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Stoccoro A, Smith AR, Mosca L, Marocchi A, Gerardi F, Lunetta C, Cereda C, Gagliardi S, Lunnon K, Migliore L, Coppedè F. Reduced mitochondrial D-loop methylation levels in sporadic amyotrophic lateral sclerosis. Clin Epigenetics 2020; 12:137. [PMID: 32917270 PMCID: PMC7488473 DOI: 10.1186/s13148-020-00933-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 09/01/2020] [Indexed: 12/11/2022] Open
Abstract
Background Mitochondrial dysregulation and aberrant epigenetic mechanisms have been frequently reported in neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), and several researchers suggested that epigenetic dysregulation in mitochondrial DNA (mtDNA) could contribute to the neurodegenerative process. We recently screened families with mutations in the major ALS causative genes, namely C9orf72, SOD1, FUS, and TARDBP, observing reduced methylation levels of the mtDNA regulatory region (D-loop) only in peripheral lymphocytes of SOD1 carriers. However, until now no studies investigated the potential role of mtDNA methylation impairment in the sporadic form of ALS, which accounts for the majority of disease cases. The aim of the current study was to investigate the D-loop methylation levels and the mtDNA copy number in sporadic ALS patients and compare them to those observed in healthy controls and in familial ALS patients. Pyrosequencing analysis of D-loop methylation levels and quantitative analysis of mtDNA copy number were performed in peripheral white blood cells from 36 sporadic ALS patients, 51 age- and sex-matched controls, and 27 familial ALS patients with germinal mutations in SOD1 or C9orf72 that represent the major familial ALS forms. Results In the total sample, D-loop methylation levels were significantly lower in ALS patients compared to controls, and a significant inverse correlation between D-loop methylation levels and the mtDNA copy number was observed. Stratification of ALS patients into different subtypes revealed that both SOD1-mutant and sporadic ALS patients showed lower D-loop methylation levels compared to controls, while C9orf72-ALS patients showed similar D-loop methylation levels than controls. In healthy controls, but not in ALS patients, D-loop methylation levels decreased with increasing age at sampling and were higher in males compared to females. Conclusions Present data reveal altered D-loop methylation levels in sporadic ALS and confirm previous evidence of an inverse correlation between D-loop methylation levels and the mtDNA copy number, as well as differences among the major familial ALS subtypes. Overall, present results suggest that D-loop methylation and mitochondrial replication are strictly related to each other and could represent compensatory mechanisms to counteract mitochondrial impairment in sporadic and SOD1-related ALS forms.
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Affiliation(s)
- Andrea Stoccoro
- Department of Translational Research and of New Surgical and Medical Technologies, Lab. of Medical Genetics, University of Pisa, Medical School, Via Roma 55, 56126, Pisa, Italy
| | - Adam R Smith
- University of Exeter Medical School, College of Medicine and Health, Exeter University, Exeter, UK
| | - Lorena Mosca
- Medical Genetics Unit, Department of Laboratory Medicine, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy
| | - Alessandro Marocchi
- Medical Genetics Unit, Department of Laboratory Medicine, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy
| | | | | | - Cristina Cereda
- Genomic and Post-Genomic Center, IRCCS Mondino Foundation, Via Mondino 2, 27100, Pavia, Italy
| | - Stella Gagliardi
- Genomic and Post-Genomic Center, IRCCS Mondino Foundation, Via Mondino 2, 27100, Pavia, Italy
| | - Katie Lunnon
- University of Exeter Medical School, College of Medicine and Health, Exeter University, Exeter, UK
| | - Lucia Migliore
- Department of Translational Research and of New Surgical and Medical Technologies, Lab. of Medical Genetics, University of Pisa, Medical School, Via Roma 55, 56126, Pisa, Italy
| | - Fabio Coppedè
- Department of Translational Research and of New Surgical and Medical Technologies, Lab. of Medical Genetics, University of Pisa, Medical School, Via Roma 55, 56126, Pisa, Italy.
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Stoccoro A, Mosca L, Carnicelli V, Cavallari U, Lunetta C, Marocchi A, Migliore L, Coppedè F. Mitochondrial DNA copy number and D-loop region methylation in carriers of amyotrophic lateral sclerosis gene mutations. Epigenomics 2018; 10:1431-1443. [PMID: 30088417 DOI: 10.2217/epi-2018-0072] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
AIM To investigate mitochondrial DNA (mtDNA) copy number and D-loop region methylation in carriers of SOD1, TARDBP, FUS and C9orf72 mutations. METHODS Investigations were performed in blood DNA from 114 individuals, including amyotrophic lateral sclerosis (ALS) patients, presymptomatic carriers and noncarrier family members. RESULTS Increased mtDNA copy number (p = 0.0001) was observed in ALS patients, and particularly in those with SOD1 or C9orf72 mutations. SOD1 mutation carriers showed also a significant decrease in D-loop methylation levels (p = 0.003). An inverse correlation between D-loop methylation levels and the mtDNA copy number (p = 0.0005) was observed. CONCLUSION Demethylation of the D-loop region could represent a compensatory mechanism for mtDNA upregulation in carriers of ALS-linked SOD1 mutations.
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Affiliation(s)
- Andrea Stoccoro
- Department of Translational Research & New Technologies in Medicine & Surgery, Medical Genetics Laboratory, University of Pisa, Pisa, Italy.,Doctoral School in Genetics Oncology & Clinical Medicine, Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Lorena Mosca
- Medical Genetics Unit, Department of Laboratory Medicine, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy
| | - Vittoria Carnicelli
- Department of Surgical, Medical & Molecular Pathology & Critical Care Medicine, University of Pisa, Pisa, Italy
| | - Ugo Cavallari
- Medical Genetics Unit, Department of Laboratory Medicine, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy
| | - Christian Lunetta
- NEuroMuscular Omnicentre (NEMO), ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy
| | - Alessandro Marocchi
- Medical Genetics Unit, Department of Laboratory Medicine, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy
| | - Lucia Migliore
- Department of Translational Research & New Technologies in Medicine & Surgery, Medical Genetics Laboratory, University of Pisa, Pisa, Italy
| | - Fabio Coppedè
- Department of Translational Research & New Technologies in Medicine & Surgery, Medical Genetics Laboratory, University of Pisa, Pisa, Italy
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