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Koyuncu H, Kara N, Dabak Ş. Investigation of the possible effects of night shift on telomere length and mtDNA copy number in nurses. NUCLEOSIDES, NUCLEOTIDES & NUCLEIC ACIDS 2024:1-14. [PMID: 38830229 DOI: 10.1080/15257770.2024.2348089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 04/22/2024] [Indexed: 06/05/2024]
Abstract
In this study, we aimed to investigate the impacts of altered circadian rhythm on telomere length and mtDNA copy number (mtDNA-CN) in nurses working night shifts. In our study, 52 healthy nurses working in shifts at Ondokuz Mayıs University Hospital and 45 healthy control subjects working during the day were included. qRT-PCR technique was used for the determination of telomere length and mtDNA-CN. It was observed that the shift-work group had poor sleep quality (p = 0.004), feeling tired (p < 0.01) and stressed (p = 0.02) more than control group working during the day. Nurses working in shifts were found to have 1.18 times longer telomeres with respect to the control group working during the day (p = 0.005). When compared among shift workers, poor sleep quality and insufficient sleep duration shortened telomeres (r = 0.32; p = 0.02). There was no statistically significantdisparity regarding mtDNA-CN among the nurses working in shifts and the control group working during the day (p = 0.07). Insufficient sleep was associated with decreased mtDNA-CN when shift-working nurses were compared according to sleep quality (p = 0.006). Furthermore, mtDNA-CN of nurses with poor sleep quality was correlated with lower mtDNA-CN in comparison to nurses with good sleep quality (r = 0.284; p = 0.04). The mtDNA-CN of the nurses was positively associated with the sleep duration the night sleep before the night shift (r = 0.32; p = 0.02). Inadequate sleep duration and quality were observed to cause a reduction in mtDNA-CN of nurses. In conclusion, it has been observed that poor sleep quality and duration are related to shortened telomere length and decreased mtDNA-CN in night shift nurses.
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Affiliation(s)
- Hilal Koyuncu
- Faculty of Medicine, Department of Medical Biology, Ondokuz Mayıs University, Samsun, Turkey
| | - Nurten Kara
- Faculty of Medicine, Department of Medical Biology, Ondokuz Mayıs University, Samsun, Turkey
| | - Şennur Dabak
- Faculty of Medicine, Department of Public Health, Ondokuz Mayıs University, Samsun, Turkey
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2
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Qi H, Yin YS, Yin ZY, Li X, Shuai JW. Mitochondrial outer membrane permeabilization and inner membrane permeabilization in regulating apoptosis and inflammation. J Theor Biol 2023; 571:111558. [PMID: 37327862 DOI: 10.1016/j.jtbi.2023.111558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Accepted: 06/05/2023] [Indexed: 06/18/2023]
Abstract
Recent studies delineate an intimate crosstalk between apoptosis and inflammation. However, the dynamic mechanism linking them by mitochondrial membrane permeabilization remains elusive. Here, we construct a mathematical model consisting of four functional modules. Bifurcation analysis reveals that bistability stems from Bcl-2 family member interaction and time series shows that the time difference between Cyt c and mtDNA release is around 30 min, which are consistent with previous works. The model predicts that Bax aggregation kinetic determines cells to undergo apoptosis or inflammation, and that modulating the inhibitory effect of caspase 3 on IFN-β production allows the concurrent occurrence of apoptosis and inflammation. This work provides a theoretical framework for exploring the mechanism of mitochondrial membrane permeabilization in controlling cell fate.
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Affiliation(s)
- Hong Qi
- Complex Systems Research Center, Shanxi University, Taiyuan, China; Wenzhou Key Laboratory of Biophysics, Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, China.
| | - Yu-Song Yin
- Complex Systems Research Center, Shanxi University, Taiyuan, China
| | - Zhi-Yong Yin
- School of Mathematics and Statistics, Guangxi Normal University, Guilin, China
| | - Xiang Li
- Department of Physics and Fujian Provincial Key Laboratory for Soft Functional Materials Research, Xiamen University, Xiamen, China
| | - Jian-Wei Shuai
- Wenzhou Key Laboratory of Biophysics, Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, China
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3
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Picca A, Guerra F, Calvani R, Coelho-Júnior HJ, Leeuwenburgh C, Bucci C, Marzetti E. The contribution of mitochondrial DNA alterations to aging, cancer, and neurodegeneration. Exp Gerontol 2023; 178:112203. [PMID: 37172915 DOI: 10.1016/j.exger.2023.112203] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 04/24/2023] [Accepted: 05/09/2023] [Indexed: 05/15/2023]
Abstract
Mitochondrial DNA (mtDNA) is as a double-stranded molecule existing in hundreds to thousands copies in cells depending on cell metabolism and exposure to endogenous and/or environmental stressors. The coordination of mtDNA replication and transcription regulates the pace of mitochondrial biogenesis to guarantee the minimum number of organelles per cell. mtDNA inheritance follows a maternal lineage, although bi-parental inheritance has been reported in some species and in the case of mitochondrial diseases in humans. mtDNA mutations (e.g., point mutations, deletions, copy number variations) have been identified in the setting of several human diseases. For instance, sporadic and inherited rare disorders involving the nervous system as well higher risk of developing cancer and neurodegenerative conditions, including Parkinson's and Alzheimer's disease, have been associated with polymorphic mtDNA variants. An accrual of mtDNA mutations has also been identified in several tissues and organs, including heart and muscle, of old experimental animals and humans, which may contribute to the development of aging phenotypes. The role played by mtDNA homeostasis and mtDNA quality control pathways in human health is actively investigated for the possibility of developing targeted therapeutics for a wide range of conditions.
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Affiliation(s)
- Anna Picca
- Department of Medicine and Surgery, LUM University, 70100 Casamassima, Italy; Fondazione Policlinico Universitario "Agostino Gemelli" IRCCS, 00168 Rome, Italy
| | - Flora Guerra
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy
| | - Riccardo Calvani
- Fondazione Policlinico Universitario "Agostino Gemelli" IRCCS, 00168 Rome, Italy; Department of Geriatrics and Orthopedics, Università Cattolica del Sacro Cuore, 00168 Rome, Italy.
