine Dufeu-Berat
- From the Departments of Pediatric Radiology (C.-J.R., R.L., V.D.-R., N.B.), Neurology and Metabolism (C.-M.D.-B., M.H., M.S., P.D.L., M. Aubart, I.D., A.M., C.G.), and Genetics (A.R., G.B.), Hôpital Necker-Enfants Malades, AP-HP, Université Paris Cité; IMAGINE Institute INSERM UMR 1163 (C.-J.R., A.R., M.S., M. Aubart, R.L., V.D.-R., G.B., A.M., N.B.), Paris; INSERM Institut Necker-Enfants Malades (P.D.L.), Paris; and Departments of Pediatric Radiology (M. Alison) and Neurology (M.J.), Hospital Robert Debré, Université Paris Cité, France
| | - Marie Hully
- From the Departments of Pediatric Radiology (C.-J.R., R.L., V.D.-R., N.B.), Neurology and Metabolism (C.-M.D.-B., M.H., M.S., P.D.L., M. Aubart, I.D., A.M., C.G.), and Genetics (A.R., G.B.), Hôpital Necker-Enfants Malades, AP-HP, Université Paris Cité; IMAGINE Institute INSERM UMR 1163 (C.-J.R., A.R., M.S., M. Aubart, R.L., V.D.-R., G.B., A.M., N.B.), Paris; INSERM Institut Necker-Enfants Malades (P.D.L.), Paris; and Departments of Pediatric Radiology (M. Alison) and Neurology (M.J.), Hospital Robert Debré, Université Paris Cité, France
| | - Agnes Rotig
- From the Departments of Pediatric Radiology (C.-J.R., R.L., V.D.-R., N.B.), Neurology and Metabolism (C.-M.D.-B., M.H., M.S., P.D.L., M. Aubart, I.D., A.M., C.G.), and Genetics (A.R., G.B.), Hôpital Necker-Enfants Malades, AP-HP, Université Paris Cité; IMAGINE Institute INSERM UMR 1163 (C.-J.R., A.R., M.S., M. Aubart, R.L., V.D.-R., G.B., A.M., N.B.), Paris; INSERM Institut Necker-Enfants Malades (P.D.L.), Paris; and Departments of Pediatric Radiology (M. Alison) and Neurology (M.J.), Hospital Robert Debré, Université Paris Cité, France
| | - Manuel Schiff
- From the Departments of Pediatric Radiology (C.-J.R., R.L., V.D.-R., N.B.), Neurology and Metabolism (C.-M.D.-B., M.H., M.S., P.D.L., M. Aubart, I.D., A.M., C.G.), and Genetics (A.R., G.B.), Hôpital Necker-Enfants Malades, AP-HP, Université Paris Cité; IMAGINE Institute INSERM UMR 1163 (C.-J.R., A.R., M.S., M. Aubart, R.L., V.D.-R., G.B., A.M., N.B.), Paris; INSERM Institut Necker-Enfants Malades (P.D.L.), Paris; and Departments of Pediatric Radiology (M. Alison) and Neurology (M.J.), Hospital Robert Debré, Université Paris Cité, France
| | - Pascale De Lonlay
- From the Departments of Pediatric Radiology (C.-J.R., R.L., V.D.-R., N.B.), Neurology and Metabolism (C.-M.D.-B., M.H., M.S., P.D.L., M. Aubart, I.D., A.M., C.G.), and Genetics (A.R., G.B.), Hôpital Necker-Enfants Malades, AP-HP, Université Paris Cité; IMAGINE Institute INSERM UMR 1163 (C.-J.R., A.R., M.S., M. Aubart, R.L., V.D.-R., G.B., A.M., N.B.), Paris; INSERM Institut Necker-Enfants Malades (P.D.L.), Paris; and Departments of Pediatric Radiology (M. Alison) and Neurology (M.J.), Hospital Robert Debré, Université Paris Cité, France
| | - Mélodie Aubart
- From the Departments of Pediatric Radiology (C.-J.R., R.L., V.D.-R., N.B.), Neurology and Metabolism (C.-M.D.-B., M.H., M.S., P.D.L., M. Aubart, I.D., A.M., C.G.), and Genetics (A.R., G.B.), Hôpital Necker-Enfants Malades, AP-HP, Université Paris Cité; IMAGINE Institute INSERM UMR 1163 (C.-J.R., A.R., M.S., M. Aubart, R.L., V.D.-R., G.B., A.M., N.B.), Paris; INSERM Institut Necker-Enfants Malades (P.D.L.), Paris; and Departments of Pediatric Radiology (M. Alison) and Neurology (M.J.), Hospital Robert Debré, Université Paris Cité, France
| | - Marianne Alison
- From the Departments of Pediatric Radiology (C.-J.R., R.L., V.D.-R., N.B.), Neurology and Metabolism (C.-M.D.-B., M.H., M.S., P.D.L., M. Aubart, I.D., A.M., C.G.), and Genetics (A.R., G.B.), Hôpital Necker-Enfants Malades, AP-HP, Université Paris Cité; IMAGINE Institute INSERM UMR 1163 (C.-J.R., A.R., M.S., M. Aubart, R.L., V.D.-R., G.B., A.M., N.B.), Paris; INSERM Institut Necker-Enfants Malades (P.D.L.), Paris; and Departments of Pediatric Radiology (M. Alison) and Neurology (M.J.), Hospital Robert Debré, Université Paris Cité, France
| | - Marianne Jaroussie
- From the Departments of Pediatric Radiology (C.-J.R., R.L., V.D.-R., N.B.), Neurology and Metabolism (C.-M.D.-B., M.H., M.S., P.D.L., M. Aubart, I.D., A.M., C.G.), and Genetics (A.R., G.B.), Hôpital Necker-Enfants Malades, AP-HP, Université Paris Cité; IMAGINE Institute INSERM UMR 1163 (C.-J.R., A.R., M.S., M. Aubart, R.L., V.D.-R., G.B., A.M., N.B.), Paris; INSERM Institut Necker-Enfants Malades (P.D.L.), Paris; and Departments of Pediatric Radiology (M. Alison) and Neurology (M.J.), Hospital Robert Debré, Université Paris Cité, France
| | - Raphaël Levy
- From the Departments of Pediatric Radiology (C.-J.R., R.L., V.D.-R., N.B.), Neurology and Metabolism (C.-M.D.-B., M.H., M.S., P.D.L., M. Aubart, I.D., A.M., C.G.), and Genetics (A.R., G.B.), Hôpital Necker-Enfants Malades, AP-HP, Université Paris Cité; IMAGINE Institute INSERM UMR 1163 (C.-J.R., A.R., M.S., M. Aubart, R.L., V.D.-R., G.B., A.M., N.B.), Paris; INSERM Institut Necker-Enfants Malades (P.D.L.), Paris; and Departments of Pediatric Radiology (M. Alison) and Neurology (M.J.), Hospital Robert Debré, Université Paris Cité, France
| | - Volodia Dangouloff-Ros
- From the Departments of Pediatric Radiology (C.-J.R., R.L., V.D.-R., N.B.), Neurology and Metabolism (C.-M.D.-B., M.H., M.S., P.D.L., M. Aubart, I.D., A.M., C.G.), and Genetics (A.R., G.B.), Hôpital Necker-Enfants Malades, AP-HP, Université Paris Cité; IMAGINE Institute INSERM UMR 1163 (C.-J.R., A.R., M.S., M. Aubart, R.L., V.D.-R., G.B., A.M., N.B.), Paris; INSERM Institut Necker-Enfants Malades (P.D.L.), Paris; and Departments of Pediatric Radiology (M. Alison) and Neurology (M.J.), Hospital Robert Debré, Université Paris Cité, France
| | - Giulia Barcia
- From the Departments of Pediatric Radiology (C.-J.R., R.L., V.D.-R., N.B.), Neurology and Metabolism (C.-M.D.-B., M.H., M.S., P.D.L., M. Aubart, I.D., A.M., C.G.), and Genetics (A.R., G.B.), Hôpital Necker-Enfants Malades, AP-HP, Université Paris Cité; IMAGINE Institute INSERM UMR 1163 (C.-J.R., A.R., M.S., M. Aubart, R.L., V.D.-R., G.B., A.M., N.B.), Paris; INSERM Institut Necker-Enfants Malades (P.D.L.), Paris; and Departments of Pediatric Radiology (M. Alison) and Neurology (M.J.), Hospital Robert Debré, Université Paris Cité, France
| | - Isabelle Desguerre
- From the Departments of Pediatric Radiology (C.-J.R., R.L., V.D.-R., N.B.), Neurology and Metabolism (C.-M.D.-B., M.H., M.S., P.D.L., M. Aubart, I.D., A.M., C.G.), and Genetics (A.R., G.B.), Hôpital Necker-Enfants Malades, AP-HP, Université Paris Cité; IMAGINE Institute INSERM UMR 1163 (C.-J.R., A.R., M.S., M. Aubart, R.L., V.D.-R., G.B., A.M., N.B.), Paris; INSERM Institut Necker-Enfants Malades (P.D.L.), Paris; and Departments of Pediatric Radiology (M. Alison) and Neurology (M.J.), Hospital Robert Debré, Université Paris Cité, France
| | - Arnold Munnich
- From the Departments of Pediatric Radiology (C.-J.R., R.L., V.D.-R., N.B.), Neurology and Metabolism (C.-M.D.-B., M.H., M.S., P.D.L., M. Aubart, I.D., A.M., C.G.), and Genetics (A.R., G.B.), Hôpital Necker-Enfants Malades, AP-HP, Université Paris Cité; IMAGINE Institute INSERM UMR 1163 (C.-J.R., A.R., M.S., M. Aubart, R.L., V.D.-R., G.B., A.M., N.B.), Paris; INSERM Institut Necker-Enfants Malades (P.D.L.), Paris; and Departments of Pediatric Radiology (M. Alison) and Neurology (M.J.), Hospital Robert Debré, Université Paris Cité, France
| | - Cyril Gitiaux
- From the Departments of Pediatric Radiology (C.-J.R., R.L., V.D.-R., N.B.), Neurology and Metabolism (C.-M.D.-B., M.H., M.S., P.D.L., M. Aubart, I.D., A.M., C.G.), and Genetics (A.R., G.B.), Hôpital Necker-Enfants Malades, AP-HP, Université Paris Cité; IMAGINE Institute INSERM UMR 1163 (C.-J.R., A.R., M.S., M. Aubart, R.L., V.D.-R., G.B., A.M., N.B.), Paris; INSERM Institut Necker-Enfants Malades (P.D.L.), Paris; and Departments of Pediatric Radiology (M. Alison) and Neurology (M.J.), Hospital Robert Debré, Université Paris Cité, France
| | - Nathalie Boddaert
- From the Departments of Pediatric Radiology (C.-J.R., R.L., V.D.-R., N.B.), Neurology and Metabolism (C.-M.D.-B., M.H., M.S., P.D.L., M. Aubart, I.D., A.M., C.G.), and Genetics (A.R., G.B.), Hôpital Necker-Enfants Malades, AP-HP, Université Paris Cité; IMAGINE Institute INSERM UMR 1163 (C.-J.R., A.R., M.S., M. Aubart, R.L., V.D.-R., G.B., A.M., N.B.), Paris; INSERM Institut Necker-Enfants Malades (P.D.L.), Paris; and Departments of Pediatric Radiology (M. Alison) and Neurology (M.J.), Hospital Robert Debré, Université Paris Cité, France
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7
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Li W, Li Y, Zhao J, Liao J, Wen W, Chen Y, Cui H. Release of damaged mitochondrial DNA: A novel factor in stimulating inflammatory response. Pathol Res Pract 2024; 258:155330. [PMID: 38733868 DOI: 10.1016/j.prp.2024.155330] [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: 12/28/2023] [Revised: 04/03/2024] [Accepted: 04/23/2024] [Indexed: 05/13/2024]
Abstract
Mitochondrial DNA (mtDNA) is a circular double-stranded genome that exists independently of the nucleus. In recent years, research on mtDNA has significantly increased, leading to a gradual increase in understanding of its physiological and pathological characteristics. Reactive oxygen species (ROS) and other factors can damage mtDNA. This damaged mtDNA can escape from the mitochondria to the cytoplasm or extracellular space, subsequently activating immune signaling pathways, such as NLR family pyrin domain protein 3 (NLRP3), and triggering inflammatory responses. Numerous studies have demonstrated the involvement of mtDNA damage and leakage in the pathological mechanisms underlying various diseases including infectious diseases, metabolic inflammation, and immune disorders. Consequently, comprehensive investigation of mtDNA can elucidate the pathological mechanisms underlying numerous diseases. The prevention of mtDNA damage and leakage has emerged as a novel approach to disease treatment, and mtDNA has emerged as a promising target for drug development. This article provides a comprehensive review of the mechanisms underlying mtDNA-induced inflammation, its association with various diseases, and the methods used for its detection.
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Affiliation(s)
- Wenting Li
- The First School of Clinical Medicine, Yunnan University of Chinese Medicine, Yunnan 650500, China
| | - Yuting Li
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin 300193, China
| | - Jie Zhao
- Department of TCM Endocrinology, Yunnan Provincial Hospital of Traditional Chinese Medicine, Yunnan 650021, China
| | - Jiabao Liao
- The First School of Clinical Medicine, Yunnan University of Chinese Medicine, Yunnan 650500, China
| | - Weibo Wen
- The First School of Clinical Medicine, Yunnan University of Chinese Medicine, Yunnan 650500, China.
| | - Yao Chen
- Department of TCM Encephalopathy, Yunnan Provincial Hospital of Traditional Chinese Medicine, Yunnan 650021, China.
| | - Huantian Cui
- The First School of Clinical Medicine, Yunnan University of Chinese Medicine, Yunnan 650500, China.
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8
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Liu Y, Yang H, Gan S, He L, Zeng R, Xiao T, Wu L. A novel mutation of DNA2 regulates neuronal cell membrane potential and epileptogenesis. Cell Death Discov 2024; 10:259. [PMID: 38802339 PMCID: PMC11130173 DOI: 10.1038/s41420-024-02029-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 04/28/2024] [Accepted: 05/14/2024] [Indexed: 05/29/2024] Open
Abstract
Mesial temporal lobe epilepsy (MTLE) is one of the most intractable epilepsies. Previously, we reported that mitochondrial DNA deletions were associated with epileptogenesis. While the underlying mechanism of mitochondrial DNA deletions during epileptogenesis remain unknown. In this study, a novel somatic mutation of DNA2 gene was identified in the hippocampal tissue of two MTLE patients carrying mitochondrial DNA deletions, and this mutation decreased the full-length expression of DNA2 protein significantly, aborting its normal functions. Then, we knocked down the DNA2 protein in zebrafish, and we demonstrated that zebrafish with DNA2 deficiency showed decreased expression of mitochondrial complex II-IV, and exhibited hallmarks of epileptic seizures, including abnormal development of the zebrafish and epileptiform discharge signals in brain, compared to the Cas9-control group. Moreover, our cell-based assays showed that DNA2 deletion resulted in accumulated mitochondrial DNA damage, abnormal oxidative phosphorylation and decreased ATP production in cells. Inadequate ATP generation in cells lead to declined Na+, K+-ATPase activity and change of cell membrane potential. Together, these disorders caused by DNA2 depletion increased cell apoptosis and inhibited the differentiation of SH-SY5Y into branched neuronal phenotype. In conclusion, DNA2 deficiency regulated the cell membrane potential via affecting ATP production by mitochondria and Na+, K+-ATPase activity, and also affected neuronal cell growth and differentiation. These disorders caused by DNA2 dysfunction are important causes of epilepsy. In summary, we are the first to report the pathogenic somatic mutation of DNA2 gene in the patients with MTLE disease, and we uncovered the mechanism of DNA2 regulating the epilepsy. This study provides new insight into the pathogenesis of epilepsy and underscore the value of DNA2 in epilepsy.
