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Matsumoto S, Uchiumi T, Noda N, Ueyanagi Y, Hotta T, Kang D. Droplet digital polymerase chain reaction to measure heteroplasmic m.3243A>G mitochondrial mutations. Lab Med 2024; 55:227-233. [PMID: 37478467 PMCID: PMC10920975 DOI: 10.1093/labmed/lmad063] [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] [Indexed: 07/23/2023] Open
Abstract
OBJECTIVE Different mitochondrial DNA genotypes can coexist in a cell population as well as in a single cell, a condition known as heteroplasmy. Here, we accurately determined the heteroplasmy levels of the m.3243A>G mutation, which is the most frequently identified mutation in patients with mitochondrial diseases, using droplet digital polymerase chain reaction (ddPCR). METHODS The m.3243A>G heteroplasmy levels in artificial heteroplasmy controls mixed with various proportions of wild-type and mutant plasmids were measured using ddPCR, PCR-restriction fragment length polymorphism, and Sanger sequencing. The m.3243A>G heteroplasmy levels in DNA, extracted from the peripheral blood of patients with suspected mitochondrial disease and healthy subjects, were determined using ddPCR. RESULTS The accuracy of the ddPCR method was high. The lower limit of detection was 0.1%, which indicated its higher sensitivity compared with other methods. The m.3243A>G heteroplasmy levels in peripheral blood, measured using ddPCR, correlated inversely with age at the time of analysis. The m.3243A>G mutation may be overlooked in the peripheral blood-derived DNA of elderly people, as patients >60 years of age have heteroplasmy levels <10%, which is difficult to detect using methods other than the highly sensitive ddPCR. CONCLUSION ddPCR may be considered an accurate and sensitive method for measuring m.3243 A>G heteroplasmy levels of mitochondrial DNA.
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Affiliation(s)
- Shinya Matsumoto
- Department of Clinical Chemistry and Laboratory Medicine, Kyushu University Hospital, Fukuoka, Japan
| | - Takeshi Uchiumi
- Department of Clinical Chemistry and Laboratory Medicine, Kyushu University Hospital, Fukuoka, Japan
- Department of Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
- Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Nozomi Noda
- Department of Clinical Chemistry and Laboratory Medicine, Kyushu University Hospital, Fukuoka, Japan
| | - Yasushi Ueyanagi
- Department of Clinical Chemistry and Laboratory Medicine, Kyushu University Hospital, Fukuoka, Japan
| | - Taeko Hotta
- Department of Clinical Chemistry and Laboratory Medicine, Kyushu University Hospital, Fukuoka, Japan
| | - Dongchon Kang
- Department of Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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2
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Sun X, Bulekova K, Yang J, Lai M, Pitsillides AN, Liu X, Zhang Y, Guo X, Yong Q, Raffield LM, Rotter JI, Rich SS, Abecasis G, Carson AP, Vasan RS, Bis JC, Psaty BM, Boerwinkle E, Fitzpatrick AL, Satizabal CL, Arking DE, Ding J, Levy D, Liu C. Association analysis of mitochondrial DNA heteroplasmic variants: methods and application. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.01.12.24301233. [PMID: 38260412 PMCID: PMC10802757 DOI: 10.1101/2024.01.12.24301233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
We rigorously assessed a comprehensive association testing framework for heteroplasmy, employing both simulated and real-world data. This framework employed a variant allele fraction (VAF) threshold and harnessed multiple gene-based tests for robust identification and association testing of heteroplasmy. Our simulation studies demonstrated that gene-based tests maintained an appropriate type I error rate at α=0.001. Notably, when 5% or more heteroplasmic variants within a target region were linked to an outcome, burden-extension tests (including the adaptive burden test, variable threshold burden test, and z-score weighting burden test) outperformed the sequence kernel association test (SKAT) and the original burden test. Applying this framework, we conducted association analyses on whole-blood derived heteroplasmy in 17,507 individuals of African and European ancestries (31% of African Ancestry, mean age of 62, with 58% women) with whole genome sequencing data. We performed both cohort- and ancestry-specific association analyses, followed by meta-analysis on both pooled samples and within each ancestry group. Our results suggest that mtDNA-encoded genes/regions are likely to exhibit varying rates in somatic aging, with the notably strong associations observed between heteroplasmy in the RNR1 and RNR2 genes (p<0.001) and advance aging by the Original Burden test. In contrast, SKAT identified significant associations (p<0.001) between diabetes and the aggregated effects of heteroplasmy in several protein-coding genes. Further research is warranted to validate these findings. In summary, our proposed statistical framework represents a valuable tool for facilitating association testing of heteroplasmy with disease traits in large human populations.
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Affiliation(s)
- Xianbang Sun
- Department of Biostatistics, School of Public Health, Boston University, Boston, MA 02118, USA
| | - Katia Bulekova
- Research Computing Services, Boston University, Boston, MA 02215, USA
| | - Jian Yang
- Department of Biostatistics, School of Public Health, Boston University, Boston, MA 02118, USA
| | - Meng Lai
- Department of Biostatistics, School of Public Health, Boston University, Boston, MA 02118, USA
| | | | - Xue Liu
- Department of Biostatistics, School of Public Health, Boston University, Boston, MA 02118, USA
| | - Yuankai Zhang
- Department of Biostatistics, School of Public Health, Boston University, Boston, MA 02118, USA
| | - Xiuqing Guo
- The Institute for Translational Genomics and Population Sciences, Department of Pediatrics, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Qian Yong
- Longitudinal Studies Section, Translational Gerontology Branch, NIA/NIH, Baltimore, MD 21224, USA
| | - Laura M. Raffield
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA
| | - Jerome I. Rotter
- The Institute for Translational Genomics and Population Sciences, Department of Pediatrics, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Stephen S. Rich
- Department of Public Health Services, Center for Public Health Genomics, University of Virginia, Charlottesville, VA 22908, USA
| | - Goncalo Abecasis
- TOPMed Informatics Research Center, University of Michigan, Ann Arbor, MI 48109, USA
| | - April P. Carson
- Department of Medicine, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Ramachandran S. Vasan
- Sections of Preventive Medicine and Epidemiology, and Cardiovascular Medicine, Boston University School of Medicine, Boston, MA, 02118, USA
- Framingham Heart Study, NHLBI/NIH, Framingham, MA 01702, USA
| | - Joshua C. Bis
- Cardiovascular Health Research Unit, Department of Medicine, University of Washington, Seattle, WA 98101, USA
| | - Bruce M. Psaty
- Cardiovascular Health Research Unit, Department of Medicine, University of Washington, Seattle, WA 98101, USA
- Departments of Epidemiology, and Health Services, University of Washington, Seattle, WA 98101, USA
| | - Eric Boerwinkle
- Human Genetics Center, Department of Epidemiology, Human Genetics and Environmental Sciences, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Annette L. Fitzpatrick
- Departments of Family Medicine, Epidemiology, and Global Health, University of Washington, Seattle, WA 98195, USA
| | - Claudia L. Satizabal
- Framingham Heart Study, NHLBI/NIH, Framingham, MA 01702, USA
- Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Dan E. Arking
- McKusick-Nathans Institute, Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, MD 21205, USA
| | - Jun Ding
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA
| | - Daniel Levy
- Framingham Heart Study, NHLBI/NIH, Framingham, MA 01702, USA
- Population Sciences Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | | | - Chunyu Liu
- Department of Biostatistics, School of Public Health, Boston University, Boston, MA 02118, USA
- Framingham Heart Study, NHLBI/NIH, Framingham, MA 01702, USA
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3
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Yagi K, Okazaki S, Ohbatake A, Nakaya M, Liu J, Arite E, Miyamoto Y, Ito N, Nakano K, Yamaaki N, Honoki H, Fujisaka S, Chujo D, Tsunoda SI, Yanagimoto K, Nozue T, Yamada M, Ooe K, Araki T, Nakashima A, Azami Y, Sodemoto Y, Tadokoro K, Nagano M, Noguchi T, Nohara A, Origasa H, Niida Y, Tada H. Negative correlation between organ heteroplasmy, particularly hepatic heteroplasmy, and age at death revealed by post-mortem studies of m.3243A > G cases. Mol Genet Metab 2023; 140:107691. [PMID: 37660570 DOI: 10.1016/j.ymgme.2023.107691] [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: 04/27/2023] [Revised: 08/27/2023] [Accepted: 08/27/2023] [Indexed: 09/05/2023]
Abstract
Mitochondrial DNA m.3243A > G mutation causes mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) and its associated multi-organ disorders, including diabetes. To clarify associations between m.3243A > G organ heteroplasmy and clinical phenotypes, including the age at death, we combined genetic and pathological examinations from seven unreported and 36 literature cases of autopsied subjects. Clinical characteristics of subjects were as follows: male, 13; female, 28; unknown, 2; the age at death, 36.9 ± 20.2 [4-82] years; BMI, 16.0 ± 2.9 [13.0-22.3]; diabetes, N = 21 (49%), diabetes onset age 38.6 ± 14.2 years; deafness, N = 27 (63%); stroke-like episodes (StLEp), N = 25 (58%); congestive heart failure (CHF), N = 15 (35%); CHF onset age, 51.3 ± 14.5 years. Causes of death (N = 32) were as follows: cardiac, N = 13 (41%); infection, N = 8 (25%); StLEp, N = 4 (13%); gastrointestinal, N = 4 (13%); renal, N = 2 (6%); hepatic, N = 1 (2%). High and low heteroplasmies were confirmed in non-regenerative and regenerative organs, respectively. Heteroplasmy of the liver, spleen, leukocytes, and kidney for all subjects was significantly associated with the age at death. Furthermore, the age at death was related to juvenile-onset (any m.3243A > G-related symptoms appeared before 20) and stroke-like episodes. Multiple linear regression analysis with the age at death as an objective variable showed the significant contribution of liver heteroplasty and juvenile-onset to the age at death. m.3243A > G organ heteroplasmy levels, particularly hepatic heteroplasmy, are significantly associated with the age at death in deceased cases.
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Affiliation(s)
- Kunimasa Yagi
- Center for Clinical Genomics, Kanazawa Medical University Hospital, 1-1 Daigaku, Uchinada, Ishikawa 920-0293, Japan; Second Department of Internal Medicine, Kanazawa University Graduate School of Medical Science, Kanazawa 920-8641, Japan; First Department of Internal Medicine, Toyama University, Toyama 934-0194, Japan.
| | - Satoko Okazaki
- Second Department of Internal Medicine, Kanazawa University Graduate School of Medical Science, Kanazawa 920-8641, Japan
| | - Azusa Ohbatake
- Second Department of Internal Medicine, Kanazawa University Graduate School of Medical Science, Kanazawa 920-8641, Japan
| | - Masako Nakaya
- Second Department of Internal Medicine, Kanazawa University Graduate School of Medical Science, Kanazawa 920-8641, Japan
| | - Jianhui Liu
- Second Department of Internal Medicine, Kanazawa University Graduate School of Medical Science, Kanazawa 920-8641, Japan; First Department of Internal Medicine, Toyama University, Toyama 934-0194, Japan
| | - Eiko Arite
- Second Department of Internal Medicine, Kanazawa University Graduate School of Medical Science, Kanazawa 920-8641, Japan
| | - Yukiko Miyamoto
- Second Department of Internal Medicine, Kanazawa University Graduate School of Medical Science, Kanazawa 920-8641, Japan
| | - Naoko Ito
- Second Department of Internal Medicine, Kanazawa University Graduate School of Medical Science, Kanazawa 920-8641, Japan
| | - Kaoru Nakano
- Second Department of Internal Medicine, Kanazawa University Graduate School of Medical Science, Kanazawa 920-8641, Japan
| | - Naoto Yamaaki
- Second Department of Internal Medicine, Kanazawa University Graduate School of Medical Science, Kanazawa 920-8641, Japan
| | - Hisae Honoki
- First Department of Internal Medicine, Toyama University, Toyama 934-0194, Japan
| | - Shiho Fujisaka
- First Department of Internal Medicine, Toyama University, Toyama 934-0194, Japan
| | - Daisuke Chujo
- Second Department of Internal Medicine, Kanazawa University Graduate School of Medical Science, Kanazawa 920-8641, Japan; First Department of Internal Medicine, Toyama University, Toyama 934-0194, Japan
| | - Shin-Ichiro Tsunoda
- Yokohama Sakae Kyosai Hospital, Federation of National Public Service Personnel Mutual Associations, Yokohama 247-8581, Japan
| | - Kunio Yanagimoto
- Yokohama Sakae Kyosai Hospital, Federation of National Public Service Personnel Mutual Associations, Yokohama 247-8581, Japan
| | - Tsuyoshi Nozue
- Yokohama Sakae Kyosai Hospital, Federation of National Public Service Personnel Mutual Associations, Yokohama 247-8581, Japan
| | - Masayo Yamada
- Yokohama Sakae Kyosai Hospital, Federation of National Public Service Personnel Mutual Associations, Yokohama 247-8581, Japan
| | - Kotaro Ooe
- Department of Internal Medicine, Saiseikai Kanazawa Hospital, Kanazawa 920-0353, Japan
| | - Tsutomu Araki
- Department of Internal Medicine, Saiseikai Kanazawa Hospital, Kanazawa 920-0353, Japan
| | - Akikatsu Nakashima
- Department of Internal Medicine, Ishikawa Prefectural Central Hospital, Kanazawa 920-8530, Japan
| | | | | | - Kenichi Tadokoro
- Bio Medical Laboratory (BML), Inc., 1361-1 Matoba, Kawagoe, Saitama 350-1101, Japan
| | - Makoto Nagano
- Bio Medical Laboratory (BML), Inc., 1361-1 Matoba, Kawagoe, Saitama 350-1101, Japan
| | - Tohru Noguchi
- Second Department of Internal Medicine, Kanazawa University Graduate School of Medical Science, Kanazawa 920-8641, Japan
| | - Atushi Nohara
- Department of Internal Medicine, Ishikawa Prefectural Central Hospital, Kanazawa 920-8530, Japan
| | - Hideki Origasa
- The Institute of Statistical Mathematics, Toyama University, Toyama 934-0194, Japan
| | - Yo Niida
- Center for Clinical Genomics, Kanazawa Medical University Hospital, 1-1 Daigaku, Uchinada, Ishikawa 920-0293, Japan
| | - Hayato Tada
- Second Department of Internal Medicine, Kanazawa University Graduate School of Medical Science, Kanazawa 920-8641, Japan
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4
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Berry BJ. A mitochondrial origin for inherited diabetes mellitus. Nat Rev Endocrinol 2023:10.1038/s41574-023-00856-x. [PMID: 37237046 DOI: 10.1038/s41574-023-00856-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Affiliation(s)
- Brandon J Berry
- University of Washington Medical Center, Department of Laboratory Medicine and Pathology, Seattle, WA, USA.