| | - Hélio José Coelho-Júnior
- Department of Geriatrics and Orthopedics, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
| | | | - Cecilia Bucci
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy
| | - Emanuele Marzetti
- Fondazione Policlinico Universitario "Agostino Gemelli" IRCCS, 00168 Rome, Italy; Department of Geriatrics and Orthopedics, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
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4
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Houshmand M, Zeinali V, Hosseini A, Seifi A, Danaei B, Kamfar S. Investigation of FGF21 mRNA levels and relative mitochondrial DNA copy number levels and their relation in nonalcoholic fatty liver disease: a case-control study. Front Mol Biosci 2023; 10:1203019. [PMID: 37347041 PMCID: PMC10279952 DOI: 10.3389/fmolb.2023.1203019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 05/22/2023] [Indexed: 06/23/2023] Open
Abstract
Background: Although the exact mechanisms of nonalcoholic fatty liver disease (NAFLD) are not fully understood, numerous pieces of evidence show that the variations in mitochondrial DNA (mtDNA) level and hepatic Fibroblast growth factor 21 (FGF21) expression may be related to NAFLD susceptibility. Objectives: The main objective of this study was to determine relative levels of mtDNA copy number and hepatic FGF21 expression in a cohort of Iranian NAFLD patients and evaluate the possible relationship. Methods: This study included 27 NAFLD patients (10 with nonalcoholic fatty liver (NAFL) and 17 with non-alcoholic steatohepatitis (NASH)) and ten healthy subjects. Total RNA and genomic DNA were extracted from liver tissue samples, and then mtDNA copy number and FGF21 expression levels were assessed by quantitative real-time PCR. Results: The relative level of hepatic mtDNA copy number was 3.9-fold higher in patients than in controls (p < 0.0001). NAFLD patients showed a 2.9-fold increase in hepatic FGF21 expression compared to controls (p < 0.013). Results showed that hepatic FGF21 expression was positively correlated with BMI, serum ALT, and AST levels (p < 0.05). The level of mitochondrial copy number and hepatic FGF21 expression was not significantly associated with stages of change in hepatic steatosis. Finally, there was a significant correlation between FGF21 expression and mitochondrial copy number in NAFLD patients (p = 0.027). Conclusion: Our findings suggest a considerable rise of hepatic FGF21 mRNA levels and mtDNA-CN and show a positive correlation between them in the liver tissue of NAFLD patients.
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Affiliation(s)
- Massoud Houshmand
- Department of Medical Genetics, National Institute for Genetic Engineering and Biotechnology, Tehran, Iran
| | - Vahide Zeinali
- Research Institute for Children’s Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Amirhossein Hosseini
- Pediatric Gastroenterology, Hepatology, and Nutrition Research Center, Research Institute for Children’s Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Atena Seifi
- Pediatric Nephrology Research Center, Research Institute for Children’s Health, Shahid Beheshti University of Medical Science, Tehran, Iran
| | - Bardia Danaei
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sharareh Kamfar
- Pediatric Congenital Hematologic Disorders Research Center, Research Institute for Children’s Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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5
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Tsyba N, Feng G, Grub LK, Held JP, Strozak AM, Burkewitz K, Patel MR. Tissue-specific heteroplasmy segregation is accompanied by a sharp mtDNA decline in Caenorhabditis elegans soma. iScience 2023; 26:106349. [PMID: 36968071 PMCID: PMC10031119 DOI: 10.1016/j.isci.2023.106349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/08/2022] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
Mutations in the mitochondrial genome (mtDNA) can be pathogenic. Owing to the multi-copy nature of mtDNA, wild-type copies can compensate for the effects of mutant mtDNA. Wild-type copies available for compensation vary depending on the mutant load and the total copy number. Here, we examine both mutant load and copy number in the tissues of Caenorhabditis elegans. We found that neurons, but not muscles, have modestly higher mutant load than rest of the soma. We also uncovered different effect of aak-2 knockout on the mutant load in the two tissues. The most surprising result was a sharp decline in somatic mtDNA content over time. The scale of the copy number decline surpasses the modest shifts in mutant load, suggesting that it may exert a substantial effect on mitochondrial function. In summary, measuring both the copy number and the mutant load provides a more comprehensive view of the mutant mtDNA dynamics.
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Affiliation(s)
- Nikita Tsyba
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA
| | - Gaomin Feng
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN37232, USA
| | - Lantana K. Grub
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA
| | - James P. Held
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA
| | - Adrianna M. Strozak
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA
| | - Kristopher Burkewitz
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN37232, USA
| | - Maulik R. Patel
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN37232, USA
- Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, TN37232, USA
- Evolutionary Studies, Vanderbilt University, Nashville, TN37235, USA
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6
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Otsuka T, Matsui H. Fish Models for Exploring Mitochondrial Dysfunction Affecting Neurodegenerative Disorders. Int J Mol Sci 2023; 24:ijms24087079. [PMID: 37108237 PMCID: PMC10138900 DOI: 10.3390/ijms24087079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/05/2023] [Accepted: 04/10/2023] [Indexed: 04/29/2023] Open
Abstract
Neurodegenerative disorders are characterized by the progressive loss of neuronal structure or function, resulting in memory loss and movement disorders. Although the detailed pathogenic mechanism has not been elucidated, it is thought to be related to the loss of mitochondrial function in the process of aging. Animal models that mimic the pathology of a disease are essential for understanding human diseases. In recent years, small fish have become ideal vertebrate models for human disease due to their high genetic and histological homology to humans, ease of in vivo imaging, and ease of genetic manipulation. In this review, we first outline the impact of mitochondrial dysfunction on the progression of neurodegenerative diseases. Then, we highlight the advantages of small fish as model organisms, and present examples of previous studies regarding mitochondria-related neuronal disorders. Lastly, we discuss the applicability of the turquoise killifish, a unique model for aging research, as a model for neurodegenerative diseases. Small fish models are expected to advance our understanding of the mitochondrial function in vivo, the pathogenesis of neurodegenerative diseases, and be important tools for developing therapies to treat diseases.
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Affiliation(s)
- Takayoshi Otsuka
- Department of Neuroscience of Disease, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Hideaki Matsui
- Department of Neuroscience of Disease, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
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7
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Liu H, Cai B, Gong R, Yang Y, Wang J, Zhou D, Yu M, Li Y. Impact of genetically predicted characterization of mitochondrial DNA quantity and quality on osteoarthritis. Front Genet 2023; 14:1130411. [PMID: 36911418 PMCID: PMC9998702 DOI: 10.3389/fgene.2023.1130411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 02/13/2023] [Indexed: 02/26/2023] Open
Abstract
Background: Existing studies have indicated that mitochondrial dysfunction may contribute to osteoarthritis (OA) development. However, the causal association between mitochondrial DNA (mtDNA) characterization and OA has not been extensively explored. Methods: Two-sample Mendelian randomization was performed to calculate the impact of mitochondrial genomic variations on overall OA as well as site-specific OA, with multiple analytical methods inverse variance weighted (IVW), weighted median (WM), MR-Egger and MR-robust adjusted profile score (MR-RAPS). Results: Genetically determined mitochondrial heteroplasmy (MtHz) and mtDNA abundance were not causally associated with overall OA. In site-specific OA analyses, the causal effect of mtDNA abundance on other OA sites, including hip, knee, thumb, hand, and finger, had not been discovered. There was a suggestively protective effect of MtHz on knee OA IVW OR = 0.632, 95% CI: 0.425-0.939, p-value = 0.023. No causal association between MtHz and other different OA phenotypes was found. Conclusion: MtHz shows potential to be a novel therapeutic target and biomarker on knee OA development. However, the variation of mtDNA abundance was measured from leukocyte in blood and the levels of MtHz were from saliva samples rather than cartilage or synovial tissues. Genotyping samples from synovial and cartilage can be a focus to further exploration.