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Affiliation(s)
- Yuting Liu
- Pediatrics Research Institute, The Affiliated Children's Hospital of Xiangya School of Medicine, Hunan Children's Hospital, Central South University, Changsha, Hunan, China
| | - Haiyan Yang
- Department of Neurology, The Affiliated Children's Hospital of Xiangya School of Medicine, Hunan Children's Hospital, Central South University, Changsha, Hunan, China
| | - Siyi Gan
- Department of Neurology, The Affiliated Children's Hospital of Xiangya School of Medicine, Hunan Children's Hospital, Central South University, Changsha, Hunan, China
| | - Lu He
- Department of Neurology, The Affiliated Children's Hospital of Xiangya School of Medicine, Hunan Children's Hospital, Central South University, Changsha, Hunan, China
| | - Rongrong Zeng
- Department of Neurology, The Affiliated Children's Hospital of Xiangya School of Medicine, Hunan Children's Hospital, Central South University, Changsha, Hunan, China
| | - Ting Xiao
- Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Liwen Wu
- Department of Neurology, The Affiliated Children's Hospital of Xiangya School of Medicine, Hunan Children's Hospital, Central South University, Changsha, Hunan, China.
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9
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VanPortfliet JJ, Lei Y, Martinez CG, Wong J, Pflug K, Sitcheran R, Kneeland SC, Murray SA, McGuire PJ, Cannon CL, West AP. Caspase-11 drives macrophage hyperinflammation in models of Polg-related mitochondrial disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.11.593693. [PMID: 38798587 PMCID: PMC11118447 DOI: 10.1101/2024.05.11.593693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Mitochondrial diseases (MtD) represent a significant public health challenge due to their heterogenous clinical presentation, often severe and progressive symptoms, and the lack of effective therapies. Environmental exposures, such bacterial and viral infection, can further compromise mitochondrial function and exacerbate the progression of MtD. Infections in MtD patients more frequently progress to sepsis, pneumonia, and other detrimental inflammatory endpoints. However, the underlying immune alterations that enhance immunopathology in MtD remain unclear, constituting a key gap in knowledge that complicates treatment and increases mortality in this population. Here we employ in vitro and in vivo approaches to clarify the molecular and cellular basis for innate immune hyperactivity in models of polymerase gamma (Polg)-related MtD. We reveal that type I interferon (IFN-I)-mediated upregulation of caspase-11 and guanylate-binding proteins (GBPs) increase macrophage sensing of the opportunistic microbe Pseudomonas aeruginosa (PA) in Polg mutant mice. Furthermore, we show that excessive macrophage cytokine secretion and pyroptotic cell death contribute to lung inflammation and morbidity after infection with PA. Our work sheds new light on innate immune dysregulation in MtD and reveals potential targets for limiting infection- and inflammation-related complications in Polg-related MtD.
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Affiliation(s)
- Jordyn J. VanPortfliet
- The Jackson Laboratory, Bar Harbor, Maine 04609, USA
- Department of Microbial Pathogenesis and Immunology, School of Medicine, Texas A&M University, Bryan, Texas 77807, USA
| | - Yuanjiu Lei
- Department of Microbial Pathogenesis and Immunology, School of Medicine, Texas A&M University, Bryan, Texas 77807, USA
- Department of Pathology, Yale School of Medicine, New Haven, CT 06520, USA
| | - Camila Guerra Martinez
- Department of Microbial Pathogenesis and Immunology, School of Medicine, Texas A&M University, Bryan, Texas 77807, USA
| | - Jessica Wong
- The Jackson Laboratory, Bar Harbor, Maine 04609, USA
| | - Kathryn Pflug
- Department of Cell Biology and Genetics, School of Medicine, Texas A&M University, Bryan, Texas 77807, USA
| | - Raquel Sitcheran
- Department of Cell Biology and Genetics, School of Medicine, Texas A&M University, Bryan, Texas 77807, USA
| | | | | | - Peter. J. McGuire
- Metabolism, Infection and Immunity Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, 20892, USA
| | - Carolyn L. Cannon
- Department of Microbial Pathogenesis and Immunology, School of Medicine, Texas A&M University, Bryan, Texas 77807, USA
| | - A. Phillip West
- The Jackson Laboratory, Bar Harbor, Maine 04609, USA
- Department of Microbial Pathogenesis and Immunology, School of Medicine, Texas A&M University, Bryan, Texas 77807, USA
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10
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VanPortfliet JJ, Chute C, Lei Y, Shutt TE, West AP. Mitochondrial DNA release and sensing in innate immune responses. Hum Mol Genet 2024; 33:R80-R91. [PMID: 38779772 PMCID: PMC11112387 DOI: 10.1093/hmg/ddae031] [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: 01/27/2024] [Accepted: 02/09/2024] [Indexed: 05/25/2024] Open
Abstract
Mitochondria are pleiotropic organelles central to an array of cellular pathways including metabolism, signal transduction, and programmed cell death. Mitochondria are also key drivers of mammalian immune responses, functioning as scaffolds for innate immune signaling, governing metabolic switches required for immune cell activation, and releasing agonists that promote inflammation. Mitochondrial DNA (mtDNA) is a potent immunostimulatory agonist, triggering pro-inflammatory and type I interferon responses in a host of mammalian cell types. Here we review recent advances in how mtDNA is detected by nucleic acid sensors of the innate immune system upon release into the cytoplasm and extracellular space. We also discuss how the interplay between mtDNA release and sensing impacts cellular innate immune endpoints relevant to health and disease.
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Affiliation(s)
- Jordyn J VanPortfliet
- The Jackson Laboratory, Bar Harbor, ME 04609, United States
- Department of Microbial Pathogenesis and Immunology, School of Medicine, Texas A&M University, Bryan, TX 77807, United States
| | - Cole Chute
- Departments of Medical Genetics and Biochemistry & Molecular Biology, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Yuanjiu Lei
- Department of Pathology, Yale School of Medicine, New Haven, CT 06520, United States
| | - Timothy E Shutt
- Departments of Medical Genetics and Biochemistry & Molecular Biology, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - A Phillip West
- The Jackson Laboratory, Bar Harbor, ME 04609, United States
- Department of Microbial Pathogenesis and Immunology, School of Medicine, Texas A&M University, Bryan, TX 77807, United States
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11
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Koludarova L, Battersby BJ. Mitochondrial protein synthesis quality control. Hum Mol Genet 2024; 33:R53-R60. [PMID: 38280230 PMCID: PMC11112378 DOI: 10.1093/hmg/ddae012] [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: 12/06/2023] [Accepted: 01/05/2023] [Indexed: 01/29/2024] Open
Abstract
Human mitochondrial DNA is one of the most simplified cellular genomes and facilitates compartmentalized gene expression. Within the organelle, there is no physical barrier to separate transcription and translation, nor is there evidence that quality control surveillance pathways are active to prevent translation on faulty mRNA transcripts. Mitochondrial ribosomes synthesize 13 hydrophobic proteins that require co-translational insertion into the inner membrane of the organelle. To maintain the integrity of the inner membrane, which is essential for organelle function, requires responsive quality control mechanisms to recognize aberrations in protein synthesis. In this review, we explore how defects in mitochondrial protein synthesis can arise due to the culmination of inherent mistakes that occur throughout the steps of gene expression. In turn, we examine the stepwise series of quality control processes that are needed to eliminate any mistakes that would perturb organelle homeostasis. We aim to provide an integrated view on the quality control mechanisms of mitochondrial protein synthesis and to identify promising avenues for future research.
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Affiliation(s)
- Lidiia Koludarova
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki 00014, Finland
| | - Brendan J Battersby
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki 00014, Finland
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12
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Liang KX, Chen A, Kianian A, Kristiansen CK, Yangzom T, Furriol J, Høyland LE, Ziegler M, Kråkenes T, Tzoulis C, Fang EF, Sullivan GJ, Bindoff LA. Activation of Neurotoxic Astrocytes Due to Mitochondrial Dysfunction Triggered by POLG Mutation. Int J Biol Sci 2024; 20:2860-2880. [PMID: 38904024 PMCID: PMC11186360 DOI: 10.7150/ijbs.93445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 05/03/2024] [Indexed: 06/22/2024] Open
Abstract
Mitochondrial diseases are associated with neuronal death and mtDNA depletion. Astrocytes respond to injury or stimuli and damage to the central nervous system. Neurodegeneration can cause astrocytes to activate and acquire toxic functions that induce neuronal death. However, astrocyte activation and its impact on neuronal homeostasis in mitochondrial disease remain to be explored. Using patient cells carrying POLG mutations, we generated iPSCs and then differentiated these into astrocytes. POLG astrocytes exhibited mitochondrial dysfunction including loss of mitochondrial membrane potential, energy failure, loss of complex I and IV, disturbed NAD+/NADH metabolism, and mtDNA depletion. Further, POLG derived astrocytes presented an A1-like reactive phenotype with increased proliferation, invasion, upregulation of pathways involved in response to stimulus, immune system process, cell proliferation and cell killing. Under direct and indirect co-culture with neurons, POLG astrocytes manifested a toxic effect leading to the death of neurons. We demonstrate that mitochondrial dysfunction caused by POLG mutations leads not only to intrinsic defects in energy metabolism affecting both neurons and astrocytes, but also to neurotoxic damage driven by astrocytes. These findings reveal a novel role for dysfunctional astrocytes that contribute to the pathogenesis of POLG diseases.
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Affiliation(s)
- Kristina Xiao Liang
- Department of Clinical Medicine (K1), University of Bergen, Jonas Lies vei 87, P. O. Box 7804, 5021 Bergen, Norway
- Neuro-SysMed, Center of Excellence for Clinical Research in Neurological Diseases, Haukeland University Hospital, Jonas Lies vei 87, P. O. Box 7804, 5021 Bergen, Norway
| | - Anbin Chen
- Department of Clinical Medicine (K1), University of Bergen, Jonas Lies vei 87, P. O. Box 7804, 5021 Bergen, Norway
- Department of Neurosurgery, Xinhua Hospital Affiliated toShanghai Jiaotong University School of Medicine, No. 1665, Kongjiang Road, 200092 Shanghai, China
| | - Atefeh Kianian
- Department of Clinical Medicine (K1), University of Bergen, Jonas Lies vei 87, P. O. Box 7804, 5021 Bergen, Norway
| | - Cecilie Katrin Kristiansen
- Department of Clinical Medicine (K1), University of Bergen, Jonas Lies vei 87, P. O. Box 7804, 5021 Bergen, Norway
- Neuro-SysMed, Center of Excellence for Clinical Research in Neurological Diseases, Haukeland University Hospital, Jonas Lies vei 87, P. O. Box 7804, 5021 Bergen, Norway
| | - Tsering Yangzom
- Department of Clinical Medicine (K1), University of Bergen, Jonas Lies vei 87, P. O. Box 7804, 5021 Bergen, Norway
| | - Jessica Furriol
- Department of Clinical Medicine (K1), University of Bergen, Jonas Lies vei 87, P. O. Box 7804, 5021 Bergen, Norway
- Department of Medicine, Haukeland University Hospital, Jonas Lies vei 87, P. O. Box 7804, 5021 Bergen, Norway
| | - Lena Elise Høyland
- Department of Biomedicine, University of Bergen, Jonas Lies Vei 91, 5009 Bergen, Norway
| | - Mathias Ziegler
- Department of Biomedicine, University of Bergen, Jonas Lies Vei 91, 5009 Bergen, Norway
| | - Torbjørn Kråkenes
- Department of Clinical Medicine (K1), University of Bergen, Jonas Lies vei 87, P. O. Box 7804, 5021 Bergen, Norway
- Neuro-SysMed, Center of Excellence for Clinical Research in Neurological Diseases, Haukeland University Hospital, Jonas Lies vei 87, P. O. Box 7804, 5021 Bergen, Norway
| | - Charalampos Tzoulis
- Department of Clinical Medicine (K1), University of Bergen, Jonas Lies vei 87, P. O. Box 7804, 5021 Bergen, Norway
- Neuro-SysMed, Center of Excellence for Clinical Research in Neurological Diseases, Haukeland University Hospital, Jonas Lies vei 87, P. O. Box 7804, 5021 Bergen, Norway
| | - Evandro Fei Fang
- Department of Clinical Molecular Biology, University of Oslo and Akershus University Hospital, 1478 Oslo, Norway
- The Norwegian Centre on Healthy Ageing (NO-Age), 1478 Oslo, Norway
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, P. O. Box 1105, 0317 Oslo, Norway
| | - Gareth John Sullivan
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, P. O. Box 1105, 0317 Oslo, Norway
- Institute of Immunology, Oslo University Hospital, P.O. Box 4950, 0424 Oslo, Norway
- Hybrid Technology Hub Centre of Excellence, Institute of Basic Medical Sciences, University of Oslo, P. O. Box 1110, 0317 Oslo, Norway
- Department of Pediatric Research, Oslo University Hospital, P. O. Box 4950, 0424 Oslo, Norway
| | - Laurence A. Bindoff
- Department of Clinical Medicine (K1), University of Bergen, Jonas Lies vei 87, P. O. Box 7804, 5021 Bergen, Norway
- Neuro-SysMed, Center of Excellence for Clinical Research in Neurological Diseases, Haukeland University Hospital, Jonas Lies vei 87, P. O. Box 7804, 5021 Bergen, Norway
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13
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Saha D, Kothari S, Kulkarni SD, Thambiraja M, Yennamalli RM, Das DK. Genetic heterogeneity and respiratory chain enzyme analysis in pediatric Indian patients with mitochondrial disorder: Report of novel variants in POLG1 gene and their functional implication using molecular dynamic simulation. Mitochondrion 2024; 76:101870. [PMID: 38471579 DOI: 10.1016/j.mito.2024.101870] [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: 12/05/2023] [Revised: 03/04/2024] [Accepted: 03/07/2024] [Indexed: 03/14/2024]
Abstract
Mitochondrial disorders are a heterogeneous group of disorders caused by mutations in the mitochondrial DNA or in nuclear genes encoding the mitochondrial proteins and subunits. Polymerase Gamma (POLG) is a nuclear gene and mutation in the POLG gene are one of the major causes of inherited mitochondrial disorders. In this study, 15 pediatric patients, with a wide spectrum of clinical phenotypes were screened using blood samples (n = 15) and muscle samples (n = 4). Respiratory chain enzyme analysis in the muscle samples revealed multi-complex deficiencies with Complex I deficiency present in (1/4) patients, Complex II (2/4), Complex III (3/4) and Complex IV (2/4) patients. Multiple large deletions were observed in 4/15 patients using LR-PCR. Whole exome sequencing (WES) revealed a compound heterozygous mutation consisting of a POLG1 novel variant (NP_002684.1:p.Trp261X) and a missense variant (NP_002684.1:p. Leu304Arg) in one patient and another patient harboring a novel homozygous POLG1 variant (NP_002684.1:p. Phe750Val). These variants (NP_002684.1:p. Leu304Arg) and (NP_002684.1:p. Phe750Val) and their interactions with DNA were modelled using molecular docking and molecular dynamics (MD) simulation studies. The protein conformation was analyzed as root mean square deviation (RMSD), root mean square fluctuation (RMSF) which showed local fluctuations in the mutants compared to the wildtype. However, Solvent Accessible Surface Area (SASA) significantly increased for NP_002684.1:p.Leu304Arg and decreased in NP_002684.1:p.Phe750Val mutants. Further, Contact Order analysis indicated that the Aromatic-sulfur interactions were destabilizing in the mutants. Overall, these in-silico analysis has revealed a destabilizing mutations suggesting pathogenic variants in POLG1 gene.