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5
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Ng YS, Gorman GS. Stroke-like episodes in adult mitochondrial disease. HANDBOOK OF CLINICAL NEUROLOGY 2023; 194:65-78. [PMID: 36813321 DOI: 10.1016/b978-0-12-821751-1.00005-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Stroke-like episode is a paroxysmal neurological manifestation which affects a specific group of patients with mitochondrial disease. Focal-onset seizures, encephalopathy, and visual disturbances are prominent findings associated with stroke-like episodes, with a predilection for the posterior cerebral cortex. The most common cause of stroke-like episodes is the m.3243A>G variant in MT-TL1 gene followed by recessive POLG variants. This chapter aims to review the definition of stroke-like episode and delineate the clinical phenomenology, neuroimaging and EEG findings typically seen in patients. In addition, several lines of evidence supporting neuronal hyper-excitability as the key mechanism of stroke-like episodes are discussed. The management of stroke-like episodes should focus on aggressive seizure management and treatment for concomitant complications such as intestinal pseudo-obstruction. There is no robust evidence to prove the efficacy of l-arginine for both acute and prophylactic settings. Progressive brain atrophy and dementia are the sequalae of recurrent stroke-like episode, and the underlying genotype in part predicts prognosis.
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Affiliation(s)
- Yi Shiau Ng
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Gráinne S Gorman
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom.
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6
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Liu Y, Zhao S, Chen X, Bian Y, Cao Y, Xu P, Zhang C, Zhang J, Zhao S, Zhao H. Variations in mitochondrial DNA coding and D-loop region are associated with early embryonic development defects in infertile women. Hum Genet 2023; 142:193-200. [PMID: 36352239 DOI: 10.1007/s00439-022-02505-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 10/31/2022] [Indexed: 11/11/2022]
Abstract
Mitochondrial DNA (mtDNA) plays a critical role in oocyte maturation, fertilization, and early embryonic development. Defects in mtDNA may determine the alteration of the mitochondrial function, affecting cellular oxidative phosphorylation and ATP supply, leading to impaired oocyte maturation, abnormal fertilization, and low embryonic developmental potential, ultimately leading to female infertility. This case-control study was established to investigate the correlation between mtDNA variations and early embryonic development defects. Peripheral blood was collected for next-generation sequencing from women who suffered the repeated failures of in vitro fertilization (IVF) and/or intracytoplasmic sperm injection (ICSI) cycles due to early embryonic development defects as well as in-house healthy controls, and the sequencing results were statistically analyzed for all subjects. This study found that infertile women with early embryonic development defects carried more mtDNA variants, especially in the D-loop region, ATP6 gene, and CYTB gene. By univariate logistic regression analysis, 16 mtDNA variants were associated with an increased risk of early embryonic development defects (OR > 1, p < 0.05). Furthermore, we identified 16 potentially pathogenic mtDNA variants only in infertile cases. The data proved that mtDNA variations were associated with early embryonic development defects in infertile Chinese women.
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Affiliation(s)
- Yuqing Liu
- Center for Reproductive Medicine, Shandong University, 157 Jingliu Road, Jinan, 250021, Shandong, China.,Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China.,Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China.,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China.,Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China.,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
| | - Shuai Zhao
- Center for Reproductive Medicine, Shandong University, 157 Jingliu Road, Jinan, 250021, Shandong, China.,Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China.,Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China.,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China.,Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China.,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
| | - Xiaolei Chen
- Center for Reproductive Medicine, Shandong University, 157 Jingliu Road, Jinan, 250021, Shandong, China.,Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China.,Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China.,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China.,Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China.,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
| | - Yuehong Bian
- Center for Reproductive Medicine, Shandong University, 157 Jingliu Road, Jinan, 250021, Shandong, China.,Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China.,Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China.,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China.,Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China.,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
| | - Yongzhi Cao
- Center for Reproductive Medicine, Shandong University, 157 Jingliu Road, Jinan, 250021, Shandong, China.,Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China.,Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China.,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China.,Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China.,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
| | - Peiwen Xu
- Center for Reproductive Medicine, Shandong University, 157 Jingliu Road, Jinan, 250021, Shandong, China.,Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China.,Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China.,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China.,Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China.,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
| | - Changming Zhang
- Center for Reproductive Medicine, Shandong University, 157 Jingliu Road, Jinan, 250021, Shandong, China.,Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China.,Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China.,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China.,Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China.,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
| | - Jiangtao Zhang
- Center for Reproductive Medicine, Shandong University, 157 Jingliu Road, Jinan, 250021, Shandong, China.,Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China.,Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China.,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China.,Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China.,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
| | - Shigang Zhao
- Center for Reproductive Medicine, Shandong University, 157 Jingliu Road, Jinan, 250021, Shandong, China.,Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China.,Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China.,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China.,Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China.,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
| | - Han Zhao
- Center for Reproductive Medicine, Shandong University, 157 Jingliu Road, Jinan, 250021, Shandong, China. .,Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China. .,Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China. .,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China. .,Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China. .,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China.
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7
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Roesch S, O'Sullivan A, Zimmermann G, Mair A, Lipuš C, Mayr JA, Wortmann SB, Rasp G. Mitochondrial Disease and Hearing Loss in Children: A Systematic Review. Laryngoscope 2022; 132:2459-2472. [PMID: 35188226 PMCID: PMC9790539 DOI: 10.1002/lary.30067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 02/01/2022] [Accepted: 02/04/2022] [Indexed: 12/30/2022]
Abstract
OBJECTIVES Hearing loss is a clinical symptom, frequently mentioned in the context of mitochondrial disease. With no cure available for mitochondrial disease, supportive treatment of clinical symptoms like hearing loss is of the utmost importance. The aim of this study was to summarize current knowledge on hearing loss in genetically proven mitochondrial disease in children and deduce possible and necessary consequences in patient care. METHODS Systematic literature review, including Medline, Embase, and Cochrane library. Review protocol was established and registered prior to conduction (International prospective register of systematic reviews-PROSPERO: CRD42020165356). Conduction of this review was done in accordance with MOOSE criteria. RESULTS A total of 23 articles, meeting predefined criteria and providing sufficient information on 75 individuals with childhood onset hearing loss was included for analysis. Both cochlear and retro-cochlear origin of hearing loss can be identified among different types of mitochondrial disease. Analysis was hindered by inhomogeneous reporting and methodical limitations. CONCLUSION Overall, the findings do not allow for a general statement on hearing loss in children with mitochondrial disease. Retro-cochlear hearing loss seems to be found more often than expected. A common feature appears to be progression of hearing loss over time. However, hearing loss in these patients shows manifold characteristics. Therefore, awareness of mitochondrial disease as a possible causative background is important for otolaryngologists. Future attempts rely on standardized reporting and long-term follow-up. LEVEL OF EVIDENCE NA Laryngoscope, 132:2459-2472, 2022.
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Affiliation(s)
- Sebastian Roesch
- Department of Otorhinolaryngology, Head and Neck SurgeryParacelsus Medical UniversitySalzburgAustria
| | - Anna O'Sullivan
- Department of Otorhinolaryngology, Head and Neck SurgeryParacelsus Medical UniversitySalzburgAustria,Insitute of PathologyParacelsus Medical UniversitySalzburgAustria
| | - Georg Zimmermann
- Team Biostatistics and Big Medical Data, IDA Lab SalzburgParacelsus Medical UniversitySalzburgAustria,Department of Research and InnovationParacelsus Medical UniversitySalzburgAustria
| | - Alois Mair
- Department of Otorhinolaryngology, Head and Neck SurgeryParacelsus Medical UniversitySalzburgAustria
| | - Cvetka Lipuš
- PMU University LibraryParacelsus Medical UniversitySalzburgAustria
| | - Johannes A. Mayr
- University Children's HospitalParacelsus Medical UniversitySalzburgAustria
| | - Saskia B. Wortmann
- University Children's HospitalParacelsus Medical UniversitySalzburgAustria,Amalia Children's Hospital, RadboudumcNijmegenThe Netherlands
| | - Gerd Rasp
- Department of Otorhinolaryngology, Head and Neck SurgeryParacelsus Medical UniversitySalzburgAustria
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8
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Ng YS, Lim AZ, Panagiotou G, Turnbull DM, Walker M. Endocrine Manifestations and New Developments in Mitochondrial Disease. Endocr Rev 2022; 43:583-609. [PMID: 35552684 PMCID: PMC9113134 DOI: 10.1210/endrev/bnab036] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Indexed: 11/19/2022]
Abstract
Mitochondrial diseases are a group of common inherited diseases causing disruption of oxidative phosphorylation. Some patients with mitochondrial disease have endocrine manifestations, with diabetes mellitus being predominant but also include hypogonadism, hypoadrenalism, and hypoparathyroidism. There have been major developments in mitochondrial disease over the past decade that have major implications for all patients. The collection of large cohorts of patients has better defined the phenotype of mitochondrial diseases and the majority of patients with endocrine abnormalities have involvement of several other systems. This means that patients with mitochondrial disease and endocrine manifestations need specialist follow-up because some of the other manifestations, such as stroke-like episodes and cardiomyopathy, are potentially life threatening. Also, the development and follow-up of large cohorts of patients means that there are clinical guidelines for the management of patients with mitochondrial disease. There is also considerable research activity to identify novel therapies for the treatment of mitochondrial disease. The revolution in genetics, with the introduction of next-generation sequencing, has made genetic testing more available and establishing a precise genetic diagnosis is important because it will affect the risk for involvement for different organ systems. Establishing a genetic diagnosis is also crucial because important reproductive options have been developed that will prevent the transmission of mitochondrial disease because of mitochondrial DNA variants to the next generation.
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Affiliation(s)
- Yi Shiau Ng
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Albert Zishen Lim
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Grigorios Panagiotou
- Department of Diabetes and Endocrinology, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Doug M Turnbull
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Mark Walker
- Department of Diabetes and Endocrinology, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
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9
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Cai N, Gomez-Duran A, Yonova-Doing E, Kundu K, Burgess AI, Golder ZJ, Calabrese C, Bonder MJ, Camacho M, Lawson RA, Li L, Williams-Gray CH, Di Angelantonio E, Roberts DJ, Watkins NA, Ouwehand WH, Butterworth AS, Stewart ID, Pietzner M, Wareham NJ, Langenberg C, Danesh J, Walter K, Rothwell PM, Howson JMM, Stegle O, Chinnery PF, Soranzo N. Mitochondrial DNA variants modulate N-formylmethionine, proteostasis and risk of late-onset human diseases. Nat Med 2021; 27:1564-1575. [PMID: 34426706 DOI: 10.1038/s41591-021-01441-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 06/15/2021] [Indexed: 02/02/2023]
Abstract
Mitochondrial DNA (mtDNA) variants influence the risk of late-onset human diseases, but the reasons for this are poorly understood. Undertaking a hypothesis-free analysis of 5,689 blood-derived biomarkers with mtDNA variants in 16,220 healthy donors, here we show that variants defining mtDNA haplogroups Uk and H4 modulate the level of circulating N-formylmethionine (fMet), which initiates mitochondrial protein translation. In human cytoplasmic hybrid (cybrid) lines, fMet modulated both mitochondrial and cytosolic proteins on multiple levels, through transcription, post-translational modification and proteolysis by an N-degron pathway, abolishing known differences between mtDNA haplogroups. In a further 11,966 individuals, fMet levels contributed to all-cause mortality and the disease risk of several common cardiovascular disorders. Together, these findings indicate that fMet plays a key role in common age-related disease through pleiotropic effects on cell proteostasis.