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Affiliation(s)
- Houpu Liu
- Department of Epidemiology and Health Statistics, School of Public Health, Hangzhou Medical College, Hangzhou, China
| | - Bingyue Cai
- Department of Epidemiology and Health Statistics, School of Public Health, Hangzhou Medical College, Hangzhou, China
| | | | - Ye Yang
- Department of Epidemiology and Health Statistics, School of Public Health, Hangzhou Medical College, Hangzhou, China
| | - Jing Wang
- Department of Epidemiology and Health Statistics, School of Public Health, Hangzhou Medical College, Hangzhou, China
| | - Dan Zhou
- Department of Big Data in Health Science, School of Public Health, Zhejiang University School of Medicine, Hangzhou, China.,Vanderbit Genetics Institute, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Min Yu
- Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, China
| | - Yingjun Li
- Department of Epidemiology and Health Statistics, School of Public Health, Hangzhou Medical College, Hangzhou, China
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8
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Energy substrate metabolism and oxidative stress in metabolic cardiomyopathy. J Mol Med (Berl) 2022; 100:1721-1739. [PMID: 36396746 DOI: 10.1007/s00109-022-02269-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 10/17/2022] [Accepted: 10/20/2022] [Indexed: 11/18/2022]
Abstract
Metabolic cardiomyopathy is an emerging cause of heart failure in patients with obesity, insulin resistance, and diabetes. It is characterized by impaired myocardial metabolic flexibility, intramyocardial triglyceride accumulation, and lipotoxic damage in association with structural and functional alterations of the heart, unrelated to hypertension, coronary artery disease, and other cardiovascular diseases. Oxidative stress plays an important role in the development and progression of metabolic cardiomyopathy. Mitochondria are the most significant sources of reactive oxygen species (ROS) in cardiomyocytes. Disturbances in myocardial substrate metabolism induce mitochondrial adaptation and dysfunction, manifested as a mismatch between mitochondrial fatty acid oxidation and the electron transport chain (ETC) activity, which facilitates ROS production within the ETC components. In addition, non-ETC sources of mitochondrial ROS, such as β-oxidation of fatty acids, may also produce a considerable quantity of ROS in metabolic cardiomyopathy. Augmented ROS production in cardiomyocytes can induce a variety of effects, including the programming of myocardial energy substrate metabolism, modulation of metabolic inflammation, redox modification of ion channels and transporters, and cardiomyocyte apoptosis, ultimately leading to the structural and functional alterations of the heart. Based on the above mechanistic views, the present review summarizes the current understanding of the mechanisms underlying metabolic cardiomyopathy, focusing on the role of oxidative stress.
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9
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Gureev AP, Andrianova NV, Pevzner IB, Zorova LD, Chernyshova EV, Sadovnikova IS, Chistyakov DV, Popkov VA, Semenovich DS, Babenko VA, Silachev DN, Zorov DB, Plotnikov EY, Popov VN. Dietary restriction modulates mitochondrial DNA damage and oxylipin profile in aged rats. FEBS J 2022; 289:5697-5713. [DOI: 10.1111/febs.16451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 03/16/2022] [Accepted: 04/01/2022] [Indexed: 11/28/2022]
Affiliation(s)
- Artem P. Gureev
- Department of Genetics, Cytology and Bioengineering Voronezh State University Voronezh Russia
- Laboratory of Metagenomics and Food Biotechnology Voronezh State University of Engineering Technology Voronezh Russia
| | - Nadezda V. Andrianova
- Belozersky Institute of Physico‐Chemical Biology Lomonosov Moscow State University Moscow Russia
| | - Irina B. Pevzner
- Belozersky Institute of Physico‐Chemical Biology Lomonosov Moscow State University Moscow Russia
- Kulakov National Medical Research Center of Obstetrics, Gynecology, and Perinatology Moscow Russia
| | - Ljubava D. Zorova
- Belozersky Institute of Physico‐Chemical Biology Lomonosov Moscow State University Moscow Russia
- Kulakov National Medical Research Center of Obstetrics, Gynecology, and Perinatology Moscow Russia
| | | | - Irina S. Sadovnikova
- Department of Genetics, Cytology and Bioengineering Voronezh State University Voronezh Russia
| | - Dmitry V. Chistyakov
- Belozersky Institute of Physico‐Chemical Biology Lomonosov Moscow State University Moscow Russia
| | - Vasily A. Popkov
- Belozersky Institute of Physico‐Chemical Biology Lomonosov Moscow State University Moscow Russia
- Kulakov National Medical Research Center of Obstetrics, Gynecology, and Perinatology Moscow Russia
| | - Dmitry S. Semenovich
- Belozersky Institute of Physico‐Chemical Biology Lomonosov Moscow State University Moscow Russia
| | - Valentina A. Babenko
- Belozersky Institute of Physico‐Chemical Biology Lomonosov Moscow State University Moscow Russia
- Kulakov National Medical Research Center of Obstetrics, Gynecology, and Perinatology Moscow Russia
| | - Denis N. Silachev
- Belozersky Institute of Physico‐Chemical Biology Lomonosov Moscow State University Moscow Russia
- Kulakov National Medical Research Center of Obstetrics, Gynecology, and Perinatology Moscow Russia
| | - Dmitry B. Zorov
- Belozersky Institute of Physico‐Chemical Biology Lomonosov Moscow State University Moscow Russia
- Kulakov National Medical Research Center of Obstetrics, Gynecology, and Perinatology Moscow Russia
| | - Egor Y. Plotnikov
- Belozersky Institute of Physico‐Chemical Biology Lomonosov Moscow State University Moscow Russia
- Kulakov National Medical Research Center of Obstetrics, Gynecology, and Perinatology Moscow Russia
| | - Vasily N. Popov
- Department of Genetics, Cytology and Bioengineering Voronezh State University Voronezh Russia
- Laboratory of Metagenomics and Food Biotechnology Voronezh State University of Engineering Technology Voronezh Russia
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10
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Das SC, Hjelm BE, Rollins BL, Sequeira A, Morgan L, Omidsalar AA, Schatzberg AF, Barchas JD, Lee FS, Myers RM, Watson SJ, Akil H, Bunney WE, Vawter MP. Mitochondria DNA copy number, mitochondria DNA total somatic deletions, Complex I activity, synapse number, and synaptic mitochondria number are altered in schizophrenia and bipolar disorder. Transl Psychiatry 2022; 12:353. [PMID: 36042222 PMCID: PMC9427957 DOI: 10.1038/s41398-022-02127-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 08/16/2022] [Accepted: 08/18/2022] [Indexed: 11/15/2022] Open
Abstract
Mitochondrial dysfunction is a neurobiological phenomenon implicated in the pathophysiology of schizophrenia and bipolar disorder that can synergistically affect synaptic neurotransmission. We hypothesized that schizophrenia and bipolar disorder share molecular alterations at the mitochondrial and synaptic levels. Mitochondria DNA (mtDNA) copy number (CN), mtDNA common deletion (CD), mtDNA total deletion, complex I activity, synapse number, and synaptic mitochondria number were studied in the postmortem human dorsolateral prefrontal cortex (DLPFC), superior temporal gyrus (STG), primary visual cortex (V1), and nucleus accumbens (NAc) of controls (CON), and subjects with schizophrenia (SZ), and bipolar disorder (BD). The results showed (i) the mtDNA CN is significantly higher in DLPFC of both SZ and BD, decreased in the STG of BD, and unaltered in V1 and NAc of both SZ and BD; (ii) the mtDNA CD is significantly higher in DLPFC of BD while unaltered in STG, V1, and NAc of both SZ and BD; (iii) The total deletion burden is significantly higher in DLPFC in both SZ and BD while unaltered in STG, V1, and NAc of SZ and BD; (iv) Complex I activity is significantly lower in DLPFC of both SZ and BD, which is driven by the presence of medications, with no alteration in STG, V1, and NAc. In addition, complex I protein concentration, by ELISA, was decreased across three cortical regions of SZ and BD subjects; (v) The number of synapses is decreased in DLPFC of both SZ and BD, while the synaptic mitochondria number was significantly lower in female SZ and female BD compared to female controls. Overall, these findings will pave the way to understand better the pathophysiology of schizophrenia and bipolar disorder for therapeutic interventions.