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Affiliation(s)
- Debolina Saha
- Stem Cell Biology Department, ICMR-National Institute for Research in Reproductive and Child Health, JM Street, Parel, Mumbai 400012, India
| | - Sonam Kothari
- Department of Pediatric Neurology, Bai Jerbai Wadia Hospital for Children, Acharya Donde Marg, Parel, Mumbai, Maharashtra 400012, India
| | - Shilpa Duttaprasanna Kulkarni
- Department of Pediatric Neurology, Bai Jerbai Wadia Hospital for Children, Acharya Donde Marg, Parel, Mumbai, Maharashtra 400012, India
| | - Menaka Thambiraja
- Department of Bioinformatics, School of Chemical and Biotechnology, SASTRA Deemed to be University, Thanjavur, Tamilnadu 613401, India
| | - Ragothaman M Yennamalli
- Department of Bioinformatics, School of Chemical and Biotechnology, SASTRA Deemed to be University, Thanjavur, Tamilnadu 613401, India.
| | - Dhanjit K Das
- Stem Cell Biology Department, ICMR-National Institute for Research in Reproductive and Child Health, JM Street, Parel, Mumbai 400012, India.
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14
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Liang KX. The application of brain organoid for drug discovery in mitochondrial diseases. Int J Biochem Cell Biol 2024; 170:106556. [PMID: 38423381 DOI: 10.1016/j.biocel.2024.106556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 02/26/2024] [Accepted: 02/26/2024] [Indexed: 03/02/2024]
Abstract
Mitochondrial diseases are difficult to treat due to the complexity and multifaceted nature of mitochondrial dysfunction. Brain organoids are three-dimensional (3D) structures derived from human pluripotent stem cells designed to mimic brain-like development and function. Brain organoids have received a lot of attention in recent years as powerful tools for modeling human diseases, brain development, and drug screening. Screening compounds for mitochondrial diseases using brain organoids could provide a more physiologically relevant platform for drug discovery. Brain organoids offer the possibility of personalized medicine because they can be derived from patient-specific cells, allowing testing of drugs tailored to specific genetic mutations. In this article, we highlight how brain organoids offer a promising avenue for screening compounds for mitochondrial diseases and address the challenges and limitations associated with their use. We hope this review will provide new insights into the further progress of brain organoids for mitochondrial screening studies.
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Chen A, Yangzom T, Hong Y, Lundberg BC, Sullivan GJ, Tzoulis C, Bindoff LA, Liang KX. Hallmark Molecular and Pathological Features of POLG Disease are Recapitulated in Cerebral Organoids. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2307136. [PMID: 38445970 PMCID: PMC11095234 DOI: 10.1002/advs.202307136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 11/26/2023] [Indexed: 03/07/2024]
Abstract
In this research, a 3D brain organoid model is developed to study POLG-related encephalopathy, a mitochondrial disease stemming from POLG mutations. Induced pluripotent stem cells (iPSCs) derived from patients with these mutations is utilized to generate cortical organoids, which exhibited typical features of the diseases with POLG mutations, such as altered morphology, neuronal loss, and mitochondiral DNA (mtDNA) depletion. Significant dysregulation is also identified in pathways crucial for neuronal development and function, alongside upregulated NOTCH and JAK-STAT signaling pathways. Metformin treatment ameliorated many of these abnormalities, except for the persistent affliction of inhibitory dopamine-glutamate (DA GLU) neurons. This novel model effectively mirrors both the molecular and pathological attributes of diseases with POLG mutations, providing a valuable tool for mechanistic understanding and therapeutic screening for POLG-related disorders and other conditions characterized by compromised neuronal mtDNA maintenance and complex I deficiency.
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Affiliation(s)
- Anbin Chen
- Department of Clinical Medicine (K1)University of BergenBergen5021Norway
- Department of NeurosurgeryXinhua Hospital Affiliated to Shanghai Jiaotong University School of MedicineShanghai20092China
| | - Tsering Yangzom
- Department of Clinical Medicine (K1)University of BergenBergen5021Norway
- Centre for International HealthUniversity of BergenBergen5020Norway
| | - Yu Hong
- Department of Clinical Medicine (K1)University of BergenBergen5021Norway
| | - Bjørn Christian Lundberg
- Department of Clinical Medicine (K1)University of BergenBergen5021Norway
- Department of BiomedicineUniversity of BergenBergen5009Norway
| | | | - Charalampos Tzoulis
- Department of Clinical Medicine (K1)University of BergenBergen5021Norway
- Neuro‐SysMedCenter of Excellence for Clinical Research in Neurological DiseasesHaukeland University HospitalBergen5021Norway
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16
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Ramesh R, Amanmahanya C, Krishnamoorthy V, Krishnan V, Palani S, Narasimhan Ranganathan L. Oculomasticatory rhythmic movements, insomnia and stroke-like episodes in a patient with POLG mutation. BMJ Case Rep 2024; 17:e259426. [PMID: 38684350 PMCID: PMC11146406 DOI: 10.1136/bcr-2023-259426] [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: 04/19/2024] [Indexed: 05/02/2024] Open
Abstract
The POLG mutation, a leading cause of mitochondrial diseases, exhibits a wide-ranging age of onset and a complex clinical presentation. We encountered an atypical clinical profile in an elderly man with a POLG mutation, characterised by a stroke-like episode, chronic insomnia and transient oculomasticatory rhythmic movement. History revealed chronic constipation since his 50s and progressive bilateral ophthalmoplegia since his early 60s. Subsequently, he had experienced acute encephalopathy and later developed chronic insomnia. The present neurological examination showed bilateral complete ophthalmoplegia, ptosis, and rhythmic ocular and jaw movements. Imaging indicated findings suggestive of a stroke-like episode and eventual genetic analysis revealed a homozygous missense mutation in the POLG gene. This case expands the clinical spectrum of POLG mutations in individuals over 60 years, showcasing the rare combination of a stroke-like episode, chronic insomnia and oculomasticatory rhythmic movement.
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Affiliation(s)
- Rithvik Ramesh
- Neurology, Sri Ramachandra Institute of Higher Education and Research (Deemed to be University), Chennai, Tamil Nadu, India
| | - Chitneni Amanmahanya
- Neurology, Sri Ramachandra Institute of Higher Education and Research (Deemed to be University), Chennai, Tamil Nadu, India
| | - Vengadakrishnan Krishnamoorthy
- Internal Medicine, Sri Ramachandra Institute of Higher Education and Research (Deemed to be University), Chennai, Tamil Nadu, India
| | - Vasanthan Krishnan
- Internal Medicine, Sri Ramachandra Institute of Higher Education and Research (Deemed to be University), Chennai, Tamil Nadu, India
| | - Sathyamoorthy Palani
- Internal Medicine, Sri Ramachandra Institute of Higher Education and Research (Deemed to be University), Chennai, Tamil Nadu, India
| | - Lakshmi Narasimhan Ranganathan
- Neurology, Sri Ramachandra Institute of Higher Education and Research (Deemed to be University), Chennai, Tamil Nadu, India
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17
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Wang Y, Hang L, Shou W, Li C, Dong F, Feng X, Jin R, Li B, Xiao S. Case Report: A novel RRM2B variant in a Chinese infant with mitochondrial DNA depletion syndrome and collective analyses of RRM2B variants for disease etiology. Front Pediatr 2024; 12:1363728. [PMID: 38737634 PMCID: PMC11084280 DOI: 10.3389/fped.2024.1363728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Accepted: 04/10/2024] [Indexed: 05/14/2024] Open
Abstract
Background There are few reports of infantile mitochondrial DNA depletion syndrome (MDDS) caused by variants in RRM2B and the correlation between genotype and phenotype has rarely been analyzed in detail. This study investigated an infantile patient with MDDS, from clinical characteristics to genetic causes. Methods Routine physical examinations, laboratory assays, which included gas chromatography-mass spectrometry of blood and urine, and MRI scans were performed to obtain an exact diagnosis. Whole-exome sequencing was used to pinpoint the abnormal gene and bioinformatic analyses were performed on the identified variant. Results The case presented with progressive neurologic deterioration, failure to thrive, respiratory distress and lactic acidosis. Sequencing revealed that the patient had a homozygous novel missense variant, c.155T>C (p.Ile52Thr), in exon 2 of the RRM2B gene. Multiple lines of bioinformatic evidence suggested that this was a likely detrimental variant. In addition, reported RRM2B variants were compiled from the relevant literature to analyze disease etiology. We found a distinctive distribution of genotypes across disease manifestations of different severity. Pathogenic alleles of RRM2B were significantly enriched in MDDS cases. Conclusion The novel variant is a likely genetic cause of MDDS. It expands our understanding of the pathogenic variant spectrum and the contribution of the RRM2B gene to the disease spectrum of MDDS.
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Affiliation(s)
- Yanjun Wang
- Pediatric Intensive Care Unit, Kunming Children’s Hospital, Children’s Hospital Affiliated to Kunming Medical University, Kunming, China
| | - Ling Hang
- Pediatric Intensive Care Unit, Kunming Children’s Hospital, Children’s Hospital Affiliated to Kunming Medical University, Kunming, China
| | - Weihua Shou
- Kunming Key Laboratory of Children Infection and Immunity, Yunnan Key Laboratory of Children’s Major Disease Research, Yunnan Medical Center for Pediatric Diseases, Yunnan Institute of Pediatrics, Kunming Children’s Hospital, Kunming, China
| | - Cuifen Li
- Pediatric Intensive Care Unit, Kunming Children’s Hospital, Children’s Hospital Affiliated to Kunming Medical University, Kunming, China
| | - Fangling Dong
- Pediatric Intensive Care Unit, Kunming Children’s Hospital, Children’s Hospital Affiliated to Kunming Medical University, Kunming, China
| | - Xingxing Feng
- Department of Clinical Laboratory, Kunming Children’s Hospital, Children’s Hospital Affiliated to Kunming Medical University, Kunming, China
| | - Ruohong Jin
- Pediatric Intensive Care Unit, Kunming Children’s Hospital, Children’s Hospital Affiliated to Kunming Medical University, Kunming, China
| | - Bin Li
- Pediatric Intensive Care Unit, Kunming Children’s Hospital, Children’s Hospital Affiliated to Kunming Medical University, Kunming, China
| | - Shufang Xiao
- Pediatric Intensive Care Unit, Kunming Children’s Hospital, Children’s Hospital Affiliated to Kunming Medical University, Kunming, China
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18
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Mao EYC, Yen HY, Wu CC. Structural basis of how MGME1 processes DNA 5' ends to maintain mitochondrial genome integrity. Nucleic Acids Res 2024; 52:4067-4078. [PMID: 38471810 DOI: 10.1093/nar/gkae186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 02/29/2024] [Accepted: 03/05/2024] [Indexed: 03/14/2024] Open
Abstract
Mitochondrial genome maintenance exonuclease 1 (MGME1) helps to ensure mitochondrial DNA (mtDNA) integrity by serving as an ancillary 5'-exonuclease for DNA polymerase γ. Curiously, MGME1 exhibits unique bidirectionality in vitro, being capable of degrading DNA from either the 5' or 3' end. The structural basis of this bidirectionally and, particularly, how it processes DNA from the 5' end to assist in mtDNA maintenance remain unclear. Here, we present a crystal structure of human MGME1 in complex with a 5'-overhang DNA, revealing that MGME1 functions as a rigid DNA clamp equipped with a single-strand (ss)-selective arch, allowing it to slide on single-stranded DNA in either the 5'-to-3' or 3'-to-5' direction. Using a nuclease activity assay, we have dissected the structural basis of MGME1-derived DNA cleavage patterns in which the arch serves as a ruler to determine the cleavage site. We also reveal that MGME1 displays partial DNA-unwinding ability that helps it to better resolve 5'-DNA flaps, providing insights into MGME1-mediated 5'-end processing of nascent mtDNA. Our study builds on previously solved MGME1-DNA complex structures, finally providing the comprehensive functional mechanism of this bidirectional, ss-specific exonuclease.
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Affiliation(s)
- Eric Y C Mao
- Department of Chemistry, College of Science, National Cheng Kung University, Tainan City 701, Taiwan
| | - Han-Yi Yen
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan City 701, Taiwan
| | - Chyuan-Chuan Wu
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan City 701, Taiwan
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19
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Magielski J, Ruggiero SM, Xian J, Parthasarathy S, Galer P, Ganesan S, Back A, McKee J, McSalley I, Gonzalez AK, Morgan A, Donaher J, Helbig I. The clinical and genetic spectrum of paediatric speech and language disorders in 52,143 individuals. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.04.23.24306192. [PMID: 38712155 PMCID: PMC11071575 DOI: 10.1101/2024.04.23.24306192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Speech and language disorders are known to have a substantial genetic contribution. Although frequently examined as components of other conditions, research on the genetic basis of linguistic differences as separate phenotypic subgroups has been limited so far. Here, we performed an in-depth characterization of speech and language disorders in 52,143 individuals, reconstructing clinical histories using a large-scale data mining approach of the Electronic Medical Records (EMR) from an entire large paediatric healthcare network. The reported frequency of these disorders was the highest between 2 and 5 years old and spanned a spectrum of twenty-six broad speech and language diagnoses. We used Natural Language Processing to assess to which degree clinical diagnosis in full-text notes were reflected in ICD-10 diagnosis codes. We found that aphasia and speech apraxia could be easily retrieved through ICD-10 diagnosis codes, while stuttering as a speech phenotype was only coded in 12% of individuals through appropriate ICD-10 codes. We found significant comorbidity of speech and language disorders in neurodevelopmental conditions (30.31%) and to a lesser degree with epilepsies (6.07%) and movement disorders (2.05%). The most common genetic disorders retrievable in our EMR analysis were STXBP1 (n=21), PTEN (n=20), and CACNA1A (n=18). When assessing associations of genetic diagnoses with specific linguistic phenotypes, we observed associations of STXBP1 and aphasia (P=8.57 × 10-7, CI=18.62-130.39) and MYO7A with speech and language development delay due to hearing loss (P=1.24 × 10-5, CI=17.46-Inf). Finally, in a sub-cohort of 726 individuals with whole exome sequencing data, we identified an enrichment of rare variants in synaptic protein and neuronal receptor pathways and associations of UQCRC1 with expressive aphasia and WASHC4 with abnormality of speech or vocalization. In summary, our study outlines the landscape of paediatric speech and language disorders, confirming the phenotypic complexity of linguistic traits and novel genotype-phenotype associations. Subgroups of paediatric speech and language disorders differ significantly with respect to the composition of monogenic aetiologies.