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Affiliation(s)
- Na Cai
- Human Genetics Department, Wellcome Sanger Institute (WT), Hinxton, UK.,European Bioinformatics Institute (EMBL-EBI), Hinxton, UK.,Helmholtz Pioneer Campus, Helmholtz Zentrum München, Neuherberg, Germany
| | - Aurora Gomez-Duran
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.,Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.,Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CIB-CSIC), Madrid, Spain
| | - Ekaterina Yonova-Doing
- British Heart Foundation Cardiovascular Epidemiology Unit, Department of Primary Public Health and Primary Care, University of Cambridge, Cambridge, UK.,Department of Genetics, Novo Nordisk Research Centre Oxford, Oxford, UK
| | - Kousik Kundu
- Human Genetics Department, Wellcome Sanger Institute (WT), Hinxton, UK
| | - Annette I Burgess
- Wolfson Centre for Prevention of Stroke and Dementia, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Zoe J Golder
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.,Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Claudia Calabrese
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.,Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Marc J Bonder
- European Bioinformatics Institute (EMBL-EBI), Hinxton, UK.,Division of Computational Genomics and Systems Genetics, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Marta Camacho
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Rachael A Lawson
- Translational and Clinical Research Institute, Newcastle University, Newcastle, UK
| | - Lixin Li
- Wolfson Centre for Prevention of Stroke and Dementia, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Caroline H Williams-Gray
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | | | - Emanuele Di Angelantonio
- British Heart Foundation Cardiovascular Epidemiology Unit, Department of Primary Public Health and Primary Care, University of Cambridge, Cambridge, UK.,British Heart Foundation Centre of Research Excellence, University of Cambridge, Cambridge, UK.,National Institute for Health Research Blood and Transplant Research Unit in Donor Health and Genomics, University of Cambridge, Cambridge, UK.,Health Data Research UK Cambridge, Wellcome Genome Campus and University of Cambridge, Cambridge, UK
| | - David J Roberts
- National Institute for Health Research Blood and Transplant Research Unit in Donor Health and Genomics, University of Cambridge, Cambridge, UK.,NHS Blood and Transplant-Oxford Centre, John Radcliffe Hospital, Oxford, UK.,Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Nick A Watkins
- NHS Blood and Transplant, Cambridge Biomedical Campus, Cambridge, UK
| | - Willem H Ouwehand
- Human Genetics Department, Wellcome Sanger Institute (WT), Hinxton, UK.,British Heart Foundation Centre of Research Excellence, University of Cambridge, Cambridge, UK.,NHS Blood and Transplant, Cambridge Biomedical Campus, Cambridge, UK.,Department of Haematology, University of Cambridge, Cambridge, UK
| | - Adam S Butterworth
- British Heart Foundation Cardiovascular Epidemiology Unit, Department of Primary Public Health and Primary Care, University of Cambridge, Cambridge, UK.,British Heart Foundation Centre of Research Excellence, University of Cambridge, Cambridge, UK.,National Institute for Health Research Blood and Transplant Research Unit in Donor Health and Genomics, University of Cambridge, Cambridge, UK.,Health Data Research UK Cambridge, Wellcome Genome Campus and University of Cambridge, Cambridge, UK
| | | | - Maik Pietzner
- MRC Epidemiology Unit, University of Cambridge, Cambridge, UK
| | - Nick J Wareham
- MRC Epidemiology Unit, University of Cambridge, Cambridge, UK
| | | | - John Danesh
- Human Genetics Department, Wellcome Sanger Institute (WT), Hinxton, UK.,British Heart Foundation Cardiovascular Epidemiology Unit, Department of Primary Public Health and Primary Care, University of Cambridge, Cambridge, UK.,British Heart Foundation Centre of Research Excellence, University of Cambridge, Cambridge, UK.,National Institute for Health Research Blood and Transplant Research Unit in Donor Health and Genomics, University of Cambridge, Cambridge, UK.,Health Data Research UK Cambridge, Wellcome Genome Campus and University of Cambridge, Cambridge, UK
| | - Klaudia Walter
- Human Genetics Department, Wellcome Sanger Institute (WT), Hinxton, UK
| | - Peter M Rothwell
- Wolfson Centre for Prevention of Stroke and Dementia, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Joanna M M Howson
- British Heart Foundation Cardiovascular Epidemiology Unit, Department of Primary Public Health and Primary Care, University of Cambridge, Cambridge, UK.,Department of Genetics, Novo Nordisk Research Centre Oxford, Oxford, UK
| | - Oliver Stegle
- European Bioinformatics Institute (EMBL-EBI), Hinxton, UK. .,Division of Computational Genomics and Systems Genetics, German Cancer Research Center (DKFZ), Heidelberg, Germany. .,European Molecular Biology Laboratory, Heidelberg, Germany.
| | - Patrick F Chinnery
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK. .,Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.
| | - Nicole Soranzo
- Human Genetics Department, Wellcome Sanger Institute (WT), Hinxton, UK. .,British Heart Foundation Centre of Research Excellence, University of Cambridge, Cambridge, UK. .,National Institute for Health Research Blood and Transplant Research Unit in Donor Health and Genomics, University of Cambridge, Cambridge, UK. .,Department of Haematology, University of Cambridge, Cambridge, UK. .,Genomics Research Centre, Human Technopole, Milan, Italy.
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10
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Gutiérrez Cortés N, Pertuiset C, Dumon E, Börlin M, Da Costa B, Le Guédard M, Stojkovic T, Loundon N, Rouillon I, Nadjar Y, Letellier T, Jonard L, Marlin S, Rocher C. Mutation m.3395A > G in MT-ND1 leads to variable pathologic manifestations. Hum Mol Genet 2021; 29:980-989. [PMID: 32011699 DOI: 10.1093/hmg/ddaa020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 01/27/2020] [Accepted: 01/31/2020] [Indexed: 11/12/2022] Open
Abstract
A non-synonymous mtDNA mutation, m.3395A > G, which changes tyrosine in position 30 to cysteine in p.MT-ND1, was found in several patients with a wide range of clinical phenotypes such as deafness, diabetes and cerebellar syndrome but no Leber's hereditary optic neuropathy. Although this mutation has already been described, its pathogenicity has not been demonstrated. Here, it was found isolated for the first time, allowing a study to investigate its pathogenicity. To do so, we constructed cybrid cell lines and carried out a functional study to assess the possible consequences of the mutation on mitochondrial bioenergetics. Results obtained demonstrated that this mutation causes an important dysfunction of the mitochondrial respiratory chain with a decrease in both activity and quantity of complex I due to a diminution of p.MT-ND1 quantity. However, no subcomplexes were found in cybrids carrying the mutation, indicating that the quality of the complex I assembly is not affected. Moreover, based on the crystal structure of p.MT-ND1 and the data found in the literature, we propose a hypothesis for the mechanism of the degradation of p.MT-ND1. Our study provides new insights into the pathophysiology of mitochondrial diseases and in particular of MT-ND1 mutations.
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Affiliation(s)
- Nicolás Gutiérrez Cortés
- INSERM-U688 Physiopathologie Mitochondriale, Université Bordeaux Segalen, 146 rue Léo Saignat, 33076 Bordeaux, France
| | - Claire Pertuiset
- INSERM-U688 Physiopathologie Mitochondriale, Université Bordeaux Segalen, 146 rue Léo Saignat, 33076 Bordeaux, France
| | - Elodie Dumon
- INSERM-U688 Physiopathologie Mitochondriale, Université Bordeaux Segalen, 146 rue Léo Saignat, 33076 Bordeaux, France
| | - Marine Börlin
- INSERM-U688 Physiopathologie Mitochondriale, Université Bordeaux Segalen, 146 rue Léo Saignat, 33076 Bordeaux, France
| | - Barbara Da Costa
- INSERM-U688 Physiopathologie Mitochondriale, Université Bordeaux Segalen, 146 rue Léo Saignat, 33076 Bordeaux, France
| | - Marina Le Guédard
- Laboratoire de Biogenèse Membranaire, CNRS UMR 5200, Université de Bordeaux, INRA Bordeaux Aquitaine, Villenave d'Ornon, France.,LEB Aquitaine Transfert-ADERA, FR-33883 Villenave d'Ornon, Cedex, France
| | - Tanya Stojkovic
- APHP, Centre de Référence des Maladies Neuromusculaires Ile de France Nord Est, G-H Pitié-Salpêtrière, 75013 Paris, France
| | - Natalie Loundon
- Otorhinolaryngologie Pédiatrique, Centre de Référence des Surdités Génétiques, Hôpital Necker, AP-HP, Paris, France
| | - Isabelle Rouillon
- Otorhinolaryngologie Pédiatrique, Centre de Référence des Surdités Génétiques, Hôpital Necker, AP-HP, Paris, France
| | - Yann Nadjar
- Neurologie, GH Pitié Salpêtrière, 75013 Paris, France
| | - Thierry Letellier
- Equipe de Médecine Evolutive, AMIS, UMR 5288 CNRS/Université Paul Sabatier, 31073 Toulouse, France
| | - Laurence Jonard
- Service de Génétique Moléculaire, Hôpital Necker-Enfants Malades, Assistance Publique-Hôpitaux de Paris, 75015 Paris, France
| | - Sandrine Marlin
- Service de Génétique Moléculaire, Hôpital Necker-Enfants Malades, Assistance Publique-Hôpitaux de Paris, 75015 Paris, France.,Centre de Référence des Surdités Génétiques, Service de Génétique Médicale, Hôpital Necker-Enfants Malades, Assistance Publique-Hôpitaux de Paris, 75015 Paris, France.,UMR 1163, Université Paris Descartes, Sorbonne Paris Cité, Institut IMAGINE, 24 Boulevard du Montparnasse, 75015 Paris, France
| | - Christophe Rocher
- INSERM-U688 Physiopathologie Mitochondriale, Université Bordeaux Segalen, 146 rue Léo Saignat, 33076 Bordeaux, France
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11
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Takei S, Homma Y, Matsuyama R, Endo I. Hepatectomy for liver metastasis from rectal cancer in a patient with mitochondrial disease. BMJ Case Rep 2021; 14:14/2/e238653. [PMID: 33547122 PMCID: PMC7871235 DOI: 10.1136/bcr-2020-238653] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
We herein report a woman who was suffering from type 1 diabetes and hearing impairment and whose mother had mitochondrial disease. Abdominal ultrasound identified a hepatic tumour, and a further examination led to the diagnosis of rectal cancer with synchronous multiple liver metastases. A genetic test led to the diagnosis of mitochondrial disease with a mitochondrial gene 3243A>G mutation. After neoadjuvant chemotherapy, we performed hepatectomy and low anterior resection in one stage. Hepatic vascular exclusion was not performed in order to prevent damage to hepatocytes due to liver ischaemia, and Ringer's lactate solution was not used to prevent lactic acidosis. The postoperative course was uneventful. Only one other case involving hepatectomy being performed in a patient with mitochondrial disease has been reported. Considering the extreme rarity of such cases and the importance of perioperative management, we report this case here.
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Affiliation(s)
- Shogo Takei
- Department of Gastroenterological Surgery, Yokohama City University School of Medicine Graduate School of Medicine, Yokohama, Kanagawa, Japan
| | - Yuki Homma
- Department of Gastroenterological Surgery, Yokohama City University School of Medicine Graduate School of Medicine, Yokohama, Kanagawa, Japan
| | - Ryusei Matsuyama
- Department of Gastroenterological Surgery, Yokohama City University School of Medicine Graduate School of Medicine, Yokohama, Kanagawa, Japan
| | - Itaru Endo
- Department of Gastroenterological Surgery, Yokohama City University School of Medicine Graduate School of Medicine, Yokohama, Kanagawa, Japan
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12
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Prakash R, Kannan A. Mitochondrial DNA modification by CRISPR/Cas system: Challenges and future direction. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2021; 178:193-211. [PMID: 33685597 DOI: 10.1016/bs.pmbts.2020.12.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)/Cas (CRISPR associated endonuclease), a hotshot genome editing tool which is originally known to be the form of prokaryotic adaptive immune system against viral infections has gained all the attention of scientific community as a promising genome editing platform. This review encompasses a brief description of mitochondrial disease conditions associated with the alteration in mitochondrial genome (mtDNA) and highlights the key role of the CRISPR/Cas system pertaining to its working mechanism and its involvement in gene-based therapeutics in treating the foresaid mitochondrial diseases. Here, we also extend the perception related to the detailed mechanism of CRISPR/Cas system in mtDNA modification.