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Affiliation(s)
- Sujan C. Das
- grid.266093.80000 0001 0668 7243Functional Genomics Laboratory, Department of Psychiatry & Human Behavior, University of California, Irvine, CA USA
| | - Brooke E. Hjelm
- grid.42505.360000 0001 2156 6853Department of Translational Genomics, Keck School of Medicine, University of Southern California, Health Sciences Campus, Los Angeles, CA USA
| | - Brandi L. Rollins
- grid.266093.80000 0001 0668 7243Functional Genomics Laboratory, Department of Psychiatry & Human Behavior, University of California, Irvine, CA USA
| | - Adolfo Sequeira
- grid.266093.80000 0001 0668 7243Functional Genomics Laboratory, Department of Psychiatry & Human Behavior, University of California, Irvine, CA USA
| | - Ling Morgan
- grid.266093.80000 0001 0668 7243Functional Genomics Laboratory, Department of Psychiatry & Human Behavior, University of California, Irvine, CA USA
| | - Audrey A. Omidsalar
- grid.42505.360000 0001 2156 6853Department of Translational Genomics, Keck School of Medicine, University of Southern California, Health Sciences Campus, Los Angeles, CA USA
| | - Alan F. Schatzberg
- grid.168010.e0000000419368956Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA USA
| | - Jack D. Barchas
- grid.5386.8000000041936877XDepartment of Psychiatry, Weill Cornell Medical College, Ithaca, NJ USA
| | - Francis S. Lee
- grid.5386.8000000041936877XDepartment of Psychiatry, Weill Cornell Medical College, Ithaca, NJ USA
| | - Richard M. Myers
- grid.417691.c0000 0004 0408 3720HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806 USA
| | - Stanley J. Watson
- grid.214458.e0000000086837370The Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI USA
| | - Huda Akil
- grid.214458.e0000000086837370The Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI USA
| | - William E. Bunney
- grid.266093.80000 0001 0668 7243Department of Psychiatry & Human Behavior, University of California, Irvine, CA USA
| | - Marquis P. Vawter
- grid.266093.80000 0001 0668 7243Functional Genomics Laboratory, Department of Psychiatry & Human Behavior, University of California, Irvine, CA USA
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11
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Mitochondrial DNA Is a Vital Driving Force in Ischemia-Reperfusion Injury in Cardiovascular Diseases. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:6235747. [PMID: 35620580 PMCID: PMC9129988 DOI: 10.1155/2022/6235747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 05/06/2022] [Indexed: 11/28/2022]
Abstract
According to the latest Global Burden of Disease Study, cardiovascular disease (CVD) is the leading cause of death, and ischemic heart disease and stroke are the cause of death in approximately half of CVD patients. In CVD, mitochondrial dysfunction following ischemia-reperfusion (I/R) injury results in heart failure. The proper functioning of oxidative phosphorylation (OXPHOS) and the mitochondrial life cycle in cardiac mitochondria are closely related to mitochondrial DNA (mtDNA). Following myocardial I/R injury, mitochondria activate multiple repair and clearance mechanisms to repair damaged mtDNA. When these repair mechanisms are insufficient to restore the structure and function of mtDNA, irreversible mtDNA damage occurs, leading to mtDNA mutations. Since mtDNA mutations aggravate OXPHOS dysfunction and affect mitophagy, mtDNA mutation accumulation leads to leakage of mtDNA and proteins outside the mitochondria, inducing an innate immune response, aggravating cardiovascular injury, and leading to the need for external interventions to stop or slow the disease course. On the other hand, mtDNA released into the circulation after cardiac injury can serve as a biomarker for CVD diagnosis and prognosis. This article reviews the pathogenic basis and related research findings of mtDNA oxidative damage and mtDNA leak-triggered innate immune response associated with I/R injury in CVD and summarizes therapeutic options that target mtDNA.
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12
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Chen Y, Hamidu S, Yang X, Yan Y, Wang Q, Li L, Oduro PK, Li Y. Dietary Supplements and Natural Products: An Update on Their Clinical Effectiveness and Molecular Mechanisms of Action During Accelerated Biological Aging. Front Genet 2022; 13:880421. [PMID: 35571015 PMCID: PMC9096086 DOI: 10.3389/fgene.2022.880421] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 04/04/2022] [Indexed: 12/11/2022] Open
Abstract
Accelerated biological aging, which involves the gradual decline of organ or tissue functions and the distortion of physiological processes, underlies several human diseases. Away from the earlier free radical concept, telomere attrition, cellular senescence, proteostasis loss, mitochondrial dysfunction, stem cell exhaustion, and epigenetic and genomic alterations have emerged as biological hallmarks of aging. Moreover, nutrient-sensing metabolic pathways are critical to an organism’s ability to sense and respond to nutrient levels. Pharmaceutical, genetic, and nutritional interventions reverting physiological declines by targeting nutrient-sensing metabolic pathways can promote healthy aging and increase lifespan. On this basis, biological aging hallmarks and nutrient-sensing dependent and independent pathways represent evolving drug targets for many age-linked diseases. Here, we discuss and update the scientific community on contemporary advances in how dietary supplements and natural products beneficially revert accelerated biological aging processes to retrograde human aging and age-dependent human diseases, both from the clinical and preclinical studies point-of-view. Overall, our review suggests that dietary/natural products increase healthspan—rather than lifespan—effectively minimizing the period of frailty at the end of life. However, real-world setting clinical trials and basic studies on dietary supplements and natural products are further required to decisively demonstrate whether dietary/natural products could promote human lifespan.