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Affiliation(s)
- Jan Magielski
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- The Epilepsy NeuroGenetics Initiative (ENGIN), Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Biomedical and Health Informatics (DBHi), Children’s Hospital of Philadelphia, Philadelphia, PA, 19146, USA
| | - Sarah M. Ruggiero
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- The Epilepsy NeuroGenetics Initiative (ENGIN), Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Julie Xian
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- The Epilepsy NeuroGenetics Initiative (ENGIN), Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Biomedical and Health Informatics (DBHi), Children’s Hospital of Philadelphia, Philadelphia, PA, 19146, USA
| | - Shridhar Parthasarathy
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- The Epilepsy NeuroGenetics Initiative (ENGIN), Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Biomedical and Health Informatics (DBHi), Children’s Hospital of Philadelphia, Philadelphia, PA, 19146, USA
| | - Peter Galer
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- The Epilepsy NeuroGenetics Initiative (ENGIN), Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Biomedical and Health Informatics (DBHi), Children’s Hospital of Philadelphia, Philadelphia, PA, 19146, USA
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Shiva Ganesan
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- The Epilepsy NeuroGenetics Initiative (ENGIN), Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Biomedical and Health Informatics (DBHi), Children’s Hospital of Philadelphia, Philadelphia, PA, 19146, USA
| | - Amanda Back
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- The Epilepsy NeuroGenetics Initiative (ENGIN), Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Jillian McKee
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- The Epilepsy NeuroGenetics Initiative (ENGIN), Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Biomedical and Health Informatics (DBHi), Children’s Hospital of Philadelphia, Philadelphia, PA, 19146, USA
- Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Ian McSalley
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- The Epilepsy NeuroGenetics Initiative (ENGIN), Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Biomedical and Health Informatics (DBHi), Children’s Hospital of Philadelphia, Philadelphia, PA, 19146, USA
| | - Alexander K. Gonzalez
- Department of Biomedical and Health Informatics (DBHi), Children’s Hospital of Philadelphia, Philadelphia, PA, 19146, USA
| | - Angela Morgan
- Murdoch Children’s Research Institute, Parkville 3052, Australia
- Department of Audiology and Speech Pathology, University of Melbourne, Parkville 3052, Australia
| | - Joseph Donaher
- Center for Childhood Communication, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Ingo Helbig
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- The Epilepsy NeuroGenetics Initiative (ENGIN), Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Biomedical and Health Informatics (DBHi), Children’s Hospital of Philadelphia, Philadelphia, PA, 19146, USA
- Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
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20
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Brañas Casas R, Zuppardo A, Risato G, Dinarello A, Celeghin R, Fontana C, Grelloni E, Gilea AI, Viscomi C, Rasola A, Dalla Valle L, Lodi T, Baruffini E, Facchinello N, Argenton F, Tiso N. Zebrafish polg2 knock-out recapitulates human POLG-disorders; implications for drug treatment. Cell Death Dis 2024; 15:281. [PMID: 38643274 PMCID: PMC11032366 DOI: 10.1038/s41419-024-06622-9] [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: 11/30/2023] [Revised: 03/15/2024] [Accepted: 03/18/2024] [Indexed: 04/22/2024]
Abstract
The human mitochondrial DNA polymerase gamma is a holoenzyme, involved in mitochondrial DNA (mtDNA) replication and maintenance, composed of a catalytic subunit (POLG) and a dimeric accessory subunit (POLG2) conferring processivity. Mutations in POLG or POLG2 cause POLG-related diseases in humans, leading to a subset of Mendelian-inherited mitochondrial disorders characterized by mtDNA depletion (MDD) or accumulation of multiple deletions, presenting multi-organ defects and often leading to premature death at a young age. Considering the paucity of POLG2 models, we have generated a stable zebrafish polg2 mutant line (polg2ia304) by CRISPR/Cas9 technology, carrying a 10-nucleotide deletion with frameshift mutation and premature stop codon. Zebrafish polg2 homozygous mutants present slower development and decreased viability compared to wild type siblings, dying before the juvenile stage. Mutants display a set of POLG-related phenotypes comparable to the symptoms of human patients affected by POLG-related diseases, including remarkable MDD, altered mitochondrial network and dynamics, and reduced mitochondrial respiration. Histological analyses detected morphological alterations in high-energy demanding tissues, along with a significant disorganization of skeletal muscle fibres. Consistent with the last finding, locomotor assays highlighted a decreased larval motility. Of note, treatment with the Clofilium tosylate drug, previously shown to be effective in POLG models, could partially rescue MDD in Polg2 mutant animals. Altogether, our results point at zebrafish as an effective model to study the etiopathology of human POLG-related disorders linked to POLG2, and a suitable platform to screen the efficacy of POLG-directed drugs in POLG2-associated forms.
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Affiliation(s)
| | - Alessandro Zuppardo
- Department of Biomedical Sciences, University of Padova, Padova, 35131, Italy
| | - Giovanni Risato
- Department of Biology, University of Padova, Padova, 35131, Italy
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padova, Padova, 35128, Italy
| | - Alberto Dinarello
- Department of Biology, University of Padova, Padova, 35131, Italy
- Novo Nordisk Foundation Center for Stem Cell Medicine (reNEW), University of Copenhagen, Copenhagen, 2200, Denmark
| | - Rudy Celeghin
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padova, Padova, 35128, Italy
| | - Camilla Fontana
- Department of Biology, University of Padova, Padova, 35131, Italy
- Department of Animal and Aquatic Sciences, Faculty of Agriculture, Chiang Mai University, Chiang Mai, 50200, Thailand
| | | | - Alexandru Ionut Gilea
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, 43124, Italy
| | - Carlo Viscomi
- Department of Biomedical Sciences, University of Padova, Padova, 35131, Italy
| | - Andrea Rasola
- Department of Biomedical Sciences, University of Padova, Padova, 35131, Italy
| | | | - Tiziana Lodi
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, 43124, Italy
| | - Enrico Baruffini
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, 43124, Italy
| | - Nicola Facchinello
- Neuroscience Institute, Italian Research Council (CNR), 35131, Padova, Italy.
| | | | - Natascia Tiso
- Department of Biology, University of Padova, Padova, 35131, Italy.
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21
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Romero VI, Sáenz S, Arias-Almeida B, DiCapua D, Hosomichi K. AARS and CACNA1A mutations: diagnostic insights into a case report of uncommon epileptic encephalopathy phenotypes in two siblings. Front Neurol 2024; 15:1376643. [PMID: 38689878 PMCID: PMC11059961 DOI: 10.3389/fneur.2024.1376643] [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: 01/25/2024] [Accepted: 04/04/2024] [Indexed: 05/02/2024] Open
Abstract
Epilepsy, characterized by recurrent seizures, impacts 70-80% of patients, leading to cognitive deficits. The intricate relationship between seizure control and cognitive impairment remains complex. Epileptic encephalopathy (EE), an intensified form often rooted in genetic factors, is detectable through next-generation sequencing, aiding in precise diagnoses, family counseling, and potential treatment strategies. We present a case involving two sisters with refractory generalized seizures evolving into dysarthria, dysphagia, ataxia, and cognitive decline. Despite normal physical exams, abnormal electroencephalogram results consistent with epilepsy were noted. Whole Exome Sequencing identified heterozygous variants in the alanyl-tRNA synthetase (AARS) and Calcium Voltage-Gated Channel Subunit Alpha 1 (CACNA1A) genes. The AARS variant (c.C2083T, p.R695*) was maternal, while the CACNA1A variant (c.G7400C, p.R2467P) was paternal. Patients A and B exhibited a unique blend of neurological and psychiatric conditions, distinct from common disorders that begin adolescence, like Juvenile Myoclonic Epilepsy. Whole Exome Sequencing uncovered an AARS gene and CACNA1A gene, linked to various autosomal dominant phenotypes. Presence in both parents, coupled with familial reports of migraines and seizures, provides insight into accelerated symptom progression. This study underscores the importance of genetic testing in decoding complex phenotypes and emphasizes the value of documenting family history for anticipating related symptoms and future health risks.
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Affiliation(s)
- Vanessa I. Romero
- School of Medicine, Universidad San Francisco de Quito, Quito, Ecuador
| | - Samantha Sáenz
- School of Medicine, Universidad San Francisco de Quito, Quito, Ecuador
| | | | - Daniela DiCapua
- School of Medicine, Universidad San Francisco de Quito, Quito, Ecuador
- Neurology Service, Hospital de Especialidades Eugenio Espejo, Quito, Ecuador
| | - Kazuyoshi Hosomichi
- Laboratory of Computational Genomics, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
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22
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Kang Y, Hepojoki J, Maldonado RS, Mito T, Terzioglu M, Manninen T, Kant R, Singh S, Othman A, Verma R, Uusimaa J, Wartiovaara K, Kareinen L, Zamboni N, Nyman TA, Paetau A, Kipar A, Vapalahti O, Suomalainen A. Ancestral allele of DNA polymerase gamma modifies antiviral tolerance. Nature 2024; 628:844-853. [PMID: 38570685 PMCID: PMC11041766 DOI: 10.1038/s41586-024-07260-z] [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: 02/27/2021] [Accepted: 02/29/2024] [Indexed: 04/05/2024]
Abstract
Mitochondria are critical modulators of antiviral tolerance through the release of mitochondrial RNA and DNA (mtDNA and mtRNA) fragments into the cytoplasm after infection, activating virus sensors and type-I interferon (IFN-I) response1-4. The relevance of these mechanisms for mitochondrial diseases remains understudied. Here we investigated mitochondrial recessive ataxia syndrome (MIRAS), which is caused by a common European founder mutation in DNA polymerase gamma (POLG1)5. Patients homozygous for the MIRAS variant p.W748S show exceptionally variable ages of onset and symptoms5, indicating that unknown modifying factors contribute to disease manifestation. We report that the mtDNA replicase POLG1 has a role in antiviral defence mechanisms to double-stranded DNA and positive-strand RNA virus infections (HSV-1, TBEV and SARS-CoV-2), and its p.W748S variant dampens innate immune responses. Our patient and knock-in mouse data show that p.W748S compromises mtDNA replisome stability, causing mtDNA depletion, aggravated by virus infection. Low mtDNA and mtRNA release into the cytoplasm and a slow IFN response in MIRAS offer viruses an early replicative advantage, leading to an augmented pro-inflammatory response, a subacute loss of GABAergic neurons and liver inflammation and necrosis. A population databank of around 300,000 Finnish individuals6 demonstrates enrichment of immunodeficient traits in carriers of the POLG1 p.W748S mutation. Our evidence suggests that POLG1 defects compromise antiviral tolerance, triggering epilepsy and liver disease. The finding has important implications for the mitochondrial disease spectrum, including epilepsy, ataxia and parkinsonism.
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MESH Headings
- Animals
- Female
- Humans
- Male
- Mice
- Age of Onset
- Alleles
- COVID-19/immunology
- COVID-19/virology
- COVID-19/genetics
- DNA Polymerase gamma/genetics
- DNA Polymerase gamma/immunology
- DNA Polymerase gamma/metabolism
- DNA, Mitochondrial/immunology
- DNA, Mitochondrial/metabolism
- Encephalitis Viruses, Tick-Borne/immunology
- Encephalitis, Tick-Borne/genetics
- Encephalitis, Tick-Borne/immunology
- Encephalitis, Tick-Borne/virology
- Founder Effect
- Gene Knock-In Techniques
- Herpes Simplex/genetics
- Herpes Simplex/immunology
- Herpes Simplex/virology
- Herpesvirus 1, Human/immunology
- Immune Tolerance/genetics
- Immune Tolerance/immunology
- Immunity, Innate/genetics
- Immunity, Innate/immunology
- Interferon Type I/immunology
- Mitochondrial Diseases/enzymology
- Mitochondrial Diseases/genetics
- Mitochondrial Diseases/immunology
- Mutation
- RNA, Mitochondrial/immunology
- RNA, Mitochondrial/metabolism
- SARS-CoV-2/immunology
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Affiliation(s)
- Yilin Kang
- Stem Cell and Metabolism Research Program Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Jussi Hepojoki
- Department of Virology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Laboratory for Animal Model Pathology, Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland
| | - Rocio Sartori Maldonado
- Stem Cell and Metabolism Research Program Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Takayuki Mito
- Stem Cell and Metabolism Research Program Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Mügen Terzioglu
- Stem Cell and Metabolism Research Program Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Tuula Manninen
- Stem Cell and Metabolism Research Program Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Ravi Kant
- Department of Virology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Department of Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
- Department of Tropical Parasitology, Institute of Maritime and Tropical Medicine, Medical University of Gdansk, Gdansk, Poland
| | - Sachin Singh
- Department of Immunology, Institute of Clinical Medicine, University of Oslo and Rikshospitalet Oslo, Oslo, Norway
| | - Alaa Othman
- Swiss Multi-Omics Center, ETH Zürich, Zürich, Switzerland
| | - Rohit Verma
- Stem Cell and Metabolism Research Program Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Johanna Uusimaa
- Research Unit of Clinical Medicine and Medical Research Center, University of Oulu, Oulu, Finland
- Department of Pediatrics and Adolescent Medicine, Unit of Child Neurology, Oulu University Hospital, Oulu, Finland
| | - Kirmo Wartiovaara
- Stem Cell and Metabolism Research Program Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Helsinki University Hospital, HUS Diagnostics, Helsinki, Finland
| | - Lauri Kareinen
- Department of Virology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Department of Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
- Finnish Food Safety Authority, Helsinki, Finland
| | - Nicola Zamboni
- Swiss Multi-Omics Center, ETH Zürich, Zürich, Switzerland
| | - Tuula Anneli Nyman
- Department of Immunology, Institute of Clinical Medicine, University of Oslo and Rikshospitalet Oslo, Oslo, Norway
| | - Anders Paetau
- Stem Cell and Metabolism Research Program Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Helsinki University Hospital, HUS Diagnostics, Helsinki, Finland
- Department of Pathology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Anja Kipar
- Laboratory for Animal Model Pathology, Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland
- Department of Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Olli Vapalahti
- Department of Virology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Department of Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
- Helsinki University Hospital, HUS Diagnostics, Helsinki, Finland
| | - Anu Suomalainen
- Stem Cell and Metabolism Research Program Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
- Helsinki University Hospital, HUS Diagnostics, Helsinki, Finland.
- HiLife, University of Helsinki, Helsinki, Finland.
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23
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Nica A. Drug-resistant juvenile myoclonic epilepsy: A literature review. Rev Neurol (Paris) 2024; 180:271-289. [PMID: 38461125 DOI: 10.1016/j.neurol.2024.02.385] [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: 11/18/2023] [Revised: 02/13/2024] [Accepted: 02/14/2024] [Indexed: 03/11/2024]
Abstract
The ILAE's Task Force on Nosology and Definitions revised in 2022 its definition of juvenile myoclonic epilepsy (JME), the most common idiopathic generalized epilepsy disorder, but this definition may well change again in the future. Although good drug response could almost be a diagnostic criterion for JME, drug resistance (DR) is observed in up to a third of patients. It is important to distinguish this from pseudoresistance, which is often linked to psychosocial problems or psychiatric comorbidities. After summarizing these aspects and the various definitions applied to JME, the present review lists the risk factors for DR-JME that have been identified in numerous studies and meta-analyses. The factors most often cited are absence seizures, young age at onset, and catamenial seizures. By contrast, photosensitivity seems to favor good treatment response, at least in female patients. Current hypotheses on DR mechanisms in JME are based on studies of either simple (e.g., cortical excitability) or more complex (e.g., anatomical and functional connectivity) neurophysiological markers, bearing in mind that JME is regarded as a neural network disease. This research has revealed correlations between the intensity of some markers and DR, and above all shed light on the role of these markers in associated neurocognitive and neuropsychiatric disorders in both patients and their siblings. Studies of neurotransmission have mainly pointed to impaired GABAergic inhibition. Genetic studies have generally been inconclusive. Increasing restrictions have been placed on the use of valproate, the standard antiseizure medication for this syndrome, owing to its teratogenic and developmental risks. Levetiracetam and lamotrigine are prescribed as alternatives, as is vagal nerve stimulation, and there are several other promising antiseizure drugs and neuromodulation methods. The development of better alternative treatments is continuing to take place alongside advances in our knowledge of JME, as we still have much to learn and understand.