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Affiliation(s)
- Rajalakshmi Prakash
- Department of Protein Chemistry and Technology, CSIR-Central Food Technological Research Institute, Mysuru, India; Academy of Scientific and Innovative Research (AcSIR), CSIR-Central Food Technological Research Institute (CSIR-CFTRI) Campus, Mysuru, India
| | - Anbarasu Kannan
- Department of Protein Chemistry and Technology, CSIR-Central Food Technological Research Institute, Mysuru, India; Academy of Scientific and Innovative Research (AcSIR), CSIR-Central Food Technological Research Institute (CSIR-CFTRI) Campus, Mysuru, India.
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13
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Toncheva D, Serbezov D, Karachanak-Yankova S, Nesheva D. Ancient mitochondrial DNA pathogenic variants putatively associated with mitochondrial disease. PLoS One 2020; 15:e0233666. [PMID: 32970680 PMCID: PMC7514063 DOI: 10.1371/journal.pone.0233666] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Accepted: 08/09/2020] [Indexed: 11/18/2022] Open
Abstract
Mitochondrial DNA variants associated with diseases are widely studied in contemporary populations, but their prevalence has not yet been investigated in ancient populations. The publicly available AmtDB database contains 1443 ancient mtDNA Eurasian genomes from different periods. The objective of this study was to use this data to establish the presence of pathogenic mtDNA variants putatively associated with mitochondrial diseases in ancient populations. The clinical significance, pathogenicity prediction and contemporary frequency of mtDNA variants were determined using online platforms. The analyzed ancient mtDNAs contain six variants designated as being "confirmed pathogenic" in modern patients. The oldest of these, m.7510T>C in the MT-TS1 gene, was found in a sample from the Neolithic period, dated 5800-5400 BCE. All six have well established clinical association, and their pathogenic effect is corroborated by very low population frequencies in contemporary populations. Analysis of the geographic location of the ancient samples, contemporary epidemiological trends and probable haplogroup association indicate diverse spatiotemporal dynamics of these variants. The dynamics in the prevalence and distribution is conceivably result of de novo mutations or human migrations and subsequent evolutionary processes. In addition, ten variants designated as possibly or likely pathogenic were found, but the clinical effect of these is not yet well established and further research is warranted. All detected mutations putatively associated with mitochondrial disease in ancient mtDNA samples are in tRNA coding genes. Most of these mutations are in a mt-tRNA type (Model 2) that is characterized by loss of D-loop/T-loop interaction. Exposing pathogenic variants in ancient human populations expands our understanding of their origin and prevalence dynamics.
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Affiliation(s)
- Draga Toncheva
- Department of Medical Genetics, Medical University of Sofia, Bulgarian Academy of Science, Sofia, Bulgaria
- Bulgarian Academy of Sciences–BAS, Sofia, Bulgaria
- * E-mail:
| | - Dimitar Serbezov
- Department of Medical Genetics, Medical University of Sofia, Bulgarian Academy of Science, Sofia, Bulgaria
| | - Sena Karachanak-Yankova
- Department of Medical Genetics, Medical University of Sofia, Bulgarian Academy of Science, Sofia, Bulgaria
- Department of Genetics, Faculty of biology, Sofia University “St. Kliment Ohridski”, Sofia, Bulgaria
| | - Desislava Nesheva
- Department of Medical Genetics, Medical University of Sofia, Bulgarian Academy of Science, Sofia, Bulgaria
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14
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Müller PL, Treis T, Pfau M, Esposti SD, Alsaedi A, Maloca P, Balaskas K, Webster A, Egan C, Tufail A. Progression of Retinopathy Secondary to Maternally Inherited Diabetes and Deafness - Evaluation of Predicting Parameters. Am J Ophthalmol 2020; 213:134-144. [PMID: 31987901 DOI: 10.1016/j.ajo.2020.01.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 12/20/2019] [Accepted: 01/10/2020] [Indexed: 01/01/2023]
Abstract
PURPOSE To investigate the prognostic value of demographic, functional, and imaging parameters on retinal pigment epithelium (RPE) atrophy progression secondary to maternally inherited diabetes and deafness (MIDD) and to evaluate the application of these factors in clinical trial design. DESIGN Retrospective observational case series. METHODS Thirty-five eyes of 20 patients (age range, 24.9-75.9 years) with genetically proven MIDD and demarcated RPE atrophy on serial fundus autofluorescence (AF) images were included. Lesion size and shape-descriptive parameters were longitudinally determined by 2 independent readers. A linear mixed-effect model was used to predict the lesion enlargement rate based on baseline variables. Sample size calculations were performed to model the power in a simulated interventional study. RESULTS The mean follow-up time was 4.27 years. The mean progression rate of RPE atrophy was 2.33 mm2/year, revealing a dependence on baseline lesion size (+0.04 [0.02-0.07] mm2/year/mm2, P < .001), which was absent after square root transformation. The fovea was preserved in the majority of patients during the observation time. In the case of foveal involvement, the loss of visual acuity lagged behind central RPE atrophy in AF images. Sex, age, and number of atrophic foci predicted future progression rates with a cross-validated mean absolute error of 0.13 mm/year and to reduce the required sample size for simulated interventional trials. CONCLUSIONS Progressive RPE atrophy could be traced in all eyes using AF imaging. Shape-descriptive factors and patients' baseline characteristics had significant prognostic value, guiding appropriate subject selection and sample size in future interventional trial design.
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15
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Dolinko AH, Chwa M, Atilano SR, Kenney MC. African and Asian Mitochondrial DNA Haplogroups Confer Resistance Against Diabetic Stresses on Retinal Pigment Epithelial Cybrid Cells In Vitro. Mol Neurobiol 2020; 57:1636-1655. [PMID: 31811564 PMCID: PMC7123578 DOI: 10.1007/s12035-019-01834-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 11/12/2019] [Indexed: 01/09/2023]
Abstract
Diabetic retinopathy (DR) is the most common cause of blindness for individuals under the age of 65. This loss of vision can be due to ischemia, neovascularization, and/or diabetic macular edema, which are caused by breakdown of the blood-retina barrier at the level of the retinal pigment epithelium (RPE) and inner retinal vasculature. The prevalence of diabetes and its complications differ between Caucasian-Americans and certain minority populations, such as African-Americans and Asian-Americans. Individuals can be classified by their mitochondrial haplogroups, which are collections of single nucleotide polymorphisms (SNPs) in mitochondrial DNA (mtDNA) representing ancient geographic origins of populations. In this study, we compared the responses of diabetic human RPE cybrids, cell lines containing identical nuclei but mitochondria from either European (maternal European) or maternal African or Asian individuals, to hypoxia and high glucose levels. The African and Asian diabetic ([Afr+Asi]/DM) cybrids showed (1) resistance to both hyperglycemic and hypoxic stresses; (2) downregulation of pro-apoptotic indicator BAX; (3) upregulation of DNA methylation genes, such as DNMT3A and DNMT3B; and (4) resistance to DNA demethylation by the methylation inhibitor 5-Aza-2'-deoxycytidine (5-Aza-dC) compared to European diabetic (Euro/DM) cybrids. Our findings suggest that mitochondria from African and Asian diabetic subjects possess a "metabolic memory" that confers resistance against hyperglycemia, hypoxia, and demethylation, and that this "metabolic memory" can be transferred into the RPE cybrid cell lines in vitro.
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Affiliation(s)
- Andrew H Dolinko
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, CA, 92697, USA
- Department of Ophthalmology Research, Gavin Herbert Eye Institute, University of California Irvine, Hewitt Hall, Room 2028, 843 Health Science Road, Irvine, CA, 92697, USA
| | - Marilyn Chwa
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, CA, 92697, USA
| | - Shari R Atilano
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, CA, 92697, USA
| | - M Cristina Kenney
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, CA, 92697, USA.
- Department of Ophthalmology Research, Gavin Herbert Eye Institute, University of California Irvine, Hewitt Hall, Room 2028, 843 Health Science Road, Irvine, CA, 92697, USA.
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16
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Hougaard DD, Hestoy DH, Hojland AT, Gailhede M, Petersen MB. Audiological and Vestibular Findings in Subjects with MELAS Syndrome. J Int Adv Otol 2020; 15:296-303. [PMID: 31347509 DOI: 10.5152/iao.2019.5913] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVES The mitochondrial DNA (mtDNA) point mutation m.3243A>G is known to express the following two syndromes among others: maternally inherited diabetes and deafness (MIDD) and mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). Sensorineural hearing loss (SNHL) is the most frequent symptom in individuals harboring the m.3243A>G mutation. However, dysfunction of the vestibular organs has been scarcely examined. Therefore, the present study aimed to study the impact of the m.3243A>G mutation on the inner ear. MATERIALS AND METHODS A total of 8 subjects harboring the blood-verified m.3243A>G mutation underwent thorough audiological and vestibular examinations, including tone and speech audiometry, video head impulse test (vHIT), ocular and cervical vestibular-evoked myogenic potential (oVEMP and cVEMP), and full otoneurological examination. The subjects also answered a Dizziness Handicap Inventory (DHI) questionnaire. RESULTS SNHL was identified in all the 8 subjects, with a mean pure-tone average-4 (PTA-4) of 59 dB. Speech discrimination score (n=7) ranged from 24% to 100% (mean 74%), and vHIT (n=42) detected pathology in nine lateral semicircular canals (SCCs), five posterior SCCs, and one anterior SCC, whereas three measurements were inconclusive. All oVEMPs (n=14 ears) were absent, nine cVEMPs were absent, and two were inconclusive. Based on the DHI scores, 6 subjects reported none to mild dizziness, 1 reported moderate, and 1 reported severe dizziness. CONCLUSION Our study population had pathological findings from every audiological and vestibular end organs. The results indicated that the pathological findings originated from within the end organs themselves and not within the superior and inferior vestibular or cochlear nerve.
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Affiliation(s)
- Dan Dupont Hougaard
- Department of Otolaryngology, Head - Neck Surgery and Audiology, Aalborg University Hospital, Aalborg, Denmark;Department of Clinical Medicine, Aalborg University School of Medicine, Denmark
| | | | - Allan Thomas Hojland
- Department of Clinical Medicine, Aalborg University School of Medicine, Denmark;Department of Clinical Genetics, Aalborg University Hospital, Denmark
| | - Michael Gailhede
- Department of Otolaryngology, Head - Neck Surgery and Audiology, Aalborg University Hospital, Aalborg, Denmark;Department of Clinical Medicine, Aalborg University School of Medicine, Denmark
| | - Michael Bjorn Petersen
- Department of Clinical Medicine, Aalborg University School of Medicine, Denmark;Research and Knowledge Center in Sensory Genetics, Aalborg University Hospital, Denmark
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Boggan RM, Lim A, Taylor RW, McFarland R, Pickett SJ. Resolving complexity in mitochondrial disease: Towards precision medicine. Mol Genet Metab 2019; 128:19-29. [PMID: 31648942 DOI: 10.1016/j.ymgme.2019.09.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 09/12/2019] [Accepted: 09/12/2019] [Indexed: 12/12/2022]
Abstract
Mitochondrial diseases, caused by mutations in either the nuclear or mitochondrial genomes (mtDNA), are the most common form of inherited neurometabolic disorders. They are remarkably heterogeneous, both in their clinical presentation and genetic etiology, presenting challenges for diagnosis, clinical management and elucidation of molecular mechanism. The multifaceted nature of these diseases, compounded by the unique characteristics of mitochondrial genetics, cement their space in the field of complex disease. In this review we examine the m.3243A>G variant, one of the most prevalent mitochondrial DNA mutations, using it as an exemplar to demonstrate the challenges presented by these complex disorders. Disease caused by m.3243A>G is one of the most phenotypically diverse of all mitochondrial diseases; we outline known causes of this heterogeneity including mtDNA heteroplasmy, mtDNA copy number and nuclear genetic factors. We consider the impact that this has in the clinic, discussing the personalized management of common manifestations attributed to this pathogenic mtDNA variant, including hearing impairment, diabetes mellitus, myopathy, cardiac disease, stroke-like episodes and gastrointestinal disturbances. Future research into this complex disorder must account for this heterogeneity, benefitting from the use of large patient cohorts to build upon current clinical expertise. Through multi-disciplinary collaboration, the complexities of this mitochondrial disease can be addressed with the variety of diagnostic, prognostic, and treatment approaches that are moulded to best fit the needs of each individual patient.