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Affiliation(s)
- Ye Chen
- State Key Laboratory of Pharmacology of Modern Chinese Medicine, Department of Pharmacology and Toxicology, Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Sherif Hamidu
- Clinical Pathology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Xintong Yang
- State Key Laboratory of Pharmacology of Modern Chinese Medicine, Department of Pharmacology and Toxicology, Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Yiqi Yan
- State Key Laboratory of Pharmacology of Modern Chinese Medicine, Department of Pharmacology and Toxicology, Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Qilong Wang
- State Key Laboratory of Pharmacology of Modern Chinese Medicine, Department of Pharmacology and Toxicology, Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Lin Li
- State Key Laboratory of Pharmacology of Modern Chinese Medicine, Department of Pharmacology and Toxicology, Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Patrick Kwabena Oduro
- State Key Laboratory of Pharmacology of Modern Chinese Medicine, Department of Pharmacology and Toxicology, Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China.,Clinical Pathology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Yuhong Li
- State Key Laboratory of Pharmacology of Modern Chinese Medicine, Department of Pharmacology and Toxicology, Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
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Valiente-Pallejà A, Tortajada J, Bulduk BK, Vilella E, Garrabou G, Muntané G, Martorell L. Comprehensive summary of mitochondrial DNA alterations in the postmortem human brain: A systematic review. EBioMedicine 2022; 76:103815. [PMID: 35085849 PMCID: PMC8790490 DOI: 10.1016/j.ebiom.2022.103815] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 12/24/2021] [Accepted: 01/05/2022] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Mitochondrial DNA (mtDNA) encodes 37 genes necessary for synthesizing 13 essential subunits of the oxidative phosphorylation system. mtDNA alterations are known to cause mitochondrial disease (MitD), a clinically heterogeneous group of disorders that often present with neuropsychiatric symptoms. Understanding the nature and frequency of mtDNA alterations in health and disease could be a cornerstone in disentangling the relationship between biochemical findings and clinical symptoms of brain disorders. This systematic review aimed to summarize the mtDNA alterations in human brain tissue reported to date that have implications for further research on the pathophysiological significance of mtDNA alterations in brain functioning. METHODS We searched the PubMed and Embase databases using distinct terms related to postmortem human brain and mtDNA up to June 10, 2021. Reports were eligible if they were empirical studies analysing mtDNA in postmortem human brains. FINDINGS A total of 158 of 637 studies fulfilled the inclusion criteria and were clustered into the following groups: MitD (48 entries), neurological diseases (NeuD, 55 entries), psychiatric diseases (PsyD, 15 entries), a miscellaneous group with controls and other clinical diseases (5 entries), ageing (20 entries), and technical issues (5 entries). Ten entries were ascribed to more than one group. Pathogenic single nucleotide variants (pSNVs), both homo- or heteroplasmic variants, have been widely reported in MitD, with heteroplasmy levels varying among brain regions; however, pSNVs are rarer in NeuD, PsyD and ageing. A lower mtDNA copy number (CN) in disease was described in most, but not all, of the identified studies. mtDNA deletions were identified in individuals in the four clinical categories and ageing. Notably, brain samples showed significantly more mtDNA deletions and at higher heteroplasmy percentages than blood samples, and several of the deletions present in the brain were not detected in the blood. Finally, mtDNA heteroplasmy, mtDNA CN and the deletion levels varied depending on the brain region studied. INTERPRETATION mtDNA alterations are well known to affect human tissues, including the brain. In general, we found that studies of MitD, NeuD, PsyD, and ageing were highly variable in terms of the type of disease or ageing process investigated, number of screened individuals, studied brain regions and technology used. In NeuD and PsyD, no particular type of mtDNA alteration could be unequivocally assigned to any specific disease or diagnostic group. However, the presence of mtDNA deletions and mtDNA CN variation imply a role for mtDNA in NeuD and PsyD. Heteroplasmy levels and threshold effects, affected brain regions, and mitotic segregation patterns of mtDNA alterations may be involved in the complex inheritance of NeuD and PsyD and in the ageing process. Therefore, more information is needed regarding the type of mtDNA alteration, the affected brain regions, the heteroplasmy levels, and their relationship with clinical phenotypes and the ageing process. FUNDING Hospital Universitari Institut Pere Mata; Institut d'Investigació Sanitària Pere Virgili; Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación (PI18/00514).
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Affiliation(s)
- Alba Valiente-Pallejà
- Research Department, Hospital Universitari Institut Pere Mata (HUIPM); Institut d'Investigació Sanitària Pere Virgili (IISPV); Faculty of Medicine and Health Sciences, Universitat Rovira i Virgili (URV), 43201 Reus, Catalonia, Spain; Biomedical Network Research Centre on Mental Health (CIBERSAM), 28029 Madrid, Spain
| | - Juan Tortajada
- Research Department, Hospital Universitari Institut Pere Mata (HUIPM); Institut d'Investigació Sanitària Pere Virgili (IISPV); Faculty of Medicine and Health Sciences, Universitat Rovira i Virgili (URV), 43201 Reus, Catalonia, Spain; Biomedical Network Research Centre on Mental Health (CIBERSAM), 28029 Madrid, Spain
| | - Bengisu K Bulduk
- Research Department, Hospital Universitari Institut Pere Mata (HUIPM); Institut d'Investigació Sanitària Pere Virgili (IISPV); Faculty of Medicine and Health Sciences, Universitat Rovira i Virgili (URV), 43201 Reus, Catalonia, Spain; Biomedical Network Research Centre on Mental Health (CIBERSAM), 28029 Madrid, Spain
| | - Elisabet Vilella
- Research Department, Hospital Universitari Institut Pere Mata (HUIPM); Institut d'Investigació Sanitària Pere Virgili (IISPV); Faculty of Medicine and Health Sciences, Universitat Rovira i Virgili (URV), 43201 Reus, Catalonia, Spain; Biomedical Network Research Centre on Mental Health (CIBERSAM), 28029 Madrid, Spain
| | - Glòria Garrabou
- Laboratory of Muscle Research and Mitochondrial Function, Department of Internal Medicine-Hospital Clínic of Barcelona (HCB); Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS); Faculty of Medicine and Health Sciences, Universitat de Barcelona (UB), 08036 Barcelona, Catalonia, Spain; Biomedical Network Research Centre on Rare Diseases (CIBERER), 28029 Madrid, Spain
| | - Gerard Muntané
- Research Department, Hospital Universitari Institut Pere Mata (HUIPM); Institut d'Investigació Sanitària Pere Virgili (IISPV); Faculty of Medicine and Health Sciences, Universitat Rovira i Virgili (URV), 43201 Reus, Catalonia, Spain; Biomedical Network Research Centre on Mental Health (CIBERSAM), 28029 Madrid, Spain; Institute of Evolutionary Biology (IBE), Universitat Pompeu Fabra (UPF), 08003 Barcelona, Catalonia, Spain
| | - Lourdes Martorell
- Research Department, Hospital Universitari Institut Pere Mata (HUIPM); Institut d'Investigació Sanitària Pere Virgili (IISPV); Faculty of Medicine and Health Sciences, Universitat Rovira i Virgili (URV), 43201 Reus, Catalonia, Spain; Biomedical Network Research Centre on Mental Health (CIBERSAM), 28029 Madrid, Spain.