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Affiliation(s)
- A Nica
- Epilepsy Unit, Reference Center for Rare Epilepsies, Neurology Department, Clinical Investigation Center 1414, Rennes University Hospital, Rennes, France; Signal and Image Processing Laboratory (LTSI), INSERM, Rennes University, Rennes, France.
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24
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Gonzalez CD, Nissanka N, Van Booven D, Griswold AJ, Moraes CT. Absence of both MGME1 and POLG EXO abolishes mtDNA whereas absence of either creates unique mtDNA duplications. J Biol Chem 2024; 300:107128. [PMID: 38432635 PMCID: PMC11002302 DOI: 10.1016/j.jbc.2024.107128] [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: 12/11/2023] [Revised: 02/21/2024] [Accepted: 02/23/2024] [Indexed: 03/05/2024] Open
Abstract
Both POLG and MGME1 are needed for mitochondrial DNA (mtDNA) maintenance in animal cells. POLG, the primary replicative polymerase of the mitochondria, has an exonuclease activity (3'→5') that corrects for the misincorporation of bases. MGME1 serves as an exonuclease (5'→3'), producing ligatable DNA ends. Although both have a critical role in mtDNA replication and elimination of linear fragments, these mechanisms are still not fully understood. Using digital PCR to evaluate and compare mtDNA integrity, we show that Mgme1 knock out (Mgme1 KK) tissue mtDNA is more fragmented than POLG exonuclease-deficient "Mutator" (Polg MM) or WT tissue. In addition, next generation sequencing of mutant hearts showed abundant duplications in/nearby the D-loop region and unique 100 bp duplications evenly spaced throughout the genome only in Mgme1 KK hearts. However, despite these unique mtDNA features at steady-state, we observed a similar delay in the degradation of mtDNA after an induced double strand DNA break in both Mgme1 KK and Polg MM models. Lastly, we characterized double mutant (Polg MM/Mgme1 KK) cells and show that mtDNA cannot be maintained without at least one of these enzymatic activities. We propose a model for the generation of these genomic abnormalities which suggests a role for MGME1 outside of nascent mtDNA end ligation. Our results highlight the role of MGME1 in and outside of the D-loop region during replication, support the involvement of MGME1 in dsDNA degradation, and demonstrate that POLG EXO and MGME1 can partially compensate for each other in maintaining mtDNA.
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Affiliation(s)
- Christian D Gonzalez
- MSTP and MCDB Programs, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Nadee Nissanka
- Department of Neurology, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Derek Van Booven
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Anthony J Griswold
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Carlos T Moraes
- Department of Neurology, University of Miami Miller School of Medicine, Miami, Florida, USA.
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25
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Borsche M, Dulovic-Mahlow M, Baumann H, Tunc S, Lüth T, Schaake S, Özcakir S, Westenberger A, Münchau A, Knappe E, Trinh J, Brüggemann N, Lohmann K. POLG2-Linked Mitochondrial Disease: Functional Insights from New Mutation Carriers and Review of the Literature. CEREBELLUM (LONDON, ENGLAND) 2024; 23:479-488. [PMID: 37085601 PMCID: PMC10951043 DOI: 10.1007/s12311-023-01557-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/05/2023] [Indexed: 04/23/2023]
Abstract
Different pathogenic variants in the DNA polymerase-gamma2 (POLG2) gene cause a rare, clinically heterogeneous mitochondrial disease. We detected a novel POLG2 variant (c.1270 T > C, p.Ser424Pro) in a family with adult-onset cerebellar ataxia and progressive ophthalmoplegia. We demonstrated altered mitochondrial integrity in patients' fibroblast cultures but no changes of the mitochondrial DNA were found when compared to controls. We consider this novel, segregating POLG2 variant as disease-causing in this family. Moreover, we systematically screened the literature for POLG2-linked phenotypes and re-evaluated all mutations published to date for pathogenicity according to current knowledge. Thereby, we identified twelve published, likely disease-causing variants in 19 patients only. The core features included progressive ophthalmoplegia and cerebellar ataxia; parkinsonism, neuropathy, cognitive decline, and seizures were also repeatedly found in adult-onset heterozygous POLG2-related disease. A severe phenotype relates to biallelic pathogenic variants in POLG2, i.e., newborn-onset liver failure, referred to as mitochondrial depletion syndrome. Our work underlines the broad clinical spectrum of POLG2-related disease and highlights the importance of functional characterization of variants of uncertain significance to enable meaningful genetic counseling.
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Affiliation(s)
- Max Borsche
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
- Department of Neurology, University of Lübeck and University Hospital Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | | | - Hauke Baumann
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Sinem Tunc
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
- Department of Neurology, University of Lübeck and University Hospital Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
- Institute of Systems Motor Science, University of Lübeck, Lübeck, Germany
| | - Theresa Lüth
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Susen Schaake
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Selin Özcakir
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Ana Westenberger
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Alexander Münchau
- Institute of Systems Motor Science, University of Lübeck, Lübeck, Germany
| | - Evelyn Knappe
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Joanne Trinh
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Norbert Brüggemann
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany.
- Department of Neurology, University of Lübeck and University Hospital Schleswig-Holstein, Campus Lübeck, Lübeck, Germany.
| | - Katja Lohmann
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
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Rathor L, Curry S, Park Y, McElroy T, Robles B, Sheng Y, Chen WW, Min K, Xiao R, Lee MH, Han SM. Mitochondrial stress in GABAergic neurons non-cell autonomously regulates organismal health and aging. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.20.585932. [PMID: 38585797 PMCID: PMC10996468 DOI: 10.1101/2024.03.20.585932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Mitochondrial stress within the nervous system can trigger non-cell autonomous responses in peripheral tissues. However, the specific neurons involved and their impact on organismal aging and health have remained incompletely understood. Here, we demonstrate that mitochondrial stress in γ-aminobutyric acid-producing (GABAergic) neurons in Caenorhabditis elegans ( C. elegans ) is sufficient to significantly alter organismal lifespan, stress tolerance, and reproductive capabilities. This mitochondrial stress also leads to significant changes in mitochondrial mass, energy production, and levels of reactive oxygen species (ROS). DAF-16/FoxO activity is enhanced by GABAergic neuronal mitochondrial stress and mediates the induction of these non-cell-autonomous effects. Moreover, our findings indicate that GABA signaling operates within the same pathway as mitochondrial stress in GABAergic neurons, resulting in non-cell-autonomous alterations in organismal stress tolerance and longevity. In summary, these data suggest the crucial role of GABAergic neurons in detecting mitochondrial stress and orchestrating non-cell-autonomous changes throughout the organism.
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27
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Kannan S, Gillespie SW, Picking WL, Picking WD, Lorson CL, Singh K. Inhibitors against DNA Polymerase I Family of Enzymes: Novel Targets and Opportunities. BIOLOGY 2024; 13:204. [PMID: 38666816 PMCID: PMC11048162 DOI: 10.3390/biology13040204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 03/18/2024] [Accepted: 03/20/2024] [Indexed: 04/28/2024]
Abstract
DNA polymerases replicate cellular genomes and/or participate in the maintenance of genome integrity. DNA polymerases sharing high sequence homology with E. coli DNA polymerase I (pol I) have been grouped in Family A. Pol I participates in Okazaki fragment maturation and in bacterial genome repair. Since its discovery in 1956, pol I has been extensively studied, primarily to gain deeper insights into the mechanism of DNA replication. As research on DNA polymerases advances, many novel functions of this group of polymerases are being uncovered. For example, human DNA polymerase θ (a Family A DNA pol) has been shown to synthesize DNA using RNA as a template, a function typically attributed to retroviral reverse transcriptase. Increased interest in drug discovery against pol θ has emerged due to its roles in cancer. Likewise, Pol I family enzymes also appear attractive as drug-development targets against microbial infections. Development of antimalarial compounds targeting apicoplast apPOL, an ortholog of Pol I, further extends the targeting of this family of enzymes. Here, we summarize reported drug-development efforts against Family A polymerases and future perspective regarding these enzymes as antibiotic targets. Recently developed techniques, such as artificial intelligence, can be used to facilitate the development of new drugs.
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Affiliation(s)
- Saathvik Kannan
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA; (S.K.); (S.W.G.); (W.L.P.); (W.D.P.); (C.L.L.)
| | - Samuel W. Gillespie
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA; (S.K.); (S.W.G.); (W.L.P.); (W.D.P.); (C.L.L.)
| | - Wendy L. Picking
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA; (S.K.); (S.W.G.); (W.L.P.); (W.D.P.); (C.L.L.)
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
| | - William D. Picking
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA; (S.K.); (S.W.G.); (W.L.P.); (W.D.P.); (C.L.L.)
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
| | - Christian L. Lorson
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA; (S.K.); (S.W.G.); (W.L.P.); (W.D.P.); (C.L.L.)
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
| | - Kamal Singh
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA; (S.K.); (S.W.G.); (W.L.P.); (W.D.P.); (C.L.L.)
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
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28
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Wilson GN, Tonk VS. Clinical-Genomic Analysis of 1261 Patients with Ehlers-Danlos Syndrome Outlines an Articulo-Autonomic Gene Network (Entome). Curr Issues Mol Biol 2024; 46:2620-2643. [PMID: 38534782 DOI: 10.3390/cimb46030166] [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: 01/01/2024] [Revised: 02/08/2024] [Accepted: 03/08/2024] [Indexed: 03/28/2024] Open
Abstract
Systematic evaluation of 80 history and 40 history findings diagnosed 1261 patients with Ehlers-Danlos syndrome (EDS) by direct or online interaction, and 60 key findings were selected for their relation to clinical mechanisms and/or management. Genomic testing results in 566 of these patients supported EDS relevance by their differences from those in 82 developmental disability patients and by their association with general rather than type-specific EDS findings. The 437 nuclear and 79 mitochondrial DNA changes included 71 impacting joint matrix (49 COL5), 39 bone (30 COL1/2/9/11), 22 vessel (12 COL3/8VWF), 43 vessel-heart (17FBN1/11TGFB/BR), 59 muscle (28 COL6/12), 56 neural (16 SCN9A/10A/11A), and 74 autonomic (13 POLG/25porphyria related). These genes were distributed over all chromosomes but the Y, a network analogized to an 'entome' where DNA change disrupts truncal mechanisms (skin constraint, neuromuscular support, joint vessel flexibility) and produces a mirroring cascade of articular and autonomic symptoms. The implied sequences of genes from nodal proteins to hypermobility to branching tissue laxity or dysautonomia symptoms would be ideal for large language/artificial intelligence analyses.
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Affiliation(s)
- Golder N Wilson
- Department of Pediatrics, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
- KinderGenome Genetics Private Practice, 5347 W Mockingbird, Dallas, TX 75209, USA
| | - Vijay S Tonk
- Director of Medical Genetics and the Cytogenomic Laboratory, Department of Pediatrics, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
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29
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Zuo RR, Jin M, Sun SZ. Etiological analysis of 167 cases of drug-resistant epilepsy in children. Ital J Pediatr 2024; 50:50. [PMID: 38481309 PMCID: PMC10938754 DOI: 10.1186/s13052-024-01619-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 02/24/2024] [Indexed: 03/17/2024] Open
Abstract
BACKGROUND To analyze the etiological distribution characteristics of drug-resistant epilepsy (DRE) in children, with the aim of providing valuable perspectives to enhance clinical practice. METHODS In this retrospective study, clinical data were collected on 167 children with DRE who were hospitalized between January 2020 and December 2022, including gender, age of onset, seizure types, video electroencephalogram(VEEG) recordings, neuroimaging, and genetic testing results. Based on the etiology of epilepsy, the enrolled children were categorized into different groups. The rank-sum test was conducted to compare the age of onset for different etiologies. RESULTS Of the 167 cases, 89 (53.3%) had a clear etiology. Among them, structural factors account for 23.4%, genetic factors for 19.2%, multiple factors for 7.2%, and immunological factors for 3.6%. The age of onset was significantly earlier in children with genetic causes than those with structural (P < 0.001) or immunological (P = 0.001) causes. CONCLUSIONS More than half of children with DRE have a distinct underlying cause, predominantly attributed to structural factors, followed by genetic factors. Genetic etiology primarily manifests at an early age, especially among children aged less than one year. This underscores the need for proactive enhancements in genetic testing to unveil the underlying causes and subsequently guide treatment protocols.
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Affiliation(s)
- Ran-Ran Zuo
- Department of Neurology, Hebei Childrens Hospital, 133, Jianhua South Street, 050000, Shijiazhuang, Hebei Province, China
| | - Mei Jin
- Department of Neurology, Hebei Childrens Hospital, 133, Jianhua South Street, 050000, Shijiazhuang, Hebei Province, China
- The Key Laboratory of Pediatric Epilepsy and Neurological Disorders of Hebei Province, 050000, Shijiazhuang, Hebei, China
| | - Su-Zhen Sun
- Department of Neurology, Hebei Childrens Hospital, 133, Jianhua South Street, 050000, Shijiazhuang, Hebei Province, China.
- The Key Laboratory of Pediatric Epilepsy and Neurological Disorders of Hebei Province, 050000, Shijiazhuang, Hebei, China.
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30
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Hu L, De Hoyos D, Lei Y, West AP, Walsh AJ. 3D convolutional neural networks predict cellular metabolic pathway use from fluorescence lifetime decay data. APL Bioeng 2024; 8:016112. [PMID: 38420625 PMCID: PMC10901549 DOI: 10.1063/5.0188476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 01/30/2024] [Indexed: 03/02/2024] Open
Abstract
Fluorescence lifetime imaging of the co-enzyme reduced nicotinamide adenine dinucleotide (NADH) offers a label-free approach for detecting cellular metabolic perturbations. However, the relationships between variations in NADH lifetime and metabolic pathway changes are complex, preventing robust interpretation of NADH lifetime data relative to metabolic phenotypes. Here, a three-dimensional convolutional neural network (3D CNN) trained at the cell level with 3D NAD(P)H lifetime decay images (two spatial dimensions and one time dimension) was developed to identify metabolic pathway usage by cancer cells. NADH fluorescence lifetime images of MCF7 breast cancer cells with three isolated metabolic pathways, glycolysis, oxidative phosphorylation, and glutaminolysis were obtained by a multiphoton fluorescence lifetime microscope and then segmented into individual cells as the input data for the classification models. The 3D CNN models achieved over 90% accuracy in identifying cancer cells reliant on glycolysis, oxidative phosphorylation, or glutaminolysis. Furthermore, the model trained with human breast cancer cell data successfully predicted the differences in metabolic phenotypes of macrophages from control and POLG-mutated mice. These results suggest that the integration of autofluorescence lifetime imaging with 3D CNNs enables intracellular spatial patterns of NADH intensity and temporal dynamics of the lifetime decay to discriminate multiple metabolic phenotypes. Furthermore, the use of 3D CNNs to identify metabolic phenotypes from NADH fluorescence lifetime decay images eliminates the need for time- and expertise-demanding exponential decay fitting procedures. In summary, metabolic-prediction CNNs will enable live-cell and in vivo metabolic measurements with single-cell resolution, filling a current gap in metabolic measurement technologies.