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Affiliation(s)
- Róisín M Boggan
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Albert Lim
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Robert McFarland
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
| | - Sarah J Pickett
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
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18
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Castora FJ. Mitochondrial function and abnormalities implicated in the pathogenesis of ASD. Prog Neuropsychopharmacol Biol Psychiatry 2019; 92:83-108. [PMID: 30599156 DOI: 10.1016/j.pnpbp.2018.12.015] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 12/20/2018] [Accepted: 12/24/2018] [Indexed: 12/18/2022]
Abstract
Mitochondria are the powerhouse that generate over 90% of the ATP produced in cells. In addition to its role in energy production, the mitochondrion also plays a major role in carbohydrate, fatty acid, amino acid and nucleotide metabolism, programmed cell death (apoptosis), generation of and protection against reactive oxygen species (ROS), immune response, regulation of intracellular calcium ion levels and even maintenance of gut microbiota. With its essential role in bio-energetic as well as non-energetic biological processes, it is not surprising that proper cellular, tissue and organ function is dependent upon proper mitochondrial function. Accordingly, mitochondrial dysfunction has been shown to be directly linked to a variety of medical disorders, particularly neuromuscular disorders and increasing evidence has linked mitochondrial dysfunction to neurodegenerative and neurodevelopmental disorders such as Alzheimer's Disease (AD), Parkinson's Disease (PD), Rett Syndrome (RS) and Autism Spectrum Disorders (ASD). Over the last 40 years there has been a dramatic increase in the diagnosis of ASD and, more recently, an increasing body of evidence indicates that mitochondrial dysfunction plays an important role in ASD development. In this review, the latest evidence linking mitochondrial dysfunction and abnormalities in mitochondrial DNA (mtDNA) to the pathogenesis of autism will be presented. This review will also summarize the results of several recent `approaches used for improving mitochondrial function that may lead to new therapeutic approaches to managing and/or treating ASD.
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Affiliation(s)
- Frank J Castora
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, VA, USA; Department of Neurology, Eastern Virginia Medical School, Norfolk, VA, USA.
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19
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Zhou Z, Sun B, Huang S, Jia W, Yu D. The tRNA-associated dysregulation in diabetes mellitus. Metabolism 2019; 94:9-17. [PMID: 30711570 DOI: 10.1016/j.metabol.2019.01.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 01/26/2019] [Accepted: 01/30/2019] [Indexed: 12/26/2022]
Abstract
Diabetes mellitus (DM) is a complex endocrine and metabolic disorder for human health and well-being. Deregulated glucose and lipid metabolism are the primary underlying manifestations associated with this disease. Transfer RNAs (tRNAs) are considered to mainly participate in protein translation and may contribute to complex human pathologies. Although the molecular mechanisms remain, for the most part, unknown, accumulating evidence indicates that tRNAs play a vital role in the pathogenesis of DM. This paper reviews different aspects of tRNA-associated dysregulation in DM, such as tRNA mutations, tRNA modifications, tRNA aminoacylation and tRNA derivatives, aiming at a better understanding of the pathogenesis of DM and providing new ideas for the personalized treatment of this metabolism-associated disease.
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Affiliation(s)
- Zheng Zhou
- Department of Chinese Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450000, China
| | - Bao Sun
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410000, China; Hunan Key Laboratory of Pharmacogenetics, Institute of Clinical Pharmacology, Central South University, Changsha 410000, China
| | - Shiqiong Huang
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410000, China; Hunan Key Laboratory of Pharmacogenetics, Institute of Clinical Pharmacology, Central South University, Changsha 410000, China
| | - Wenrui Jia
- Department of Chinese Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450000, China
| | - Dongsheng Yu
- Department of Chinese Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450000, China.
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20
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Chen Z, Zhang F, Xu H. Human mitochondrial DNA diseases and Drosophila models. J Genet Genomics 2019; 46:201-212. [DOI: 10.1016/j.jgg.2019.03.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 03/05/2019] [Accepted: 03/25/2019] [Indexed: 01/06/2023]
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Pei L, Wallace DC. Mitochondrial Etiology of Neuropsychiatric Disorders. Biol Psychiatry 2018; 83:722-730. [PMID: 29290371 PMCID: PMC5891364 DOI: 10.1016/j.biopsych.2017.11.018] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 10/31/2017] [Accepted: 11/02/2017] [Indexed: 12/30/2022]
Abstract
The brain has the highest mitochondrial energy demand of any organ. Therefore, subtle changes in mitochondrial energy production will preferentially affect the brain. Considerable biochemical evidence has accumulated revealing mitochondrial defects associated with neuropsychiatric diseases. Moreover, the mitochondrial genome encompasses over a thousand nuclear DNA genes plus hundreds to thousands of copies of the maternally inherited mitochondrial DNA (mtDNA). Therefore, partial defects in either the nuclear DNA or mtDNA genes or combinations of the two can be sufficient to cause neuropsychiatric disorders. Inherited and acquired mtDNA mutations have recently been associated with autism spectrum disorder, which parallels previous evidence of mtDNA variation in other neurological diseases. Therefore, mitochondrial dysfunction may be central to the etiology of a wide spectrum of neurological diseases. The mitochondria and the nucleus communicate to coordinate energy production and utilization, providing the potential for therapeutics by manipulating nuclear regulation of mitochondrial gene expression.
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Tarnopolsky MA, Sundaram ANE, Provias J, Brady L, Sadikovic B. CPEO - Like mitochondrial myopathy associated with m.8340G>A mutation. Mitochondrion 2018; 46:69-72. [PMID: 29501485 DOI: 10.1016/j.mito.2018.02.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 02/22/2018] [Accepted: 02/23/2018] [Indexed: 11/19/2022]
Abstract
Two patients with an m.8340G>A mitochondrial DNA variant have been reported with one patient showing ptosis, ophthalmoparesis and myopathy at 53% heteroplasmy and another with pigmentary retinopathy, cataracts and sensory neural deafness and slightly higher heteroplasmy (65%). Here we report that higher muscle mutant heteroplasmy (93%) for m.8340G>A is associated with ptosis, ophthalmoparesis and mitochondrial myopathy, thus confirming the initial phenotypic association and showing that heteroplasmy per se does not explain the phenotypic spectrum of disease associated with the m.8340G>A mutation.
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Affiliation(s)
- Mark A Tarnopolsky
- Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada.
| | - Arun N E Sundaram
- Department of Ophthalmology and Vision Sciences, Sunnybrook Health Sciences Center, University of Toronto, Toronto, Ontario, Canada
| | - John Provias
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Lauren Brady
- Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada
| | - Bekim Sadikovic
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, Children's Health Research Institute, London, Ontario, Canada
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Alexandar SP, Dhinakaran I, Ravi V, Parthasarathy N, Ganesan S, Bhaskaran M, Arun Kumar GP. Meta-Analysis of Association of Mitochondrial DNA Mutations with Type 2 Diabetes and Gestational Diabetes Mellitus. INT J HUM GENET 2018. [DOI: 10.1080/09723757.2018.1430110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Soundarya Priya Alexandar
- Human Genomics Laboratory, School of Chemical & Biotechnology, SASTRA University Thanjavur, Thanjavur 613 401, Tamil Nadu, India
| | - Indhumathi Dhinakaran
- Human Genomics Laboratory, School of Chemical & Biotechnology, SASTRA University Thanjavur, Thanjavur 613 401, Tamil Nadu, India
| | - Vidhya Ravi
- K.A.P. Viswanatham Govt. Medical College, Trichy, 620 001, Tamil Nadu, India
| | - Nandhini Parthasarathy
- Human Genomics Laboratory, School of Chemical & Biotechnology, SASTRA University Thanjavur, Thanjavur 613 401, Tamil Nadu, India
| | - Somasundari Ganesan
- Human Genomics Laboratory, School of Chemical & Biotechnology, SASTRA University Thanjavur, Thanjavur 613 401, Tamil Nadu, India
| | - Muthumeenakshi Bhaskaran
- Human Genomics Laboratory, School of Chemical & Biotechnology, SASTRA University Thanjavur, Thanjavur 613 401, Tamil Nadu, India
| | - Ganesh Prasad Arun Kumar
- Human Genomics Laboratory, School of Chemical & Biotechnology, SASTRA University Thanjavur, Thanjavur 613 401, Tamil Nadu, India
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Mitochondrial energy deficiency leads to hyperproliferation of skeletal muscle mitochondria and enhanced insulin sensitivity. Proc Natl Acad Sci U S A 2017; 114:2705-2710. [PMID: 28223503 DOI: 10.1073/pnas.1700997114] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Diabetes is associated with impaired glucose metabolism in the presence of excess insulin. Glucose and fatty acids provide reducing equivalents to mitochondria to generate energy, and studies have reported mitochondrial dysfunction in type II diabetes patients. If mitochondrial dysfunction can cause diabetes, then we hypothesized that increased mitochondrial metabolism should render animals resistant to diabetes. This was confirmed in mice in which the heart-muscle-brain adenine nucleotide translocator isoform 1 (ANT1) was inactivated. ANT1-deficient animals are insulin-hypersensitive, glucose-tolerant, and resistant to high fat diet (HFD)-induced toxicity. In ANT1-deficient skeletal muscle, mitochondrial gene expression is induced in association with the hyperproliferation of mitochondria. The ANT1-deficient muscle mitochondria produce excess reactive oxygen species (ROS) and are partially uncoupled. Hence, the muscle respiration under nonphosphorylating conditions is increased. Muscle transcriptome analysis revealed the induction of mitochondrial biogenesis, down-regulation of diabetes-related genes, and increased expression of the genes encoding the myokines FGF21 and GDF15. However, FGF21 was not elevated in serum, and FGF21 and UCP1 mRNAs were not induced in liver or brown adipose tissue (BAT). Hence, increased oxidation of dietary-reducing equivalents by elevated muscle mitochondrial respiration appears to be the mechanism by which ANT1-deficient mice prevent diabetes, demonstrating that the rate of mitochondrial oxidation of calories is important in the etiology of metabolic disease.
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25
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Dvorakova V, Kolarova H, Magner M, Tesarova M, Hansikova H, Zeman J, Honzik T. The phenotypic spectrum of fifty Czech m.3243A>G carriers. Mol Genet Metab 2016; 118:288-95. [PMID: 27296531 DOI: 10.1016/j.ymgme.2016.06.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 06/04/2016] [Accepted: 06/05/2016] [Indexed: 01/19/2023]
Abstract
BACKGROUND Mitochondrial myopathy, Encephalopathy, Lactic Acidosis and Stroke-like episodes syndrome (MELAS) is a common mitochondrial disorder with varying multisystemic clinical manifestation. We present a comprehensive clinical picture of 50 Czech m.3243A>G carriers with emphasis on the sequence of symptoms in symptomatic patients. RESULTS Symptoms developed in 33 patients (66%) and 17 carriers remained unaffected (34%). The age of onset varied from 1month to 47years of age, with juvenile presentation occurring in 53% of patients. Myopathy was the most common presenting symptom (18%), followed by CPEO/ptosis and hearing loss, with the latter also being the most common second symptom. Stroke-like episodes (SLE) occurred in fourteen patients, although never as a first symptom, and were frequently preceded by migraines (58%). Rhabdomyolysis developed in two patients. The second symptom appeared 5.0±8.3years (range 0-28years) after the first, and the interval between the second and third symptom was 2.0±6.0years (range 0-21years). Four of our patients remained monosymptomatic up to 12years of follow-up. The sequence of symptoms according to their time of manifestation was migraines, myopathy, seizures, CPEO/ptosis, SLE, hearing loss, and diabetes mellitus. The average age at death was 32.4±17.7years (range 9-60years) in the juvenile form and 44.0±12.7years (range 35-53years) in the adult form. Some patients with SLE harboured very low heteroplasmy levels in various tissues. No threshold for any organ dysfunction could be determined based on these levels. CONCLUSIONS Sufficient knowledge of the timeline of the natural course of MELAS syndrome may improve the prediction and management of symptoms in patients with this mitochondrial disease.
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Affiliation(s)
- V Dvorakova
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague, General University Hospital in Prague, Czech Republic
| | - H Kolarova
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague, General University Hospital in Prague, Czech Republic
| | - M Magner
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague, General University Hospital in Prague, Czech Republic
| | - M Tesarova
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague, General University Hospital in Prague, Czech Republic
| | - H Hansikova
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague, General University Hospital in Prague, Czech Republic
| | - J Zeman
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague, General University Hospital in Prague, Czech Republic
| | - T Honzik
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague, General University Hospital in Prague, Czech Republic.
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27
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Quispe-Tintaya W, White RR, Popov VN, Vijg J, Maslov AY. Rapid mitochondrial DNA isolation method for direct sequencing. Methods Mol Biol 2015; 1264:89-95. [PMID: 25631006 DOI: 10.1007/978-1-4939-2257-4_9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Standard methods for mitochondrial DNA (mtDNA) extraction do not provide the level of enrichment for mtDNA sufficient for direct sequencing and must be followed by long-range-PCR amplification, which can bias the sequence results. Here, we describe a reliable method for the preparation of mtDNA-enriched samples from eukaryotic cells ready for direct sequencing. This protocol utilizes a conventional miniprep kit, in conjunction with a paramagnetic bead-based purification step.
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Affiliation(s)
- Wilber Quispe-Tintaya
- Department of Genetics, Albert Einstein College of Medicine, New York, NY, 10461, USA
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28
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Abstract
The oversupply of calories and sedentary lifestyle has resulted in a rapid increase of diabetes prevalence worldwide. During the past two decades, lines of evidence suggest that mitochondrial dysfunction plays a key role in the pathophysiology of diabetes. Mitochondria are vital to most of the eukaryotic cells as they provide energy in the form of adenosine triphosphate by oxidative phosphorylation. In addition, mitochondrial function is an integral part of glucose-stimulated insulin secretion in pancreatic β-cells. In the present article, we will briefly review the major functions of mitochondria in regard to energy metabolism, and discuss the genetic and environmental factors causing mitochondrial dysfunction in diabetes. In addition, the pathophysiological role of mitochondrial dysfunction in insulin resistance and β-cell dysfunction are discussed. We argue that mitochondrial dysfunction could be the central defect causing the abnormal glucose metabolism in the diabetic state. A deeper understanding of the role of mitochondria in diabetes will provide us with novel insights in the pathophysiology of diabetes. (J Diabetes Invest, doi: 10.1111/j.2040-1124.2010.00047.x, 2010).