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Lyu L, Yu J, Liu Y, He S, Zhao Y, Qi M, Ping F, Xu L, Li W, Zhang H, Li Y. High Hemoglobin Glycation Index Is Associated With Telomere Attrition Independent of HbA1c, Mediated by TNFα. J Clin Endocrinol Metab 2022; 107:462-473. [PMID: 34562085 DOI: 10.1210/clinem/dgab703] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Indexed: 11/19/2022]
Abstract
CONTEXT The hemoglobin glycation index (HGI) is correlated with metabolic diseases and inflammation. Whether the HGI is associated with the aging process and how inflammation and oxidative stress affect the relationship remain unclear. OBJECTIVE We aimed to analyze links between the HGI and aging biomarkers, and to explore a potential role of inflammation and oxidative stress in the correlations. METHODS A cross-sectional study of 434 subjects with different glucose intolerances in a rural community was enrolled. The HGI was calculated as the difference between the measured and predicted hemoglobin A1c (HbA1c). The population was categorized into tertiles of the HGI. Telomere length (LTL) and mitochondrial DNA copy number (mtDNAcn) determined by polymerase chain reaction assay. Tumor necrosis factor (TNF) α and interleukin (IL) 6, 8-oxo-2'-deoxyguanosine (8-oxo-dG), superoxide dismutase (SOD) activities, and glutathione reductase (GR) were measured. RESULTS Participants in the high HGI group were older and reported a shorter LTL, higher levels of TNFα, SOD activities, and HbA1c. Correlation analyses demonstrated that HGI was correlated with LTL (r = -0.25, P < .001) and TNFα (r = 0.19, P < .001) regardless of HbA1c levels. No relationship was found between HGI and mtDNAcn. HGI (β = -0.238, 95% CI -0.430, -0.046, P = .015) and TNFα (β = -0.02, 95% CI -0.030, -0.014, P < .001) were proved to be correlated with LTL independently, using multiple linear regression analysis. Ordinal logistic regression models showed that compared with subjects the high HGI group, the possibilities of a higher-level LTL was 5.29-fold in the low HGI group (OR 5.29, 95% CI (2.45, 11.41), P < .001), 2.41-fold in the moderate HGI group (OR 2.41, 95% CI 1.35, 4.30, P = .003) after controlling for confounding variables. Mediation analyses indicated that TNFα accounted for 30.39% of the effects of the HGI on LTL. CONCLUSION HGI was negatively related to telomere attrition, independent of HbA1c. TNFα acted as a mediator of the relationship between HGI and LTL.
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Affiliation(s)
- Lu Lyu
- Department of Endocrinology, NHC Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Jie Yu
- Department of Endocrinology, NHC Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Yiwen Liu
- Department of Endocrinology, NHC Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Shuli He
- Department of Nutrition, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Yuan Zhao
- Department of Endocrinology, NHC Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Mengya Qi
- Department of Endocrinology, NHC Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Fan Ping
- Department of Endocrinology, NHC Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Lingling Xu
- Department of Endocrinology, NHC Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Wei Li
- Department of Endocrinology, NHC Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Huabing Zhang
- Department of Endocrinology, NHC Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Yuxiu Li
- Department of Endocrinology, NHC Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
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15
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Chong M, Mohammadi-Shemirani P, Perrot N, Nelson W, Morton R, Narula S, Lali R, Khan I, Khan M, Judge C, Machipisa T, Cawte N, O'Donnell M, Pigeyre M, Akhabir L, Paré G. GWAS and ExWAS of blood Mitochondrial DNA copy number identifies 71 loci and highlights a potential causal role in dementia. eLife 2022; 11:70382. [PMID: 35023831 PMCID: PMC8865845 DOI: 10.7554/elife.70382] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 01/11/2022] [Indexed: 12/16/2022] Open
Abstract
Background: Mitochondrial DNA copy number (mtDNA-CN) is an accessible blood-based measurement believed to capture underlying mitochondrial (MT) function. The specific biological processes underpinning its regulation, and whether those processes are causative for disease, is an area of active investigation. Methods: We developed a novel method for array-based mtDNA-CN estimation suitable for biobank-scale studies, called ‘automatic mitochondrial copy (AutoMitoC).’ We applied AutoMitoC to 395,781 UKBiobank study participants and performed genome- and exome-wide association studies, identifying novel common and rare genetic determinants. Finally, we performed two-sample Mendelian randomization to assess whether genetically low mtDNA-CN influenced select MT phenotypes. Results: Overall, genetic analyses identified 71 loci for mtDNA-CN, which implicated several genes involved in rare mtDNA depletion disorders, deoxynucleoside triphosphate (dNTP) metabolism, and the MT central dogma. Rare variant analysis identified SAMHD1 mutation carriers as having higher mtDNA-CN (beta = 0.23 SDs; 95% CI, 0.18–0.29; p=2.6 × 10-19), a potential therapeutic target for patients with mtDNA depletion disorders, but at increased risk of breast cancer (OR = 1.91; 95% CI, 1.52–2.40; p=2.7 × 10-8). Finally, Mendelian randomization analyses suggest a causal effect of low mtDNA-CN on dementia risk (OR = 1.94 per 1 SD decrease in mtDNA-CN; 95% CI, 1.55–2.32; p=7.5 × 10-4). Conclusions: Altogether, our genetic findings indicate that mtDNA-CN is a complex biomarker reflecting specific MT processes related to mtDNA regulation, and that these processes are causally related to human diseases. Funding: No funds supported this specific investigation. Awards and positions supporting authors include: Canadian Institutes of Health Research (CIHR) Frederick Banting and Charles Best Canada Graduate Scholarships Doctoral Award (MC, PM); CIHR Post-Doctoral Fellowship Award (RM); Wellcome Trust Grant number: 099313/B/12/A; Crasnow Travel Scholarship; Bongani Mayosi UCT-PHRI Scholarship 2019/2020 (TM); Wellcome Trust Health Research Board Irish Clinical Academic Training (ICAT) Programme Grant Number: 203930/B/16/Z (CJ); European Research Council COSIP Grant Number: 640580 (MO); E.J. Moran Campbell Internal Career Research Award (MP); CISCO Professorship in Integrated Health Systems and Canada Research Chair in Genetic and Molecular Epidemiology (GP) Our cells are powered by small internal compartments known as mitochondria, which host several copies of their own ‘mitochondrial’ genome. Defects in these semi-autonomous structures are associated with a range of severe, and sometimes fatal conditions: easily checking the health of mitochondria through cheap, quick and non-invasive methods can therefore help to improve human health. Measuring the concentration of mitochondrial DNA molecules in our blood cells can help to estimate the number of mitochondrial genome copies per cell, which in turn act as a proxy for the health of the compartment. In fact, having lower or higher concentration of mitochondrial DNA molecules is associated with diseases such as cancer, stroke, or cardiac conditions. However, current approaches to assess this biomarker are time and resource-intensive; they also do not work well across people with different ancestries, who have slightly different versions of mitochondrial genomes. In response, Chong et al. developed a new method for estimating mitochondrial DNA concentration in blood samples. Called AutoMitoC, the automated pipeline is fast, easy to use, and can be used across ethnicities. Applying this method to nearly 400,000 individuals highlighted 71 genetic regions for which slight sequence differences were associated with changes in mitochondrial DNA concentration. Further investigation revealed that these regions contained genes that help to build, maintain, and organize mitochondrial DNA. In addition, the analyses yield preliminary evidence showing that lower concentration of mitochondrial DNA may be linked to a higher risk of dementia. Overall, the work by Chong et al. demonstrates that AutoMitoC can be used to investigate how mitochondria are linked to health and disease in populations across the world, potentially paving the way for new therapeutic approaches.