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Affiliation(s)
- Linghao Hu
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas 77843, USA
| | - Daniela De Hoyos
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas 77843, USA
| | - Yuanjiu Lei
- Department of Microbial Pathogenesis and Immunology, School of Medicine, Texas A&M University, Bryan, Texas 77807, USA
| | | | - Alex J. Walsh
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas 77843, USA
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31
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Lopergolo D, Rosini F, Pretegiani E, Bargagli A, Serchi V, Rufa A. Autosomal recessive cerebellar ataxias: a diagnostic classification approach according to ocular features. Front Integr Neurosci 2024; 17:1275794. [PMID: 38390227 PMCID: PMC10883068 DOI: 10.3389/fnint.2023.1275794] [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: 08/10/2023] [Accepted: 11/10/2023] [Indexed: 02/24/2024] Open
Abstract
Autosomal recessive cerebellar ataxias (ARCAs) are a heterogeneous group of neurodegenerative disorders affecting primarily the cerebellum and/or its afferent tracts, often accompanied by damage of other neurological or extra-neurological systems. Due to the overlap of clinical presentation among ARCAs and the variety of hereditary, acquired, and reversible etiologies that can determine cerebellar dysfunction, the differential diagnosis is challenging, but also urgent considering the ongoing development of promising target therapies. The examination of afferent and efferent visual system may provide neurophysiological and structural information related to cerebellar dysfunction and neurodegeneration thus allowing a possible diagnostic classification approach according to ocular features. While optic coherence tomography (OCT) is applied for the parametrization of the optic nerve and macular area, the eye movements analysis relies on a wide range of eye-tracker devices and the application of machine-learning techniques. We discuss the results of clinical and eye-tracking oculomotor examination, the OCT findings and some advancing of computer science in ARCAs thus providing evidence sustaining the identification of robust eye parameters as possible markers of ARCAs.
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Affiliation(s)
- Diego Lopergolo
- Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
- UOC Neurologia e Malattie Neurometaboliche, Azienda Ospedaliero-Universitaria Senese, Siena, Italy
| | - Francesca Rosini
- UOC Stroke Unit, Department of Emergenza-Urgenza, Azienda Ospedaliero-Universitaria Senese, Siena, Italy
| | - Elena Pretegiani
- Unit of Neurology, Centre Hospitalier Universitaire Vaudoise Lausanne, Unit of Neurology and Cognitive Neurorehabilitation, Universitary Hospital of Fribourg, Fribourg, Switzerland
| | - Alessia Bargagli
- Evalab-Neurosense, Department of Medicine Surgery and Neuroscience, University of Siena, Siena, Italy
| | - Valeria Serchi
- Evalab-Neurosense, Department of Medicine Surgery and Neuroscience, University of Siena, Siena, Italy
| | - Alessandra Rufa
- Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
- UOC Neurologia e Malattie Neurometaboliche, Azienda Ospedaliero-Universitaria Senese, Siena, Italy
- Evalab-Neurosense, Department of Medicine Surgery and Neuroscience, University of Siena, Siena, Italy
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32
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Hu YWE. Low Complex I and III Activity-Derived Myopathy Causing Recurrent Exertional Rhabdomyolysis. Curr Sports Med Rep 2024; 23:41-44. [PMID: 38315431 DOI: 10.1249/jsr.0000000000001138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Affiliation(s)
- Yao-Wen Eliot Hu
- Department of Family and Community Medicine, Uniformed Services University of Health Sciences, Bethesda, MD
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33
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Kadohisa M, Okamoto T, Yamamoto M, Uebayashi EY, Sonoda M, Ogawa E, Yokoyama A, Kawasaki H, Hiejima E, Ito S, Togawa T, Imagawa K, Murayama K, Okajima H, Hatano E. Living donor liver transplantation for myocerebrohepatopathy spectrum due to POLG mutations. Pediatr Transplant 2024; 28:e14659. [PMID: 38012111 DOI: 10.1111/petr.14659] [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: 06/06/2023] [Revised: 09/26/2023] [Accepted: 11/15/2023] [Indexed: 11/29/2023]
Abstract
BACKGROUND POLG is one of several nuclear genes associated with mitochondrial DNA maintenance defects and is a group of diseases caused by mitochondrial DNA deficiency that results in impaired adenosine triphosphate production and organ dysfunction. Myocerebrohepatopathy spectrum (MCHS) is the most severe and earliest presentation of POLG mutations, and liver transplantation (LT) for MCHS has never been reported. CASE PRESENTATION The patient was a 3-month-old boy with acute liver failure and no neurological manifestations (e.g., seizures). We performed a living donor LT using a left lateral segment graft from his father. The postoperative course was uneventful. Subsequently, a homozygous POLG mutation (c.2890C>T, p. R964C) was identified by multigene analysis of neonatal/infantile intrahepatic cholestasis. Moreover, respiratory chain complex I, II, and III enzyme activities and the ratio of mtDNA to nuclear DNA in the liver were reduced. Therefore, we considered that these clinical manifestations and examination findings met the definition for MCHS. During meticulous follow-up, the patient had shown satisfactory physical growth and mental development until the time of writing this report. CONCLUSION We presumed that the absence of remarkable neurologic manifestations prior to LT in patients with MCHS is a good indication for LT and contributes to a better prognosis in the present case.
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Affiliation(s)
- Masashi Kadohisa
- Department of Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Pediatric Surgery, Kyoto University Hospital, Kyoto, Japan
| | - Tatsuya Okamoto
- Department of Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Pediatric Surgery, Kyoto University Hospital, Kyoto, Japan
| | - Miki Yamamoto
- Department of Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Pediatric Surgery, Kyoto University Hospital, Kyoto, Japan
| | - Elena Yukie Uebayashi
- Department of Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Pediatric Surgery, Kyoto University Hospital, Kyoto, Japan
| | - Mari Sonoda
- Department of Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Pediatric Surgery, Kyoto University Hospital, Kyoto, Japan
| | - Eri Ogawa
- Department of Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Pediatric Surgery, Kyoto University Hospital, Kyoto, Japan
| | - Atsushi Yokoyama
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Hidenori Kawasaki
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Eitaro Hiejima
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Shogo Ito
- Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Takao Togawa
- Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Kazuo Imagawa
- Department of Child Health, Institute of Medicine, University of Tsukuba, Ibaraki, Japan
| | - Kei Murayama
- Department of Metabolism, Center for Medical Genetics, Chiba Children's Hospital, Chiba, Japan
| | - Hideaki Okajima
- Department of Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Pediatric Surgery, Kanazawa Medical University, Kanazawa, Japan
| | - Etsuro Hatano
- Department of Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Pediatric Surgery, Kyoto University Hospital, Kyoto, Japan
- Department of Hepato-Biliary-Pancreatic Surgery and Transplantation, Kyoto University Hospital, Kyoto, Japan
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34
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Reitinger JC, Mackay DD. Optic Neuropathy Associated with POLG Mutations: A Case Series and Literature Review. J Neuroophthalmol 2024:00041327-990000000-00567. [PMID: 38294884 DOI: 10.1097/wno.0000000000002089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2024]
Abstract
BACKGROUND The clinical characteristics of patients with polymerase gamma (POLG) mutation-associated optic neuropathy remain incompletely characterized. METHODS We describe the clinical characteristics of 3 patients with POLG-associated optic neuropathy. We performed a literature review of optic neuropathy cases associated with POLG mutations and compared them with our cohort. RESULTS Many published cases of POLG-associated optic neuropathy in our literature review lacked details regarding severity of vision loss, visual field defects, and optical coherence tomography analysis. The clinical presentation of POLG mutations remains widely variable in age (from pediatric cases to adults) and associated systemic findings. All patients in our literature review presented with systemic symptoms, most commonly muscle weakness, ptosis, and ophthalmoplegia, whereas many young patients had severe systemic symptoms. In our case series, all 3 cases had isolated optic neuropathy affecting the papillomacular bundle, with signs such as reduced visual acuity and color vision, central visual field defects, temporal retinal nerve fiber layer loss with temporal optic disc pallor, and retinal ganglion cell complex loss. In addition, 2 of the 3 cases had added mitochondrial stressors in addition to the POLG mutation. CONCLUSIONS Clinicians should be aware that POLG mutations can present as isolated optic neuropathy primarily affecting the papillomacular bundle. With mitochondrial failure being the likely underlying pathogenic mechanism in POLG-associated optic neuropathy, helping affected patients eliminate mitochondrial stressors may be important in reducing the risk for progressive vision loss in this otherwise currently untreatable disorder.
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Affiliation(s)
- Jeremy C Reitinger
- Department of Ophthalmology (JCR), Indiana University School of Medicine, Indianapolis, Indiana; and Departments of Neurology (DDM), Ophthalmology, and Neurosurgery, Indiana University School of Medicine, Indianapolis, Indiana
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Fan P, Wang H, Zhao F, Zhang T, Li J, Sun X, Yu Y, Xiong H, Lai L, Sui T. Targeted mutagenesis in mice via an engineered AsCas12f1 system. Cell Mol Life Sci 2024; 81:63. [PMID: 38280977 PMCID: PMC10821844 DOI: 10.1007/s00018-023-05100-3] [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: 10/19/2023] [Revised: 12/17/2023] [Accepted: 12/20/2023] [Indexed: 01/29/2024]
Abstract
SpCas9 and AsCas12a are widely utilized as genome editing tools in human cells, but their applications are largely limited by their bulky size. Recently, AsCas12f1 protein, with a small size (422 amino acids), has been demonstrated to be capable of cleaving double-stranded DNA protospacer adjacent motif (PAM). However, low editing efficiency and large differences in activity against different genomic loci have been a limitation in its application. Here, we show that engineered AsCas12f1 sgRNA has significantly improved the editing efficiency in human cells and mouse embryos. Moreover, we successfully generated three stable mouse mutant disease models using the engineered CRISPR-AsCas12f1 system in this study. Collectively, our work uncovers the engineered AsCas12f1 system expands mini CRISPR toolbox, providing a remarkable promise for therapeutic applications.
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Affiliation(s)
- Peng Fan
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Hejun Wang
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Feiyu Zhao
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Tao Zhang
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Jinze Li
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Xiaodi Sun
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Yongduo Yu
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Haoyang Xiong
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Liangxue Lai
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, 130062, China.
- Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, Guangdong, China.
| | - Tingting Sui
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, 130062, China.
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Ali A, Esmaeil A, Behbehani R. Mitochondrial Chronic Progressive External Ophthalmoplegia. Brain Sci 2024; 14:135. [PMID: 38391710 PMCID: PMC10887352 DOI: 10.3390/brainsci14020135] [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: 12/25/2023] [Revised: 01/22/2024] [Accepted: 01/26/2024] [Indexed: 02/24/2024] Open
Abstract
BACKGROUND Chronic progressive external ophthalmoplegia (CPEO) is a rare disorder that can be at the forefront of several mitochondrial diseases. This review overviews mitochondrial CPEO encephalomyopathies to enhance accurate recognition and diagnosis for proper management. METHODS This study is conducted based on publications and guidelines obtained by selective review in PubMed. Randomized, double-blind, placebo-controlled trials, Cochrane reviews, and literature meta-analyses were particularly sought. DISCUSSION CPEO is a common presentation of mitochondrial encephalomyopathies, which can result from alterations in mitochondrial or nuclear DNA. Genetic sequencing is the gold standard for diagnosing mitochondrial encephalomyopathies, preceded by non-invasive tests such as fibroblast growth factor-21 and growth differentiation factor-15. More invasive options include a muscle biopsy, which can be carried out after uncertain diagnostic testing. No definitive treatment option is available for mitochondrial diseases, and management is mainly focused on lifestyle risk modification and supplementation to reduce mitochondrial load and symptomatic relief, such as ptosis repair in the case of CPEO. Nevertheless, various clinical trials and endeavors are still at large for achieving beneficial therapeutic outcomes for mitochondrial encephalomyopathies. KEY MESSAGES Understanding the varying presentations and genetic aspects of mitochondrial CPEO is crucial for accurate diagnosis and management.
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Affiliation(s)
- Ali Ali
- Neuro-Ophthalmology Unit, Ibn Sina Hospital, Al-Bahar Ophthalmology Center, Kuwait City 70035, Kuwait
| | - Ali Esmaeil
- Neuro-Ophthalmology Unit, Ibn Sina Hospital, Al-Bahar Ophthalmology Center, Kuwait City 70035, Kuwait
| | - Raed Behbehani
- Neuro-Ophthalmology Unit, Ibn Sina Hospital, Al-Bahar Ophthalmology Center, Kuwait City 70035, Kuwait
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Basilisco G, Marchi M, Coletta M. Chronic intestinal pseudo-obstruction in adults: A practical guide to identify patient subgroups that are suitable for more specific treatments. Neurogastroenterol Motil 2024; 36:e14715. [PMID: 37994282 DOI: 10.1111/nmo.14715] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 11/06/2023] [Accepted: 11/10/2023] [Indexed: 11/24/2023]
Abstract
Chronic intestinal pseudo-obstruction is a rare and heterogeneous syndrome characterized by recurrent symptoms of intestinal obstruction with radiological features of dilated small or large intestine with air/fluid levels in the absence of any mechanical occlusive lesion. Several diseases may be associated with chronic intestinal pseudo-obstruction and in these cases, the prognosis and treatment are related to the underlying disease. Also, in its "primary or idiopathic" form, two subgroups of patients should be determined as they require a more specific therapeutic approach: patients whose chronic intestinal pseudo-obstruction is due to sporadic autoimmune/inflammatory mechanisms and patients whose neuromuscular changes are genetically determined. In a context of a widely heterogeneous adult population presenting chronic intestinal pseudo-obstruction, this review aims to summarize a practical diagnostic workup for identifying definite subgroups of patients who might benefit from more specific treatments, based on the etiology of their underlying condition.
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Affiliation(s)
- Guido Basilisco
- Gastroenterology and Endoscopic Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Margherita Marchi
- Neuroalgology Unit, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milan, Italy
| | - Marina Coletta
- Gastroenterology and Endoscopic Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
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Alves CAPF, Whitehead MT. Advancing the neuroimaging diagnosis and understanding of mitochondrial disorders. Neurotherapeutics 2024; 21:e00324. [PMID: 38306952 PMCID: PMC10903090 DOI: 10.1016/j.neurot.2024.e00324] [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: 11/03/2023] [Revised: 01/16/2024] [Accepted: 01/16/2024] [Indexed: 02/04/2024] Open
Abstract
Mitochondrial diseases, a diverse and intricate group of disorders, result from both nuclear DNA and mitochondrial DNA malfunctions, leading to a decrease in cellular energy (ATP) production. The increasing understanding of molecular, biochemical, and genetic irregularities associated with mitochondrial dysfunction has led to a wider recognition of varying mitochondrial disease phenotypes. This broadening landscape has led to a diverse array of neuroimaging findings, posing a challenge to radiologists in identifying the extensive range of possible patterns. This review meticulously describes the central imaging features of mitochondrial diseases in children, as revealed by neuroimaging. It spans from traditional imaging findings to more recent and intricate diagnoses, offering insights and highlighting advancements in neuroimaging technology that can potentially guide a more efficient and accurate diagnostic approach.