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Affiliation(s)
| | - Kyong Soo Park
- Departments of Internal Medicine ; Molecular Medicine and Biopharmaceutical Sciences, Seoul National University College of Medicine
| | - Ki-Up Lee
- Department of Internal Medicine, University of Ulsan College of Medicine
| | - Hong Kyu Lee
- Department of Internal Medicine, Eulji University College of Medicine, Seoul, Korea
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29
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Adeva-Andany M, López-Ojén M, Funcasta-Calderón R, Ameneiros-Rodríguez E, Donapetry-García C, Vila-Altesor M, Rodríguez-Seijas J. Comprehensive review on lactate metabolism in human health. Mitochondrion 2014; 17:76-100. [PMID: 24929216 DOI: 10.1016/j.mito.2014.05.007] [Citation(s) in RCA: 359] [Impact Index Per Article: 35.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 03/19/2014] [Accepted: 05/05/2014] [Indexed: 02/07/2023]
Abstract
Metabolic pathways involved in lactate metabolism are important to understand the physiological response to exercise and the pathogenesis of prevalent diseases such as diabetes and cancer. Monocarboxylate transporters are being investigated as potential targets for diagnosis and therapy of these and other disorders. Glucose and alanine produce pyruvate which is reduced to lactate by lactate dehydrogenase in the cytoplasm without oxygen consumption. Lactate removal takes place via its oxidation to pyruvate by lactate dehydrogenase. Pyruvate may be either oxidized to carbon dioxide producing energy or transformed into glucose. Pyruvate oxidation requires oxygen supply and the cooperation of pyruvate dehydrogenase, the tricarboxylic acid cycle, and the mitochondrial respiratory chain. Enzymes of the gluconeogenesis pathway sequentially convert pyruvate into glucose. Congenital or acquired deficiency on gluconeogenesis or pyruvate oxidation, including tissue hypoxia, may induce lactate accumulation. Both obese individuals and patients with diabetes show elevated plasma lactate concentration compared to healthy subjects, but there is no conclusive evidence of hyperlactatemia causing insulin resistance. Available evidence suggests an association between defective mitochondrial oxidative capacity in the pancreatic β-cells and diminished insulin secretion that may trigger the development of diabetes in patients already affected with insulin resistance. Several mutations in the mitochondrial DNA are associated with diabetes mellitus, although the pathogenesis remains unsettled. Mitochondrial DNA mutations have been detected in a number of human cancers. d-lactate is a lactate enantiomer normally formed during glycolysis. Excess d-lactate is generated in diabetes, particularly during diabetic ketoacidosis. d-lactic acidosis is typically associated with small bowel resection.
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Affiliation(s)
- M Adeva-Andany
- Nephrology Division, Hospital General Juan Cardona, Ave. Pardo Bazán, s/n, 15406 Ferrol, La Coruña, Spain.
| | - M López-Ojén
- Internal Medicine Division, Policlínica Assistens, c/Federico García, 4-planta baja, 15009 La Coruña, Spain
| | - R Funcasta-Calderón
- Nephrology Division, Hospital General Juan Cardona, Ave. Pardo Bazán, s/n, 15406 Ferrol, La Coruña, Spain
| | - E Ameneiros-Rodríguez
- Nephrology Division, Hospital General Juan Cardona, Ave. Pardo Bazán, s/n, 15406 Ferrol, La Coruña, Spain
| | - C Donapetry-García
- Nephrology Division, Hospital General Juan Cardona, Ave. Pardo Bazán, s/n, 15406 Ferrol, La Coruña, Spain
| | - M Vila-Altesor
- Nephrology Division, Hospital General Juan Cardona, Ave. Pardo Bazán, s/n, 15406 Ferrol, La Coruña, Spain
| | - J Rodríguez-Seijas
- Nephrology Division, Hospital General Juan Cardona, Ave. Pardo Bazán, s/n, 15406 Ferrol, La Coruña, Spain
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Stroh M, Swerdlow RH, Zhu H. Common defects of mitochondria and iron in neurodegeneration and diabetes (MIND): a paradigm worth exploring. Biochem Pharmacol 2014; 88:573-83. [PMID: 24361914 PMCID: PMC3972369 DOI: 10.1016/j.bcp.2013.11.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 11/25/2013] [Accepted: 11/25/2013] [Indexed: 12/19/2022]
Abstract
A popular, if not centric, approach to the study of an event is to first consider that of the simplest cause. When dissecting the underlying mechanisms governing idiopathic diseases, this generally takes the form of an ab initio genetic approach. To date, this genetic 'smoking gun' has remained elusive in diabetes mellitus and for many affected by neurodegenerative diseases. With no single gene, or even subset of genes, conclusively causative in all cases, other approaches to the etiology and treatment of these diseases seem reasonable, including the correlation of a systems' predisposed sensitivity to particular influence. In the cases of diabetes mellitus and neurodegenerative diseases, overlapping themes of mitochondrial influence or dysfunction and iron dyshomeostasis are apparent and relatively consistent. This mini-review discusses the influence of mitochondrial function and iron homeostasis on diabetes mellitus and neurodegenerative disease, namely Alzheimer's disease. Also discussed is the incidence of diabetes accompanied by neuropathy and neurodegeneration along with neurodegenerative disorders prone to development of diabetes. Mouse models containing multiple facets of this overlap are also described alongside current molecular trends attributed to both diseases. As a way of approaching the idiopathic and complex nature of these diseases we are proposing the consideration of a MIND (mitochondria, iron, neurodegeneration, and diabetes) paradigm in which systemic metabolic influence, iron homeostasis, and respective genetic backgrounds play a central role in the development of disease.
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Affiliation(s)
- Matthew Stroh
- Neuroscience Graduate Program, University of Kansas Medical Center, Kansas City, KS 66160, USA; Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Russell H Swerdlow
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS 66160, USA; Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
| | - Hao Zhu
- Neuroscience Graduate Program, University of Kansas Medical Center, Kansas City, KS 66160, USA; Department of Clinical Laboratory Sciences, University of Kansas Medical Center, Kansas City, KS 66160, USA; Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
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31
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Fast mitochondrial DNA isolation from mammalian cells for next-generation sequencing. Biotechniques 2014; 55:133-6. [PMID: 24003945 DOI: 10.2144/000114077] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 07/30/2013] [Indexed: 11/23/2022] Open
Abstract
Standard methods for mitochondrial DNA (mtDNA) extraction do not provide the level of enrichment for mtDNA sufficient for direct sequencing and must be followed by long-range-PCR amplification, which can bias the sequencing results. Here, we describe a fast, cost-effective, and reliable method for preparation of mtDNA enriched samples from eukaryotic cells ready for direct sequencing. Our protocol utilizes a conventional miniprep kit, paramagnetic bead-based purification, and an optional, limited PCR amplification of mtDNA. The first two steps alone provide more than 2000-fold enrichment for mtDNA when compared with total cellular DNA (~200-fold in comparison with current commercially available kits) as demonstrated by real-time PCR. The percentage of sequencing reads aligned to mtDNA was about 22% for non-amplified samples and greater than 99% for samples subjected to 10 cycles of long-range-PCR with mtDNA specific primers.
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32
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Veerappa AM, N MM, Vishweswaraiah S, Lingaiah K, Suresh RV, Nachappa SA, Prashali N, Yadav SN, Srikanta MA, Manjegowda DS, Seshachalam KB, Ramachandra NB. Copy number variations burden on miRNA genes reveals layers of complexities involved in the regulation of pathways and phenotypic expression. PLoS One 2014; 9:e90391. [PMID: 24587348 PMCID: PMC3938728 DOI: 10.1371/journal.pone.0090391] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 01/28/2014] [Indexed: 12/21/2022] Open
Abstract
MicroRNAs are involved in post-transcriptional down-regulation of gene expression. Variations in miRNA genes can severely affect downstream-regulated genes and their pathways. However, population-specific burden of CNVs on miRNA genes and the complexities created towards the phenotype is not known. From a total of 44109 CNVs investigated from 1715 individuals across 12 populations using high-throughput arrays, 4007 miRNA-CNVs (∼ 9%) consisting 6542 (∼ 5%) miRNA genes with a total of 333 (∼ 5%) singleton miRNA genes were identified. We found miRNA-CNVs across the genomes of individuals showing multiple hits in many targets, co-regulated under the same pathway. This study proposes four mechanisms unraveling the many complexities in miRNA genes, targets and co-regulated miRNA genes towards establishment of phenotypic diversity.
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Affiliation(s)
- Avinash M. Veerappa
- Genetics and Genomics Lab, Department of Studies in Zoology, University of Mysore, Manasagangotri, Mysore, Karnataka, India
| | - Megha Murthy N
- Genetics and Genomics Lab, Department of Studies in Zoology, University of Mysore, Manasagangotri, Mysore, Karnataka, India
| | - Sangeetha Vishweswaraiah
- Genetics and Genomics Lab, Department of Studies in Zoology, University of Mysore, Manasagangotri, Mysore, Karnataka, India
| | - Kusuma Lingaiah
- Genetics and Genomics Lab, Department of Studies in Zoology, University of Mysore, Manasagangotri, Mysore, Karnataka, India
| | - Raviraj V. Suresh
- Genetics and Genomics Lab, Department of Studies in Zoology, University of Mysore, Manasagangotri, Mysore, Karnataka, India
| | - Somanna Ajjamada Nachappa
- Genetics and Genomics Lab, Department of Studies in Zoology, University of Mysore, Manasagangotri, Mysore, Karnataka, India
| | - Nelchi Prashali
- Genetics and Genomics Lab, Department of Studies in Zoology, University of Mysore, Manasagangotri, Mysore, Karnataka, India
| | - Sangeetha Nuggehalli Yadav
- Genetics and Genomics Lab, Department of Studies in Zoology, University of Mysore, Manasagangotri, Mysore, Karnataka, India
| | - Manjula Arsikere Srikanta
- Genetics and Genomics Lab, Department of Studies in Zoology, University of Mysore, Manasagangotri, Mysore, Karnataka, India
| | - Dinesh S. Manjegowda
- Department of Anatomy, Yenepoya Medical College, Yenepoya University, Mangalore, Karnataka, India
- Nitte University Centre for Science Education & Research, K S Hegde Medical Academy, Nitte University, Deralakatte, Mangalore, Karnataka, India
| | | | - Nallur B. Ramachandra
- Genetics and Genomics Lab, Department of Studies in Zoology, University of Mysore, Manasagangotri, Mysore, Karnataka, India
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McInnes J. Mitochondrial-associated metabolic disorders: foundations, pathologies and recent progress. Nutr Metab (Lond) 2013; 10:63. [PMID: 24499129 PMCID: PMC3853754 DOI: 10.1186/1743-7075-10-63] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 10/08/2013] [Indexed: 01/06/2023] Open
Abstract
Research in the last decade has revolutionized the way in which we view mitochondria. Mitochondria are no longer viewed solely as cellular powerhouses; rather, mitochondria are now understood to be vibrant, mobile structures, constantly undergoing fusion and fission, and engaging in intimate interactions with other cellular compartments and structures. Findings have implicated mitochondria in a wide variety of cellular processes and molecular interactions, such as calcium buffering, lipid flux, and intracellular signaling. As such, it does not come as a surprise that an increasing number of human pathologies have been associated with functional defects in mitochondria. The difficulty in understanding and treating human pathologies caused by mitochondrial dysfunction arises from the complex relationships between mitochondria and other cellular processes, as well as the genetic background of such diseases. This review attempts to provide a summary of the background knowledge and recent developments in mitochondrial processes relating to mitochondrial-associated metabolic diseases arising from defects or deficiencies in mitochondrial function, as well as insights into current and future avenues for investigation.
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Affiliation(s)
- Joseph McInnes
- School of Engineering and Science, Research Center MOLIFE - Molecular Life Science, Jacobs University Bremen, Campus Ring 1, Research II, Room 120, Bremen D-28759, Germany.