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Affiliation(s)
- Michael Chong
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | | | | | - Walter Nelson
- Centre for Data Science and Digital Health, Hamilton Health Sciences, Hamilton, Canada
| | - Robert Morton
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada
| | - Sukrit Narula
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Canada
| | - Ricky Lali
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Canada
| | - Irfan Khan
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada
| | - Mohammad Khan
- Department of Medicine, McMaster University, Hamilton, Canada
| | - Conor Judge
- National University of Ireland, Galway, Galway, Ireland
| | - Tafadzwa Machipisa
- Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Nathan Cawte
- Population Health Research Institute, Hamilton, Canada
| | | | - Marie Pigeyre
- Department of Medicine, McMaster University, Hamilton, Canada
| | - Loubna Akhabir
- Department of Medicine, McMaster University, Hamilton, Canada
| | - Guillaume Paré
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada
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Klein HU, Trumpff C, Yang HS, Lee AJ, Picard M, Bennett DA, De Jager PL. Characterization of mitochondrial DNA quantity and quality in the human aged and Alzheimer's disease brain. Mol Neurodegener 2021; 16:75. [PMID: 34742335 PMCID: PMC8572491 DOI: 10.1186/s13024-021-00495-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 10/11/2021] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Mitochondrial dysfunction is a feature of neurodegenerative diseases, including Alzheimer's disease (AD). Changes in the mitochondrial DNA copy number (mtDNAcn) and increased mitochondrial DNA mutation burden have both been associated with neurodegenerative diseases and cognitive decline. This study aims to systematically identify which common brain pathologies in the aged human brain are associated with mitochondrial recalibrations and to disentangle the relationship between these pathologies, mtDNAcn, mtDNA heteroplasmy, aging, neuronal loss, and cognitive function. METHODS Whole-genome sequencing data from n = 1361 human brain samples from 5 different regions were used to quantify mtDNAcn as well as heteroplasmic mtDNA point mutations and small indels. Brain samples were assessed for 10 common pathologies. Annual cognitive test results were used to assess cognitive function proximal to death. For a subset of samples, neuronal proportions were estimated from RNA-seq profiles, and mass spectrometry was used to quantify the mitochondrial protein content of the tissue. RESULTS mtDNAcn was 7-14% lower in AD relative to control participants. When accounting for all 10 common neuropathologies, only tau was significantly associated with lower mtDNAcn in the dorsolateral prefrontal cortex. In the posterior cingulate cortex, TDP-43 pathology demonstrated a distinct association with mtDNAcn. No changes were observed in the cerebellum, which is affected late by pathologies. Neither age nor gender was associated with mtDNAcn in the studied brain regions when adjusting for pathologies. Mitochondrial content and mtDNAcn independently explained variance in cognitive function unaccounted by pathologies, implicating complex mitochondrial recalibrations in cognitive decline. In contrast, mtDNA heteroplasmy levels increased by 1.5% per year of life in the cortical regions, but displayed no association with any of the pathologies or cognitive function. CONCLUSIONS We studied mtDNA quantity and quality in relation to mixed pathologies of aging and showed that tau and not amyloid-β is primarily associated with reduced mtDNAcn. In the posterior cingulate cortex, the association of TDP-43 with low mtDNAcn points to a vulnerability of this region in limbic-predominant age-related TDP-43 encephalopathy. While we found low mtDNAcn in brain regions affected by pathologies, the absence of associations with mtDNA heteroplasmy burden indicates that mtDNA point mutations and small indels are unlikely to be involved in the pathogenesis of late-onset neurodegenerative diseases.
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Affiliation(s)
- Hans-Ulrich Klein
- Center for Translational & Computational Neuroimmunology, Department of Neurology, Columbia University Irving Medical Center, New York, NY 10032 USA
- Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, Columbia University Irving Medical Center, New York, NY 10032 USA
| | - Caroline Trumpff
- Division of Behavioral Medicine, Department of Psychiatry, Columbia University Irving Medical Center, New York, NY 10032 USA
| | - Hyun-Sik Yang
- Center for Alzheimer Research and Treatment, Department of Neurology, Brigham and Women’s Hospital, Boston, MA 02115 USA
| | - Annie J. Lee
- Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, Columbia University Irving Medical Center, New York, NY 10032 USA
| | - Martin Picard
- Division of Behavioral Medicine, Department of Psychiatry, Columbia University Irving Medical Center, New York, NY 10032 USA
- Merritt Center and Columbia Translational Neuroscience Initiative, Department of Neurology, Columbia University Irving Medical Center, New York, NY 10032 USA
| | - David A. Bennett
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL 60612 USA
| | - Philip L. De Jager
- Center for Translational & Computational Neuroimmunology, Department of Neurology, Columbia University Irving Medical Center, New York, NY 10032 USA
- Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, Columbia University Irving Medical Center, New York, NY 10032 USA
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17
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Spadini S, Racchetti G, Adiletta A, Lamanna J, Moro AS, Ferro M, Zimarino V, Malgaroli A. A novel integrated approach to estimate the mitochondrial content of neuronal cells and brain tissues. J Neurosci Methods 2021; 363:109351. [PMID: 34481832 DOI: 10.1016/j.jneumeth.2021.109351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 07/28/2021] [Accepted: 08/31/2021] [Indexed: 10/20/2022]
Abstract
BACKGROUND Mitochondria and their dynamics fuel most cellular processes both in physiological and pathological conditions. In the central nervous system, mitochondria sustain synaptic transmission and plasticity via multiple mechanisms which include their redistribution and/or expansion to higher energy demanding sites, sustaining activity changes and promoting morphological circuit adaptations. NEW METHOD To be able to evaluate changes in mitochondrial number and protein phenotype, we propose a novel methodological approach where the simultaneous analysis of both mitochondrial DNA and protein content is performed on each individual microsample, avoiding non-homogeneous loss of material. RESULTS We validated this method on neuronal-like cells and tissue samples and obtained estimates for the mitochondrial/genomic DNA ratio as well as for the abundance of protein counterparts. When the mitochondrial content per cell was evaluated in different brain areas, our results matched the known regional variation in aerobic-anaerobic metabolism. When long-term potentiation (LTP) was induced on hippocampal neurons, we detected increases in the abundance of mitochondria that correlated with the degree of synaptic enhancement. CONCLUSIONS Our approach can be effectively used to study the mitochondrial content andits changes in different brain cells and tissues.
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Affiliation(s)
- Sara Spadini
- Center for Behavioral Neuroscience and Communication (BNC), Vita-Salute San Raffaele University, Via Olgettina 58, Milan 20132, Italy; Faculty of Psychology, Vita-Salute San Raffaele University, Milan, Italy
| | - Gabriella Racchetti
- Division of Neuroscience, Scientific Institute Ospedale San Raffaele, Milan, Italy
| | - Alice Adiletta
- Center for Behavioral Neuroscience and Communication (BNC), Vita-Salute San Raffaele University, Via Olgettina 58, Milan 20132, Italy; Center for Mind/Brain Sciences (CIMeC), University of Trento, Rovereto, Italy
| | - Jacopo Lamanna
- Center for Behavioral Neuroscience and Communication (BNC), Vita-Salute San Raffaele University, Via Olgettina 58, Milan 20132, Italy; Faculty of Psychology, Vita-Salute San Raffaele University, Milan, Italy
| | - Andrea Stefano Moro
- Center for Behavioral Neuroscience and Communication (BNC), Vita-Salute San Raffaele University, Via Olgettina 58, Milan 20132, Italy; Department of Psychology, Sigmund Freud University, Milan, Italy
| | - Mattia Ferro
- Center for Behavioral Neuroscience and Communication (BNC), Vita-Salute San Raffaele University, Via Olgettina 58, Milan 20132, Italy; Department of Psychology, Sigmund Freud University, Milan, Italy
| | - Vincenzo Zimarino
- Division of Neuroscience, Scientific Institute Ospedale San Raffaele, Milan, Italy
| | - Antonio Malgaroli
- Center for Behavioral Neuroscience and Communication (BNC), Vita-Salute San Raffaele University, Via Olgettina 58, Milan 20132, Italy; Faculty of Psychology, Vita-Salute San Raffaele University, Milan, Italy.