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Affiliation(s)
- César Augusto P F Alves
- Division of Neuroradiology, Department of Radiology, Boston Children's Hospital - BCH Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, United States.
| | - Matthew T Whitehead
- Division of Neuroradiology, Department of Radiology, The Children's Hospital of Philadelphia, PA, United States; Perelman School of Medicine, University of Pennsylvania Perelman School of Medicine of Philadelphia, United States.
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Huang PY, Shih IA, Liao YC, You HL, Lee MJ. FT895 Impairs Mitochondrial Function in Malignant Peripheral Nerve Sheath Tumor Cells. Int J Mol Sci 2023; 25:277. [PMID: 38203448 PMCID: PMC10779378 DOI: 10.3390/ijms25010277] [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: 11/20/2023] [Revised: 12/19/2023] [Accepted: 12/21/2023] [Indexed: 01/12/2024] Open
Abstract
Neurofibromatosis type 1 (NF1) stands as a prevalent neurocutaneous disorder. Approximately a quarter of NF1 patients experience the development of plexiform neurofibromas, potentially progressing into malignant peripheral nerve sheath tumors (MPNST). FT895, an HDAC11 inhibitor, exhibits potent anti-tumor effects on MPNST cells and enhances the cytotoxicity of cordycepin against MPNST. The study aims to investigate the molecular mechanism underlying FT895's efficacy against MPNST cells. Initially, our study unveiled that FT895 disrupts mitochondrial biogenesis and function. Post-FT895 treatment, reactive oxygen species (ROS) in MPNST notably increased, while mitochondrial DNA copy numbers decreased significantly. Seahorse analysis indicated a considerable decrease in basal, maximal, and ATP-production-coupled respiration following FT895 treatment. Immunostaining highlighted FT895's role in promoting mitochondrial aggregation without triggering mitophagy, possibly due to reduced levels of XBP1, Parkin, and PINK1 proteins. Moreover, the study using CHIP-qPCR analysis revealed a significant reduction in the copy numbers of promoters of the MPV17L2, POLG, TFAM, PINK1, and Parkin genes. The RNA-seq analysis underscored the prominent role of the HIF-1α signaling pathway post-FT895 treatment, aligning with the observed impairment in mitochondrial respiration. In summary, the study pioneers the revelation that FT895 induces mitochondrial respiratory damage in MPNST cells.
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Affiliation(s)
- Po-Yuan Huang
- Department of Neurology, National Taiwan University Hospital, No. 7, Chung-Shan South Road, Taipei 10012, Taiwan; (P.-Y.H.); (I.-A.S.); (Y.-C.L.); (H.-L.Y.)
| | - I-An Shih
- Department of Neurology, National Taiwan University Hospital, No. 7, Chung-Shan South Road, Taipei 10012, Taiwan; (P.-Y.H.); (I.-A.S.); (Y.-C.L.); (H.-L.Y.)
| | - Ying-Chih Liao
- Department of Neurology, National Taiwan University Hospital, No. 7, Chung-Shan South Road, Taipei 10012, Taiwan; (P.-Y.H.); (I.-A.S.); (Y.-C.L.); (H.-L.Y.)
| | - Huey-Ling You
- Department of Neurology, National Taiwan University Hospital, No. 7, Chung-Shan South Road, Taipei 10012, Taiwan; (P.-Y.H.); (I.-A.S.); (Y.-C.L.); (H.-L.Y.)
| | - Ming-Jen Lee
- Department of Neurology, National Taiwan University Hospital, No. 7, Chung-Shan South Road, Taipei 10012, Taiwan; (P.-Y.H.); (I.-A.S.); (Y.-C.L.); (H.-L.Y.)
- Department of Medical Genetics, National Taiwan University Hospital, Taipei 10012, Taiwan
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Shestakova ED, Tumbinsky RS, Andreev DE, Rozov FN, Shatsky IN, Terenin IM. The Roles of eIF4G2 in Leaky Scanning and Reinitiation on the Human Dual-Coding POLG mRNA. Int J Mol Sci 2023; 24:17149. [PMID: 38138978 PMCID: PMC10742948 DOI: 10.3390/ijms242417149] [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: 11/03/2023] [Revised: 11/29/2023] [Accepted: 12/01/2023] [Indexed: 12/24/2023] Open
Abstract
Upstream open reading frames (uORFs) are a frequent feature of eukaryotic mRNAs. Upstream ORFs govern main ORF translation in a variety of ways, but, in a nutshell, they either filter out scanning ribosomes or allow downstream translation initiation via leaky scanning or reinitiation. Previous reports concurred that eIF4G2, a long-known but insufficiently studied eIF4G1 homologue, can rescue the downstream translation, but disagreed on whether it is leaky scanning or reinitiation that eIF4G2 promotes. Here, we investigated a unique human mRNA that encodes two highly conserved proteins (POLGARF with unknown function and POLG, the catalytic subunit of the mitochondrial DNA polymerase) in overlapping reading frames downstream of a regulatory uORF. We show that the uORF renders the translation of both POLGARF and POLG mRNAs reliant on eIF4G2. Mechanistically, eIF4G2 enhances both leaky scanning and reinitiation, and it appears that ribosomes can acquire eIF4G2 during the early steps of reinitiation. This emphasizes the role of eIF4G2 as a multifunctional scanning guardian that replaces eIF4G1 to facilitate ribosome movement but not ribosome attachment to an mRNA.
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Affiliation(s)
- Ekaterina D. Shestakova
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119234 Moscow, Russia (R.S.T.)
| | - Roman S. Tumbinsky
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119234 Moscow, Russia (R.S.T.)
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia (I.N.S.)
| | - Dmitri E. Andreev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia (I.N.S.)
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, RAS, 117997 Moscow, Russia
| | - Fedor N. Rozov
- Department of Biochemistry, School of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Ivan N. Shatsky
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia (I.N.S.)
| | - Ilya M. Terenin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia (I.N.S.)
- Translational Medicine Research Center, Sirius University of Science and Technology, Olimpiyskiy ave. b.1, 354349 Sochi, Russia
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Sturgis J, Singh R, Caron Q, Samuels IS, Shiju TM, Mukkara A, Freedman P, Bonilha VL. Modeling aging and retinal degeneration with mitochondrial DNA mutation burden. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.30.569464. [PMID: 38076962 PMCID: PMC10705408 DOI: 10.1101/2023.11.30.569464] [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] [Indexed: 12/17/2023]
Abstract
Somatic mitochondrial DNA (mtDNA) mutation accumulation has been observed in individuals with retinal degenerative disorders. To study the effects of aging and mtDNA mutation accumulation in the retina, a Polymerase gamma (POLG) deficiency model, the POLGD257A mutator mice (PolgD257A), was used. POLG is an enzyme responsible for regulating mtDNA replication and repair. Retinas of young and older mice with this mutation were analyzed in vivo and ex vivo to provide new insights into the contribution of age-related mitochondrial dysfunction due to mtDNA damage. Optical coherence tomography (OCT) image analysis revealed a decrease in retinal and photoreceptor thickness starting at 6 months of age in mice with the POLGD257A mutation compared to wild-type (WT) mice. Electroretinography (ERG) testing showed a significant decrease in all recorded responses at 6 months of age. Sections labeled with markers of different types of retinal cells, including cones, rods, and bipolar cells, exhibited decreased labeling starting at 6 months. However, electron microscopy analysis revealed differences in retinal pigment epithelium (RPE) mitochondria morphology beginning at 3 months. Interestingly, there was no increase in oxidative stress observed in the retina or RPE of POLGD257A mice. Additionally, POLGD257A RPE exhibited an accelerated rate of autofluorescence cytoplasmic granule formation and accumulation. Mitochondrial markers displayed decreased abundance in protein lysates obtained from retina and RPE samples. These findings suggest that the accumulation of mitochondrial DNA mutations leads to impaired mitochondrial function and accelerated aging, resulting in retinal degeneration.
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Affiliation(s)
- John Sturgis
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Rupesh Singh
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Quinn Caron
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Ivy S. Samuels
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA
- Research Service, Louis Stokes Cleveland VA Medical Center, Cleveland, OH
| | - Thomas Micheal Shiju
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Aditi Mukkara
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA
- College of Arts and Sciences, Case Western Reserve University, Cleveland, OH, USA
| | - Paul Freedman
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA
- Debusk College of Osteopathic Medicine, Knoxville, TN, USA
| | - Vera L. Bonilha
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
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Gilea AI, Magistrati M, Notaroberto I, Tiso N, Dallabona C, Baruffini E. The Saccharomyces cerevisiae mitochondrial DNA polymerase and its contribution to the knowledge about human POLG-related disorders. IUBMB Life 2023; 75:983-1002. [PMID: 37470284 DOI: 10.1002/iub.2770] [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: 05/31/2023] [Accepted: 07/05/2023] [Indexed: 07/21/2023]
Abstract
Most eukaryotes possess a mitochondrial genome, called mtDNA. In animals and fungi, the replication of mtDNA is entrusted by the DNA polymerase γ, or Pol γ. The yeast Pol γ is composed only of a catalytic subunit encoded by MIP1. In humans, Pol γ is a heterotrimer composed of a catalytic subunit homolog to Mip1, encoded by POLG, and two accessory subunits. In the last 25 years, more than 300 pathological mutations in POLG have been identified as the cause of several mitochondrial diseases, called POLG-related disorders, which are characterized by multiple mtDNA deletions and/or depletion in affected tissues. In this review, at first, we summarize the biochemical properties of yeast Mip1, and how mutations, especially those introduced recently in the N-terminal and C-terminal regions of the enzyme, affect the in vitro activity of the enzyme and the in vivo phenotype connected to the mtDNA stability and to the mtDNA extended and point mutability. Then, we focus on the use of yeast harboring Mip1 mutations equivalent to the human ones to confirm their pathogenicity, identify the phenotypic defects caused by these mutations, and find both mechanisms and molecular compounds able to rescue the detrimental phenotype. A closing chapter will be dedicated to other polymerases found in yeast mitochondria, namely Pol ζ, Rev1 and Pol η, and to their genetic interactions with Mip1 necessary to maintain mtDNA stability and to avoid the accumulation of spontaneous or induced point mutations.
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Affiliation(s)
- Alexandru Ionut Gilea
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Martina Magistrati
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Ilenia Notaroberto
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Natascia Tiso
- Department of Biology, University of Padova, Padova, Italy
| | - Cristina Dallabona
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Enrico Baruffini
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
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Liu H, Gao M, Sun Q, Chen S, Luo Y, Yang H, Li Q, Li J, Yang G. A case of mitochondrial myopathy and chronic progressive external ophthalmoplegia. ZHONG NAN DA XUE XUE BAO. YI XUE BAN = JOURNAL OF CENTRAL SOUTH UNIVERSITY. MEDICAL SCIENCES 2023; 48:1760-1768. [PMID: 38432868 PMCID: PMC10929950 DOI: 10.11817/j.issn.1672-7347.2023.220605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Indexed: 03/05/2024]
Abstract
Mitochondrial myopathy is a group of multi-system diseases in which mitochondrial DNA (mtDNA) or nuclear DNA (nDNA) defects lead to structural and functional dysfunction of mitochondria. The clinical manifestations of mitochondrial myopathy are complex and varied, and the testing for mtDNA and nDNA is not widely available, so misdiagnosis or missed diagnosis is common. Chronic progressive external ophthalmoplegia (CPEO) is a common type of mitochondrial myopathy, which is characterized by blepharoptosis. Here we report a 38-year-old female with mitochondrial myopathy presented with chronic numbness and weakness of the limbs, accompanied by blepharoptosis that was recently noticed. Laboratory and head magnetic resonance imaging (MRI) examinations showed no obvious abnormalities. Muscle and nerve biopsies showed characteristic ragged red fibers (RRFs) and large aggregates of denatured mitochondria. Testing for mtDNA and nDNA showed a known mutation c.2857C>T (p.R953C) and a novel variant c.2391G>C (p.M797I) in the polymerase gamma (POLG)gene, so the patient was diagnosed as mitochondrial myopathy. Clinicians should pay more attention to long-term unexplained skeletal muscle diseases with recent onset blepharoptosis. Histopathologic examination and genetic testing are of great value in the early diagnosis and therapeutic intervention.
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Affiliation(s)
- Haokun Liu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008.
| | - Ming Gao
- Department of Geriatrics, Xiangya Hospital, Central South University, Changsha 410008
| | - Qiying Sun
- Department of Geriatrics, Xiangya Hospital, Central South University, Changsha 410008
| | - Si Chen
- Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008
| | - Yuebei Luo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008
| | - Huan Yang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008
| | - Qiuxiang Li
- Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008
| | - Jing Li
- Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008
| | - Guang Yang
- Department of General Medicine, Xiangya Hospital, Central South University, Changsha 410008, China.
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Nusir A, Sinclair P, Kabbani N. Mitochondrial Proteomes in Neural Cells: A Systematic Review. Biomolecules 2023; 13:1638. [PMID: 38002320 PMCID: PMC10669788 DOI: 10.3390/biom13111638] [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: 10/10/2023] [Revised: 11/07/2023] [Accepted: 11/09/2023] [Indexed: 11/26/2023] Open
Abstract
Mitochondria are ancient endosymbiotic double membrane organelles that support a wide range of eukaryotic cell functions through energy, metabolism, and cellular control. There are over 1000 known proteins that either reside within the mitochondria or are transiently associated with it. These mitochondrial proteins represent a functional subcellular protein network (mtProteome) that is encoded by mitochondrial and nuclear genomes and significantly varies between cell types and conditions. In neurons, the high metabolic demand and differential energy requirements at the synapses are met by specific modifications to the mtProteome, resulting in alterations in the expression and functional properties of the proteins involved in energy production and quality control, including fission and fusion. The composition of mtProteomes also impacts the localization of mitochondria in axons and dendrites with a growing number of neurodegenerative diseases associated with changes in mitochondrial proteins. This review summarizes the findings on the composition and properties of mtProteomes important for mitochondrial energy production, calcium and lipid signaling, and quality control in neural cells. We highlight strategies in mass spectrometry (MS) proteomic analysis of mtProteomes from cultured cells and tissue. The research into mtProteome composition and function provides opportunities in biomarker discovery and drug development for the treatment of metabolic and neurodegenerative disease.
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Affiliation(s)
- Aya Nusir
- Interdisciplinary Program in Neuroscience, School of Systems Biology, George Mason University, Fairfax, VA 22030, USA;
| | - Patricia Sinclair
- School of Systems Biology, George Mason University, Fairfax, VA 22030, USA;
| | - Nadine Kabbani
- Interdisciplinary Program in Neuroscience, School of Systems Biology, George Mason University, Fairfax, VA 22030, USA;
- School of Systems Biology, George Mason University, Fairfax, VA 22030, USA;
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Henrich MT, Oertel WH, Surmeier DJ, Geibl FF. Mitochondrial dysfunction in Parkinson's disease - a key disease hallmark with therapeutic potential. Mol Neurodegener 2023; 18:83. [PMID: 37951933 PMCID: PMC10640762 DOI: 10.1186/s13024-023-00676-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 10/30/2023] [Indexed: 11/14/2023] Open
Abstract
Mitochondrial dysfunction is strongly implicated in the etiology of idiopathic and genetic Parkinson's disease (PD). However, strategies aimed at ameliorating mitochondrial dysfunction, including antioxidants, antidiabetic drugs, and iron chelators, have failed in disease-modification clinical trials. In this review, we summarize the cellular determinants of mitochondrial dysfunction, including impairment of electron transport chain complex 1, increased oxidative stress, disturbed mitochondrial quality control mechanisms, and cellular bioenergetic deficiency. In addition, we outline mitochondrial pathways to neurodegeneration in the current context of PD pathogenesis, and review past and current treatment strategies in an attempt to better understand why translational efforts thus far have been unsuccessful.