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Martikainen MH, Rönnemaa T, Majamaa K. Prevalence of mitochondrial diabetes in southwestern Finland: a molecular epidemiological study. Acta Diabetol 2013; 50:737-41. [PMID: 22492248 DOI: 10.1007/s00592-012-0393-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Accepted: 03/30/2012] [Indexed: 11/29/2022]
Abstract
Mitochondrial diabetes and deafness (MIDD) is a subtype of diabetes mellitus (DM) that most commonly results from the m.3243A > G mutation in mitochondrial DNA (mtDNA). Sensorineural hearing loss is a typical accompanying feature. Previous studies have suggested a prevalence of ~1-1.5 % for MIDD. We studied the molecular epidemiology of MIDD among young (aged 18-45 years) adults in a defined population in southwestern Finland. Of the identified cohort of 1,532 patients with DM, we received blood samples of 299 patients and analyzed them for the m.3243A > G mutation and for mtDNA haplogroups. We found three DM patients (1.0 %) with the m.3243A > G mutation. All the three patients with DM and m.3243A > G also had severe hearing impairment that required use of hearing aid. MtDNA haplogroup U was more prevalent among patients with maternal family history of DM. We conclude that among young adults, ~1 % of all DM is associated with the m.3243A > G mutation. We suggest that all patients with both DM and hearing impairment, at least in this age group, should undergo investigation for this mutation. Furthermore, our results suggest that mtDNA haplogroup U is associated with maternal family history of DM.
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Affiliation(s)
- Mika H Martikainen
- Department of Neurology, University of Turku and Turku University Hospital, Turku, Finland,
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Moreno-Loshuertos R, Pérez-Martos A, Fernández-Silva P, Enríquez JA. Length variation in the mouse mitochondrial tRNA(Arg) DHU loop size promotes oxidative phosphorylation functional differences. FEBS J 2013; 280:4983-98. [PMID: 23910637 DOI: 10.1111/febs.12466] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 06/07/2013] [Accepted: 07/22/2013] [Indexed: 01/24/2023]
Abstract
The efficiency of the cellular oxidative phosphorylation system was recently shown to be modulated by common mitochondrial tRNA(A) (rg) haplotypes. The molecular mechanism by which some mt-Tr haplotypes induce these functional differences remains undetermined. Common polymorphisms in mouse mt-Tr genes affect the size of the dihydrouridine loop in the mature tRNA, producing loops of between five and seven nucleotides, the largest being a rare variant among mammals. Here, we analyzed a new mt-Tr variant identified in C3H mice, and found that it is mitochondrial tRNA loop size, but not the specific sequence, that is responsible for the observed differences in cellular respiration. We further found that the sensitivity of mitochondrial protein synthesis to specific inhibitors is dependent on the mt-Tr gene haplotype, and confirmed that the differences in oxidative phosphorylation performance are masked by a reactive oxygen species-induced compensatory increase in mitochondrial biogenesis.
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Abstract
Mitochondrial diseases are a diverse group of inherited and acquired disorders that result in inadequate energy production. They can be caused by inheritable genetic mutations, acquired somatic mutations, and exposure to toxins (including some prescription medications). Normal mitochondrial physiology is responsible, in part, for the aging process itself, as free radical production within the mitochondria results in a lifetime burden of oxidative damage to DNA, especially the mitochondrial DNA that, in turn, replicate the mutational burden in future copies of itself, and lipid membranes. Primary mitochondrial diseases are those caused by mutations in genes that encode for mitochondrial structural and enzymatic proteins, and those proteins required for mitochondrial assembly and maintenance. A number of common adult maladies are associated with defective mitochondrial energy production and function, including diabetes, obesity, hyperthyroidism, hypothyroidism, and hyperlipidemia. Mitochondrial dysfunction has been demonstrated in many neurodegenerative disorders, including Alzheimer's disease, Parkinson disease, amyotrophic lateral sclerosis, and some cancers. Polymorphisms in mitochondrial DNA have been linked to disease susceptibility, including death from sepsis and survival after head injury. There is considerable overlap in symptoms caused by primary mitochondrial diseases and those illnesses that affect mitochondrial function, but are not caused by primary mutations, as well as disorders that mimic mitochondrial diseases, but are caused by other identified mutations. Evaluation of these disorders is complex, expensive, and not without false-negative and false-positive results that can mislead the physician. Most of the common heritable mitochondrial disorders have been well-described in the literature, but can be overlooked by many clinicians if they are uneducated about these disorders. In general, the evaluation of the classic mitochondrial disorders has become straightforward if the clinician recognized the phenotype and orders appropriate confirmatory testing. However, the majority of patients referred for a mitochondrial evaluation do not have a clear presentation that allows for rapid identification and testing. This article provides introductory comments on mitochondrial structure, physiology, and genetics, but will focus on the presentation and evaluation of adults with mitochondrial symptoms, but who may not have a primary mitochondrial disease.
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Affiliation(s)
- Bruce H Cohen
- NeuroDevelopmental Science Center, Children's Hospital Medical Center of Akron, 215 West Bowery Street, Suite 4400, Akron, OH 44308, USA.
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Soini HK, Moilanen JS, Finnila S, Majamaa K. Mitochondrial DNA sequence variation in Finnish patients with matrilineal diabetes mellitus. BMC Res Notes 2012; 5:350. [PMID: 22780954 PMCID: PMC3434112 DOI: 10.1186/1756-0500-5-350] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 06/23/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The genetic background of type 2 diabetes is complex involving contribution by both nuclear and mitochondrial genes. There is an excess of maternal inheritance in patients with type 2 diabetes and, furthermore, diabetes is a common symptom in patients with mutations in mitochondrial DNA (mtDNA). Polymorphisms in mtDNA have been reported to act as risk factors in several complex diseases. FINDINGS We examined the nucleotide variation in complete mtDNA sequences of 64 Finnish patients with matrilineal diabetes. We used conformation sensitive gel electrophoresis and sequencing to detect sequence variation. We analysed the pathogenic potential of nonsynonymous variants detected in the sequences and examined the role of the m.16189 T>C variant. Controls consisted of non-diabetic subjects ascertained in the same population. The frequency of mtDNA haplogroup V was 3-fold higher in patients with diabetes. Patients harboured many nonsynonymous mtDNA substitutions that were predicted to be possibly or probably damaging. Furthermore, a novel m.13762 T>G in MTND5 leading to p.Ser476Ala and several rare mtDNA variants were found. Haplogroup H1b harbouring m.16189 T > C and m.3010 G > A was found to be more frequent in patients with diabetes than in controls. CONCLUSIONS Mildly deleterious nonsynonymous mtDNA variants and rare population-specific haplotypes constitute genetic risk factors for maternally inherited diabetes.
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Affiliation(s)
- Heidi K Soini
- Institute of Clinical Medicine, Department of Neurology, University of Oulu, P.O. Box 5000, FI-90014, Oulu, Finland
- Clinical Research Center, Oulu University Hospital, University of Oulu, P.O. Box 5000, FI-90014, Oulu, Finland
| | - Jukka S Moilanen
- Institute of Clinical Medicine, Department of Clinical Genetics, University of Oulu, P.O. Box 5000, FI-90014, Oulu, Finland
| | - Saara Finnila
- Institute of Clinical Medicine, Department of Neurology, University of Oulu, P.O. Box 5000, FI-90014, Oulu, Finland
| | - Kari Majamaa
- Institute of Clinical Medicine, Department of Neurology, University of Oulu, P.O. Box 5000, FI-90014, Oulu, Finland
- Clinical Research Center, Oulu University Hospital, University of Oulu, P.O. Box 5000, FI-90014, Oulu, Finland
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Jandova J, Shi M, Norman KG, Stricklin GP, Sligh JE. Somatic alterations in mitochondrial DNA produce changes in cell growth and metabolism supporting a tumorigenic phenotype. Biochim Biophys Acta Mol Basis Dis 2011; 1822:293-300. [PMID: 22119597 DOI: 10.1016/j.bbadis.2011.11.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 10/31/2011] [Accepted: 11/09/2011] [Indexed: 01/01/2023]
Abstract
There have been many reports of mitochondrial DNA (mtDNA) mutations associated with human malignancies. We have observed allelic instability in UV-induced cutaneous tumors at the mt-Tr locus encoding the mitochondrial tRNA for arginine. We examined the effects of somatic alterations at this locus by modeling the change in a uniform nuclear background by generating cybrids harboring allelic variation at mt-Tr. We utilized the naturally occurring mtDNA variation at mt-Tr within the BALB/cJ (BALB) and C57BL/6J (B6) strains of Mus musculus to transfer their mitochondria into a mouse ρ(0) cell line that lacked its own mtDNA. The BALB haplotype containing the mt-Tr 9821insA allele produced significant changes in cellular respiration (resulting in lowered ATP production), but increased rates of cellular proliferation in cybrid cells. Furthermore, the mtDNA genotype associated with UV-induced tumors endowed the cybrid cells with a phenotype of resistance to UV-induced apoptosis and enhanced migration and invasion capabilities. These studies support a role for mtDNA changes in cancer.
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Affiliation(s)
- Jana Jandova
- Southern Arizona VA Healthcare System and Department of Medicine, Dermatology Division, Arizona Cancer Center, University of Arizona, Tucson, AZ, USA
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Iwasaki S, Egami N, Fujimoto C, Chihara Y, Ushio M, Kashio A, Yamasoba T. The mitochondrial A3243G mutation involves the peripheral vestibule as well as the cochlea. Laryngoscope 2011; 121:1821-4. [PMID: 21792976 DOI: 10.1002/lary.21879] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Shinichi Iwasaki
- Department of Otolaryngology, Faculty of Medicine, University of Tokyo, Tokyo, Japan.
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Wang J, Venegas V, Li F, Wong L. Analysis of Mitochondrial DNA Point Mutation Heteroplasmy by ARMS Quantitative PCR. ACTA ACUST UNITED AC 2011; Chapter 19:Unit 19.6.. [DOI: 10.1002/0471142905.hg1906s68] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jing Wang
- Baylor College of Medicine Houston Texas
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Yarham JW, Elson JL, Blakely EL, McFarland R, Taylor RW. Mitochondrial tRNA mutations and disease. WILEY INTERDISCIPLINARY REVIEWS-RNA 2010; 1:304-24. [DOI: 10.1002/wrna.27] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- John W. Yarham
- Mitochondrial Research Group, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Joanna L. Elson
- Mitochondrial Research Group, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Emma L. Blakely
- Mitochondrial Research Group, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Robert McFarland
- Mitochondrial Research Group, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Robert W. Taylor
- Mitochondrial Research Group, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
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Hosszúfalusi N, Karcagi V, Horváth R, Palik E, Várkonyi J, Rajczy K, Prohászka Z, Szentirmai C, Karádi I, Romics L, Pánczél P. A detailed investigation of maternally inherited diabetes and deafness (MIDD) including clinical characteristics, C-peptide secretion, HLA-DR and -DQ status and autoantibody pattern. Diabetes Metab Res Rev 2009; 25:127-35. [PMID: 19116951 DOI: 10.1002/dmrr.841] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND This article presents a clinically characterization of the mitochondrial DNA mutation (A3243G) associated with maternally inherited diabetes and deafness (MIDD) syndrome in two families. METHODS Six patients with MIDD and one mutation-positive relative with normal glucose tolerance (NGT) were examined. Fasting serum C-peptide was measured in all subjects and compared with controls having NGT (n = 14). C-peptide response to an intravenous glucose tolerance test (IVGTT) was investigated in the diabetic patients not treated with insulin (n = 3) and in the mutation-positive healthy individual and compared with the controls. RESULTS The A3243G heteroplasmy value varied between 5 and 30%. All A3243G carriers had HLA-DR1-DQ5 haplotype, and either the -DQ5 or the -DQ6 allele. The fasting and the serum C-peptide levels at 120 min during the IVGTT did not differ between the A3243G carriers and the controls. A missing first phase and a decreased total C-peptide response was detected in the mutation-positive diabetics compared with controls (p < 0.0001). The same abnormality was found in the A3243G carrier with NGT. Circulating islet cell antibody (ICA) was present in three patients with MIDD. Glutamic acid decarboxylase (GAD), tyrosine phosphatase-like protein IA-2 (IA-2) and mitochondrial antibodies were missing. The diagnosis of MIDD was delayed in each case. CONCLUSIONS A missing first phase and a decreased total C-peptide response during an IVGTT was characteristic for the A3243G mutation. The fasting C-peptide level of the carriers did not differ from the controls. Circulating ICA was present in some patients, but GAD, IA-2 and mitochondrial antibodies were absent. All subjects had HLA-DR1-DQ5 haplotype, and either -DQ5 or -DQ6 alleles.
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Affiliation(s)
- Nóra Hosszúfalusi
- Semmelweis University, Budapest, 3rd Department of Internal Medicine, Budapest, Hungary.
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Sproule DM, Kaufmann P. Mitochondrial encephalopathy, lactic acidosis, and strokelike episodes: basic concepts, clinical phenotype, and therapeutic management of MELAS syndrome. Ann N Y Acad Sci 2008; 1142:133-58. [PMID: 18990125 DOI: 10.1196/annals.1444.011] [Citation(s) in RCA: 216] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Since the initial description almost 25 years ago, the syndrome of mitochondrial encephalopathy, lactic acidosis, and strokelike episodes (MELAS) has been a useful model to study the complex interplay of factors that define mitochondrial disease. This syndrome, most commonly caused by an A-to-G transition mutation at position 3243 of the mitochondrial genome, is typified by characteristic neurological manifestations including seizures, encephalopathy, and strokelike episodes, as well as other frequent secondary manifestations including short stature, cognitive impairment, migraines, depression, cardiomyopathy, cardiac conduction defects, and diabetes mellitus. In this review, we discuss the history, pathogenesis, clinical features, and diagnostic and management strategies of mitochondrial disease in general and of MELAS in particular. We explore features of mitochondrial genetics, including the concepts of heteroplasmy, mitotic segregation, and threshold effect, as a basis for understanding the variability and complicated inheritance patterns seen with this group of diseases. We also describe systemic manifestations of MELAS-associated mutations, including cardiac, renal, endocrine, gastrointestinal, and endothelial abnormalities and pathology, as well as the hypothetical role of derangements to COX enzymatic function in driving the unique pathology and clinical manifestations of MELAS. Although therapeutic options for MELAS and other mitochondrial diseases remain limited, and recent trials have been disappointing, we also consider current and potential therapeutic modalities.
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Affiliation(s)
- Douglas M Sproule
- Columbia University, Pediatric Neurology, 180 Fort Washington Ave., Harkness Pavilion, 5th floor, New York, NY 10032, USA.
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Janssen AJM, Schuelke M, Smeitink JAM, Trijbels FJM, Sengers RCA, Lucke B, Wintjes LTM, Morava E, van Engelen BGM, Smits BW, Hol FA, Siers MH, Ter Laak H, van der Knaap MS, Van Spronsen FJ, Rodenburg RJT, van den Heuvel LP. Muscle 3243A-->G mutation load and capacity of the mitochondrial energy-generating system. Ann Neurol 2008; 63:473-81. [PMID: 18306232 DOI: 10.1002/ana.21328] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE The mitochondrial energy-generating system (MEGS) encompasses the mitochondrial enzymatic reactions from oxidation of pyruvate to the export of adenosine triphosphate. It is investigated in intact muscle mitochondria by measuring the pyruvate oxidation and adenosine triphosphate production rates, which we refer to as the "MEGS capacity." Currently, little is known about MEGS pathology in patients with mutations in the mitochondrial DNA. Because MEGS capacity is an indicator for the overall mitochondrial function related to energy production, we searched for a correlation between MEGS capacity and 3243A-->G mutation load in muscle of patients with the MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes) syndrome. METHODS In muscle tissue of 24 patients with the 3243A-->G mutation, we investigated the MEGS capacity, the respiratory chain enzymatic activities, and the 3243A-->G mutation load. To exclude coinciding mutations, we sequenced all 22 mitochondrial transfer RNA genes in the patients, if possible. RESULTS We found highly significant differences between patients and control subjects with respect to the MEGS capacity and complex I, III, and IV activities. MEGS-related measurements correlated considerably better with the mutation load than respiratory chain enzyme activities. We found no additional mutations in the mitochondrial transfer RNA genes of the patients. INTERPRETATION The results show that MEGS capacity has a greater sensitivity than respiratory chain enzymatic activities for detection of subtle mitochondrial dysfunction. This is important in the workup of patients with rare or new mitochondrial DNA mutations, and with low mutation loads. In these cases we suggest to determine the MEGS capacity.
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Affiliation(s)
- Antoon J M Janssen
- Department of Pediatrics and Laboratory of Pediatrics and Neurology, Nijmegen Centre for Mitochondrial Disorders, Radboud University Medical Centre, Nijmegen, The Netherlands
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Vaxillaire M, Froguel P. Monogenic diabetes in the young, pharmacogenetics and relevance to multifactorial forms of type 2 diabetes. Endocr Rev 2008; 29:254-64. [PMID: 18436708 DOI: 10.1210/er.2007-0024] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Most valuable breakthroughs in the genetics of type 2 diabetes for the past two decades have arisen from candidate gene studies and familial linkage analysis of maturity-onset diabetes of the young (MODY), an autosomal dominant form of diabetes typically occurring before 25 years of age caused by primary insulin secretion defects. Despite its low prevalence, MODY is not a single entity but presents genetic, metabolic and clinical heterogeneity. MODY can result from mutations in at least six different genes encoding the glucose sensor enzyme glucokinase and transcription factors that participate in a regulatory network essential for adult beta-cell function. Additional genes have been described in other discrete phenotypes or syndromic forms of diabetes. Whereas common variants in the MODY genes contribute very modestly to type 2 diabetes susceptibility in adults, major findings emerging from the advent of genome-wide association studies will deliver an increasing number of genes and new pathways for the pathological events of the disease.
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Affiliation(s)
- Martine Vaxillaire
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8090, Institute of Biology and Pasteur Institute, Lille, France
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Salles JEN, Kalinin LB, Ferreira SRG, Kasamatsu T, Moisés RS. Diabetes mellitus associado à mutação mitocondrial A3243G: freqüência e caracterização clínica. ACTA ACUST UNITED AC 2007; 51:559-65. [PMID: 17684616 DOI: 10.1590/s0004-27302007000400009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2006] [Accepted: 12/13/2006] [Indexed: 11/22/2022]
Abstract
Diabetes mitocondrial é freqüentemente associado à mutação mitocondrial A3243G. A prevalência desse subtipo de diabetes na população diabética varia de 0,5 a 3%, dependendo do grupo populacional estudado. OBJETIVO: Examinar a freqüência e o quadro clínico do diabetes associado com a mutação mitocondrial A3243G em pacientes brasileiros com tolerância a glicose alterada. MÉTODOS: A população estudada foi composta por 78 indivíduos portadores de diabetes mellitus tipo 1 (grupo I), 148 diabéticos tipo 2 (grupo II), 15 diabéticos tipo 1 ou tipo 2 portadores de disacusia (grupo III) e 492 indivíduos da comunidade nipo-brasileira com vários graus de intolerância a glicose. O DNA foi extraído de leucócitos do sangue periférico e a mutação A3243G foi determinada através da amplificação por PCR e digestão por Apa 1. Em alguns pacientes, o DNA também foi extraído da mucosa oral e folículo capilar. A mutação A3243G foi identificada em três indivíduos, todos do grupo III, resultando em uma prevalência de 0,4%. Os carreadores da mutação apresentavam diagnóstico do diabetes em idade jovem, índice de massa corpórea normal ou baixo e requerimento de insulina. CONCLUSÃO: Diabetes mitocondrial é um subtipo raro de diabetes em nossa população e deve ser investigado naqueles indivíduos portadores de diabetes e surdez.
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Affiliation(s)
- João Eduardo N Salles
- Departamento de Medicina, Universidade Federal de São Paulo, Rua Botucatu 740, 04034-970 São Paulo, SP
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Manwaring N, Jones MM, Wang JJ, Rochtchina E, Howard C, Mitchell P, Sue CM. Population prevalence of the MELAS A3243G mutation. Mitochondrion 2007; 7:230-3. [PMID: 17300999 DOI: 10.1016/j.mito.2006.12.004] [Citation(s) in RCA: 186] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2006] [Revised: 12/05/2006] [Accepted: 12/27/2006] [Indexed: 10/23/2022]
Abstract
We aimed to establish the population prevalence of the MELAS 3243A>G mtDNA mutation in a large Caucasian-based population (n=2954; 99% Caucasian, 57% women and mean age of 66.4 years). All participants underwent comprehensive clinical evaluation including audiologic testing. We detected the 3243A>G mutation in seven subjects using standard polymerase chain reaction/restriction fragment length polymorphism methods, establishing a population prevalence of 236/100000 (0.24%; 95% CI 0.10-0.49%); much higher than previously reported. All had mild to moderate hearing loss. Our findings indicate that subjects with the 3243A>G mtDNA mutation could be markedly under-recognised in the community.
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Affiliation(s)
- Neil Manwaring
- Kolling Institute, Department of Neurogenetics, University of Sydney, Clinic 4, Royal North Shore Hospital, Reserve Road, St. Leonards, NSW 2065, Australia
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Raule N, Sevini F, Santoro A, Altilia S, Franceschi C. Association studies on human mitochondrial DNA: methodological aspects and results in the most common age-related diseases. Mitochondrion 2006; 7:29-38. [PMID: 17306632 DOI: 10.1016/j.mito.2006.11.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2006] [Accepted: 09/21/2006] [Indexed: 11/15/2022]
Abstract
Mitochondrial DNA (mtDNA) follows direct maternal inheritance and, as such, can be used in phylogenetic studies to determine a human lineage tree. The presence of common polymorphisms allows a classification of mtDNA in haplogroups and sub-haplogroups, according to the branch they belong to. Thanks to the rapidly growing number of mtDNA sequences available, this classification is being corrected and redefined to be more accurate. In parallel with this process, several studies are trying to identify an association between common mtDNA polymorphisms and common complex traits, as hypothesized by the common disease-common variant theory. Here we review the associations already reported with the main age-related complex diseases and we identify the critical points (sample size, size of the recruiting area, careful matching between cases and controls regarding geographical origin and ethnicity, data quality checking) to be taken in account in planning such studies. On the whole, this research area is opening a new perspective as an important component of "mitochondrial medicine", capable of identifying new molecular targets for the diagnosis, prevention and treatment of common complex diseases.
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Affiliation(s)
- Nicola Raule
- Centro Interdipartimentale L. Galvani, via S. Giacomo 12, 40126 Bologna, Italy.
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49
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Scaglia F, Northrop JL. The mitochondrial myopathy encephalopathy, lactic acidosis with stroke-like episodes (MELAS) syndrome: a review of treatment options. CNS Drugs 2006; 20:443-64. [PMID: 16734497 DOI: 10.2165/00023210-200620060-00002] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Mitochondrial encephalomyopathies are a multisystemic group of disorders that are characterised by a wide range of biochemical and genetic mitochondrial defects and variable modes of inheritance. Among this group of disorders, the mitochondrial myopathy, encephalopathy, lactic acidosis with stroke-like episodes (MELAS) syndrome is one of the most frequently occurring, maternally inherited mitochondrial disorders. As the name implies, stroke-like episodes are the defining feature of the MELAS syndrome, often occurring before the age of 15 years. The clinical course of this disorder is highly variable, ranging from asymptomatic, with normal early development, to progressive muscle weakness, lactic acidosis, cognitive dysfunction, seizures, stroke-like episodes, encephalopathy and premature death. This syndrome is associated with a number of point mutations in the mitochondrial DNA, with over 80% of the mutations occurring in the dihydrouridine loop of the mitochondrial transfer RNA(Leu(UUR)) [tRNA(Leu)((UUR))] gene. The pathophysiology of the disease is not completely understood; however, several different mechanisms are proposed to contribute to this disease. These include decreased aminoacylation of mitochondrial tRNA, resulting in decreased mitochondrial protein synthesis; changes in calcium homeostasis; and alterations in nitric oxide metabolism. Currently, no consensus criteria exist for treating the MELAS syndrome or mitochondrial dysfunction in other diseases. Many of the therapeutic strategies used have been adopted as the result of isolated case reports or limited clinical studies that have included a heterogeneous population of patients with the MELAS syndrome, other defects in oxidative phosphorylation or lactic acidosis due to disorders of pyruvate metabolism. Current approaches to the treatment of the MELAS syndrome are based on the use of antioxidants, respiratory chain substrates and cofactors in the form of vitamins; however, no consistent benefits have been observed with these treatments.
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Affiliation(s)
- Fernando Scaglia
- Department of Molecular and Human Genetics, Baylor College of Medicine and Texas Children's Hospital, Houston, Texas 77030, USA.
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Wallace DC. A mitochondrial paradigm of metabolic and degenerative diseases, aging, and cancer: a dawn for evolutionary medicine. Annu Rev Genet 2006; 39:359-407. [PMID: 16285865 PMCID: PMC2821041 DOI: 10.1146/annurev.genet.39.110304.095751] [Citation(s) in RCA: 2342] [Impact Index Per Article: 130.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Life is the interplay between structure and energy, yet the role of energy deficiency in human disease has been poorly explored by modern medicine. Since the mitochondria use oxidative phosphorylation (OXPHOS) to convert dietary calories into usable energy, generating reactive oxygen species (ROS) as a toxic by-product, I hypothesize that mitochondrial dysfunction plays a central role in a wide range of age-related disorders and various forms of cancer. Because mitochondrial DNA (mtDNA) is present in thousands of copies per cell and encodes essential genes for energy production, I propose that the delayed-onset and progressive course of the age-related diseases results from the accumulation of somatic mutations in the mtDNAs of post-mitotic tissues. The tissue-specific manifestations of these diseases may result from the varying energetic roles and needs of the different tissues. The variation in the individual and regional predisposition to degenerative diseases and cancer may result from the interaction of modern dietary caloric intake and ancient mitochondrial genetic polymorphisms. Therefore the mitochondria provide a direct link between our environment and our genes and the mtDNA variants that permitted our forbears to energetically adapt to their ancestral homes are influencing our health today.
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Affiliation(s)
- Douglas C Wallace
- Center for Molecular and Mitochondrial Medicine and Genetics, Department of Ecology and Evolutionary Biology, University of California, Irvine, California 92697-3940, USA.
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