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Affiliation(s)
- Martin T Henrich
- Department of Psychiatry and Psychotherapy, Philipps University Marburg, 35039, Marburg, Germany
- Department of Neurology, Philipps University Marburg, 35043, Marburg, Germany
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Wolfgang H Oertel
- Department of Neurology, Philipps University Marburg, 35043, Marburg, Germany
| | - D James Surmeier
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Fanni F Geibl
- Department of Psychiatry and Psychotherapy, Philipps University Marburg, 35039, Marburg, Germany.
- Department of Neurology, Philipps University Marburg, 35043, Marburg, Germany.
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA.
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46
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Manning A, Han V, Stephens A, Wang R, Bush N, Bard M, Ramirez JM, Kalume F. Elevated susceptibility to exogenous seizure triggers and impaired interneuron excitability in a mouse model of Leigh syndrome epilepsy. Neurobiol Dis 2023; 187:106288. [PMID: 37704057 PMCID: PMC10621616 DOI: 10.1016/j.nbd.2023.106288] [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: 05/28/2023] [Revised: 08/12/2023] [Accepted: 09/10/2023] [Indexed: 09/15/2023] Open
Abstract
Mutations in the NADH dehydrogenase (ubiquinone reductase) iron‑sulfur protein 4 (NDUFS4) gene, which encodes for a key structural subunit of the OXFOS complex I (CI), lead to the most common form of mitochondrial disease in children known as Leigh syndrome (LS). As in other mitochondrial diseases, epileptic seizures constitute one of the most significant clinical features of LS. These seizures are often very difficult to treat and are a sign of poor disease prognosis. Mice with whole-body Ndufs4 KO are a well-validated model of LS; they exhibit epilepsy and several other clinical features of LS. We have previously shown that mice with Ndufs4 KO in only GABAergic interneurons (Gad2-Ndufs4-KO) reproduce the severe epilepsy phenotype observed in the global KO mice. This observation indicated that these mice represent an excellent model of LS epilepsy isolated from other clinical manifestations of the disease. To further characterize this epilepsy phenotype, we investigated seizure susceptibility to selected exogenous seizure triggers in Gad2-Ndufs4-KO mice. Then, using electrophysiology, imaging, and immunohistochemistry, we studied the cellular, physiological, and neuroanatomical consequences of Ndufs4 KO in GABAergic interneurons. Homozygous KO of Ndufs4 in GABAergic interneurons leads to a prominent susceptibility to exogenous seizure triggers, impaired interneuron excitability and interneuron loss. Finally, we found that the hippocampus and cortex participate in the generation of seizure activity in Gad2-Ndufs4-KO mice. These findings further define the LS epilepsy phenotype and provide important insights into the cellular mechanisms underlying epilepsy in LS and other mitochondrial diseases.
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Affiliation(s)
- Arena Manning
- Graduate Program in Neuroscience, University of Washington, Seattle, WA, United States of America; Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States of America
| | - Victor Han
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States of America
| | - Alexa Stephens
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States of America
| | - Rose Wang
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States of America
| | - Nicholas Bush
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States of America
| | - Michelle Bard
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States of America
| | - Jan M Ramirez
- Graduate Program in Neuroscience, University of Washington, Seattle, WA, United States of America; Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States of America; Department of Neurological Surgery, University of Washington, Seattle, WA, United States of America
| | - Franck Kalume
- Graduate Program in Neuroscience, University of Washington, Seattle, WA, United States of America; Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States of America; Department of Neurological Surgery, University of Washington, Seattle, WA, United States of America.
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47
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Aloisio S, Satolli S, Bellini G, Lopriore P. Parkinsonism in complex neurogenetic disorders: lessons from hereditary dementias, adult-onset ataxias and spastic paraplegias. Neurol Sci 2023; 44:3379-3388. [PMID: 37648940 PMCID: PMC10495519 DOI: 10.1007/s10072-023-07044-9] [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: 08/02/2023] [Accepted: 08/22/2023] [Indexed: 09/01/2023]
Abstract
Parkinsonism is a syndrome characterized by bradykinesia in combination with either rest tremor, rigidity, or both. These features are the cardinal manifestations of Parkinson's disease, the most common cause of parkinsonism, and atypical parkinsonian disorders. However, parkinsonism can be a manifestation of complex neurological and neurodegenerative genetically determined disorders, which have a vast and heterogeneous motor and non-motor phenotypic features. Hereditary dementias, adult-onset ataxias and spastic paraplegias represent only few of this vast group of neurogenetic diseases. This review will provide an overview of parkinsonism's clinical features within adult-onset neurogenetic diseases which a neurologist could face with. Understanding parkinsonism and its characteristics in the context of the aforementioned neurological conditions may provide insights into pathophysiological mechanisms and have important clinical implications, including diagnostic and therapeutic aspects.
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Affiliation(s)
- Simone Aloisio
- Department of Advanced Medical and Surgical Sciences (DAMSS), University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Sara Satolli
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Gabriele Bellini
- Department of Clinical and Experimental Medicine, Neurological Institute, University of Pisa, Pisa, Italy
| | - Piervito Lopriore
- Department of Clinical and Experimental Medicine, Neurological Institute, University of Pisa, Pisa, Italy.
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Bayazit MB, Francois A, McGrail E, Accornero F, Stratton MS. mt-tRNAs in the polymerase gamma mutant heart. THE JOURNAL OF CARDIOVASCULAR AGING 2023; 3:41. [PMID: 38235059 PMCID: PMC10793997 DOI: 10.20517/jca.2023.26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Introduction Mice harboring a D257A mutation in the proofreading domain of the mitochondrial DNA polymerase, Polymerase Gamma (POLG), experience severe metabolic dysfunction and display hallmarks of accelerated aging. We previously reported a mitochondrial unfolded protein response (UPTmt) - like (UPRmt-like) gene and protein expression pattern in the right ventricular tissue of POLG mutant mice. Aim We sought to determine if POLG mutation altered the expression of genes encoded by the mitochondria in a way that might also reduce proteotoxic stress. Methods and Results The expression of genes encoded by the mitochondrial DNA was interrogated via RNA-seq and northern blot analysis. A striking, location-dependent effect was seen in the expression of mitochondrial-encoded tRNAs in the POLG mutant as assayed by RNA-seq. These expression changes were negatively correlated with the tRNA partner amino acid's amyloidogenic potential. Direct measurement by northern blot was conducted on candidate mt-tRNAs identified from the RNA-seq. This analysis confirmed reduced expression of MT-TY in the POLG mutant but failed to show increased expression of MT-TP, which was dramatically increased in the RNA-seq data. Conclusion We conclude that reduced expression of amyloid-associated mt-tRNAs is another indication of adaptive response to severe mitochondrial dysfunction in the POLG mutant. Incongruence between RNA-seq and northern blot measurement of MT-TP expression points towards the existence of mt-tRNA post-transcriptional modification regulation in the POLG mutant that alters either polyA capture or cDNA synthesis in RNA-seq library generation. Together, these data suggest that 1) evolution has distributed mt-tRNAs across the circular mitochondrial genome to allow chromosomal location-dependent mt-tRNA regulation (either by expression or PTM) and 2) this regulation is cognizant of the tRNA partner amino acid's amyloidogenic properties.
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Affiliation(s)
- M. Bilal Bayazit
- Department of Physiology & Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Ashley Francois
- Department of Physiology & Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Erin McGrail
- Department of Physiology & Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Federica Accornero
- Department of Physiology & Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Matthew S. Stratton
- Department of Physiology & Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
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Czarny P, Ziółkowska S, Kołodziej Ł, Watała C, Wigner-Jeziorska P, Bliźniewska-Kowalska K, Wachowska K, Gałecka M, Synowiec E, Gałecki P, Bijak M, Szemraj J, Śliwiński T. Single-Nucleotide Polymorphisms in Genes Maintaining the Stability of Mitochondrial DNA Affect the Occurrence, Onset, Severity and Treatment of Major Depressive Disorder. Int J Mol Sci 2023; 24:14752. [PMID: 37834200 PMCID: PMC10573273 DOI: 10.3390/ijms241914752] [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: 09/02/2023] [Revised: 09/26/2023] [Accepted: 09/27/2023] [Indexed: 10/15/2023] Open
Abstract
One of the key features of major depressive disorder (MDD, depression) is increased oxidative stress manifested by elevated levels of mtROS, a hallmark of mitochondrial dysfunction, which can arise from mitochondrial DNA (mtDNA) damage. Thus, the current study explores possibility that the single-nucleotide polymorphisms (SNPs) of genes encoding the three enzymes that are thought to be implicated in the replication, repair or degradation of mtDNA, i.e., POLG, ENDOG and EXOG, have an impact on the occurrence, onset, severity and treatment of MDD. Five SNPs were selected: EXOG c.-188T > G (rs9838614), EXOG c.*627G > A (rs1065800), POLG c.-1370T > A (rs1054875), ENDOG c.-394T > C (rs2977998) and ENDOG c.-220C > T (rs2997922), while genotyping was performed on 538 DNA samples (277 cases and 261 controls) using TaqMan probes. All SNPs of EXOG and ENDOG modulated the risk of depression, but the strongest effect was observed for rs1065800, while rs9838614 and rs2977998 indicate that they might influence the severity of symptoms, and, to a lesser extent, treatment effectiveness. Although the SNP located in POLG did not affect occurrence of the disease, the result suggests that it may influence the onset and treatment outcome. These findings further support the hypothesis that mtDNA damage and impairment in its metabolism play a crucial role not only in the development, but also in the treatment of depression.
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Affiliation(s)
- Piotr Czarny
- Department of Medical Biochemistry, Medical University of Lodz, 92-215 Lodz, Poland; (S.Z.); (J.S.)
| | - Sylwia Ziółkowska
- Department of Medical Biochemistry, Medical University of Lodz, 92-215 Lodz, Poland; (S.Z.); (J.S.)
| | - Łukasz Kołodziej
- Laboratory of Medical Genetics, Faculty of Biology and Environmental Protection, University of Lodz, 92-215 Lodz, Poland; (Ł.K.)
| | - Cezary Watała
- Department of Haemostatic Disorders, Medical University of Lodz, 92-215 Lodz, Poland;
| | - Paulina Wigner-Jeziorska
- Department of General Biochemistry, Faculty of Biology and Environmental Protection, University of Lodz, 90-136 Lodz, Poland;
| | | | - Katarzyna Wachowska
- Department of Adult Psychiatry, Medical University of Lodz, 91-229 Lodz, Poland; (K.B.-K.); (K.W.); (P.G.)
| | - Małgorzata Gałecka
- Department of Psychotherapy, Medical University of Lodz, 91-229 Lodz, Poland;
| | - Ewelina Synowiec
- Laboratory of Medical Genetics, Faculty of Biology and Environmental Protection, University of Lodz, 92-215 Lodz, Poland; (Ł.K.)
| | - Piotr Gałecki
- Department of Adult Psychiatry, Medical University of Lodz, 91-229 Lodz, Poland; (K.B.-K.); (K.W.); (P.G.)
| | - Michał Bijak
- Biohazard Prevention Centre, Faculty of Biology and Environmental Protection, University of Lodz, 90-136 Lodz, Poland;
| | - Janusz Szemraj
- Department of Medical Biochemistry, Medical University of Lodz, 92-215 Lodz, Poland; (S.Z.); (J.S.)
| | - Tomasz Śliwiński
- Laboratory of Medical Genetics, Faculty of Biology and Environmental Protection, University of Lodz, 92-215 Lodz, Poland; (Ł.K.)
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Zhu Y, Zhang JL, Yan XJ, Ji Y, Wang FF. Exploring a new mechanism between lactate and VSMC calcification: PARP1/POLG/UCP2 signaling pathway and imbalance of mitochondrial homeostasis. Cell Death Dis 2023; 14:598. [PMID: 37679327 PMCID: PMC10484939 DOI: 10.1038/s41419-023-06113-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 08/17/2023] [Accepted: 08/24/2023] [Indexed: 09/09/2023]
Abstract
Lactate leads to the imbalance of mitochondria homeostasis, which then promotes vascular calcification. PARP1 can upregulate osteogenic genes and accelerate vascular calcification. However, the relationship among lactate, PARP1, and mitochondrial homeostasis is unclear. The present study aimed to explore the new molecular mechanism of lactate to promote VSMC calcification by evaluating PARP1 as a breakthrough molecule. A coculture model of VECs and VSMCs was established, and the model revealed that the glycolysis ability and lactate production of VECs were significantly enhanced after incubation in DOM. Osteogenic marker expression, calcium deposition, and apoptosis in VSMCs were decreased after lactate dehydrogenase A knockdown in VECs. Mechanistically, exogenous lactate increased the overall level of PARP and PARylation in VSMCs. PARP1 knockdown inhibited Drp1-mediated mitochondrial fission and partially restored PINK1/Parkin-mediated mitophagy, thereby reducing mitochondrial oxidative stress. Moreover, lactate induced the translocation of PARP1 from the nucleus to the mitochondria, which then combined with POLG and inhibited POLG-mediated mitochondrial DNA synthesis. This process led to the downregulation of mitochondria-encoded genes, disturbance of mitochondrial respiration, and inhibition of oxidative phosphorylation. The knockdown of PARP1 could partially reverse the damage of mitochondrial gene expression and function caused by lactate. Furthermore, UCP2 was upregulated by the PARP1/POLG signal, and UCP2 knockdown inhibited Drp1-mediated mitochondrial fission and partially recovered PINK1/Parkin-mediated mitophagy. Finally, UCP2 knockdown in VSMCs alleviated DOM-caused VSMC calcification in the coculture model. The study results thus suggest that upregulated PARP1 is involved in the mechanism through which lactate accelerates VSMC calcification partly via POLG/UCP2-caused unbalanced mitochondrial homeostasis.
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Affiliation(s)
- Yi Zhu
- Department of Cardiology, The Affiliated Changzhou Second People's Hospital of Nanjing Medical University, Changzhou Second People's Hospital, Changzhou Medical Center, Nanjing Medical University, Changzhou, PR China
| | - Jia-Li Zhang
- Department of Gastroenterology Centre, The Affiliated Changzhou Second People's Hospital of Nanjing Medical University, Changzhou, PR China
| | - Xue-Jiao Yan
- Department of Cardiology, The Affiliated Changzhou Second People's Hospital of Nanjing Medical University, Changzhou Second People's Hospital, Changzhou Medical Center, Nanjing Medical University, Changzhou, PR China
| | - Yuan Ji
- Department of Cardiology, The Affiliated Changzhou Second People's Hospital of Nanjing Medical University, Changzhou Second People's Hospital, Changzhou Medical Center, Nanjing Medical University, Changzhou, PR China.
| | - Fang-Fang Wang
- Department of Cardiology, The Affiliated Changzhou Second People's Hospital of Nanjing Medical University, Changzhou Second People's Hospital, Changzhou Medical Center, Nanjing Medical University, Changzhou, PR China.
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