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18
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Picard M. Blood mitochondrial DNA copy number: What are we counting? Mitochondrion 2021; 60:1-11. [PMID: 34157430 PMCID: PMC8464495 DOI: 10.1016/j.mito.2021.06.010] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 06/12/2021] [Accepted: 06/17/2021] [Indexed: 02/06/2023]
Abstract
There is growing scientific interest to develop scalable biological measures that capture mitochondrial (dys)function. Mitochondria have their own genome, the mitochondrial DNA (mtDNA). It has been proposed that the number of mtDNA copies per cell (mtDNA copy number; mtDNAcn) reflects mitochondrial health. The common availability of stored DNA material or existing DNA sequencing data, especially from blood and other easy-to-collect samples, has made its quantification a popular approach in clinical and epidemiological studies. However, the interpretation of mtDNAcn is not univocal, and either a reduction or elevation in mtDNAcn can indicate dysfunction. The major determinants of blood-derived mtDNAcn are the heterogeneous cell type composition of leukocytes and platelet abundance, which can change with time of day, aging, and with disease. Hematopoiesis is a likely driver of blood mtDNAcn. Here we discuss the rationale and available methods to quantify mtDNAcn, the influence of blood cell type variations, and consider important gaps in knowledge that need to be resolved to maximize the scientific value around the investigation of blood mtDNAcn.
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Affiliation(s)
- Martin Picard
- Department of Psychiatry, Division of Behavioral Medicine, Columbia University Irving Medical Center, New York, NY, USA; Department of Neurology, Merritt Center, Columbia Translational Neuroscience Initiative, Columbia University Irving Medical Center, New York, NY, USA; New York State Psychiatric Institute, New York, NY, USA.
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19
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Filograna R, Mennuni M, Alsina D, Larsson NG. Mitochondrial DNA copy number in human disease: the more the better? FEBS Lett 2020; 595:976-1002. [PMID: 33314045 PMCID: PMC8247411 DOI: 10.1002/1873-3468.14021] [Citation(s) in RCA: 204] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/02/2020] [Accepted: 11/26/2020] [Indexed: 12/19/2022]
Abstract
Most of the genetic information has been lost or transferred to the nucleus during the evolution of mitochondria. Nevertheless, mitochondria have retained their own genome that is essential for oxidative phosphorylation (OXPHOS). In mammals, a gene‐dense circular mitochondrial DNA (mtDNA) of about 16.5 kb encodes 13 proteins, which constitute only 1% of the mitochondrial proteome. Mammalian mtDNA is present in thousands of copies per cell and mutations often affect only a fraction of them. Most pathogenic human mtDNA mutations are recessive and only cause OXPHOS defects if present above a certain critical threshold. However, emerging evidence strongly suggests that the proportion of mutated mtDNA copies is not the only determinant of disease but that also the absolute copy number matters. In this review, we critically discuss current knowledge of the role of mtDNA copy number regulation in various types of human diseases, including mitochondrial disorders, neurodegenerative disorders and cancer, and during ageing. We also provide an overview of new exciting therapeutic strategies to directly manipulate mtDNA to restore OXPHOS in mitochondrial diseases.
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Affiliation(s)
- Roberta Filograna
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Mara Mennuni
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - David Alsina
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Nils-Göran Larsson
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
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20
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Arbeithuber B, Hester J, Cremona MA, Stoler N, Zaidi A, Higgins B, Anthony K, Chiaromonte F, Diaz FJ, Makova KD. Age-related accumulation of de novo mitochondrial mutations in mammalian oocytes and somatic tissues. PLoS Biol 2020; 18:e3000745. [PMID: 32667908 PMCID: PMC7363077 DOI: 10.1371/journal.pbio.3000745] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 05/27/2020] [Indexed: 12/21/2022] Open
Abstract
Mutations create genetic variation for other evolutionary forces to operate on and cause numerous genetic diseases. Nevertheless, how de novo mutations arise remains poorly understood. Progress in the area is hindered by the fact that error rates of conventional sequencing technologies (1 in 100 or 1,000 base pairs) are several orders of magnitude higher than de novo mutation rates (1 in 10,000,000 or 100,000,000 base pairs per generation). Moreover, previous analyses of germline de novo mutations examined pedigrees (and not germ cells) and thus were likely affected by selection. Here, we applied highly accurate duplex sequencing to detect low-frequency, de novo mutations in mitochondrial DNA (mtDNA) directly from oocytes and from somatic tissues (brain and muscle) of 36 mice from two independent pedigrees. We found mtDNA mutation frequencies 2- to 3-fold higher in 10-month-old than in 1-month-old mice, demonstrating mutation accumulation during the period of only 9 mo. Mutation frequencies and patterns differed between germline and somatic tissues and among mtDNA regions, suggestive of distinct mutagenesis mechanisms. Additionally, we discovered a more pronounced genetic drift of mitochondrial genetic variants in the germline of older versus younger mice, arguing for mtDNA turnover during oocyte meiotic arrest. Our study deciphered for the first time the intricacies of germline de novo mutagenesis using duplex sequencing directly in oocytes, which provided unprecedented resolution and minimized selection effects present in pedigree studies. Moreover, our work provides important information about the origins and accumulation of mutations with aging/maturation and has implications for delayed reproduction in modern human societies. Furthermore, the duplex sequencing method we optimized for single cells opens avenues for investigating low-frequency mutations in other studies.
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Affiliation(s)
- Barbara Arbeithuber
- Department of Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - James Hester
- Department of Animal Science, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Marzia A. Cremona
- Department of Statistics, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Nicholas Stoler
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Arslan Zaidi
- Department of Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Bonnie Higgins
- Department of Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Kate Anthony
- Department of Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Francesca Chiaromonte
- Department of Statistics, Pennsylvania State University, University Park, Pennsylvania, United States of America
- EMbeDS, Sant’Anna School of Advanced Studies, Pisa, Italy
| | - Francisco J. Diaz
- Department of Animal Science, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Kateryna D. Makova
- Department of Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
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21
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Zhang X, Wang T, Ji J, Wang H, Zhu X, Du P, Zhu Y, Huang Y, Chen W. The distinct spatiotemporal distribution and effect of feed restriction on mtDNA copy number in broilers. Sci Rep 2020; 10:3240. [PMID: 32094402 PMCID: PMC7039872 DOI: 10.1038/s41598-020-60123-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 02/05/2020] [Indexed: 12/22/2022] Open
Abstract
Mitochondrial DNA (mtDNA) copy number reflects the abundance of mitochondria in cells and is dependent on the energy requirements of tissues. We hypothesized that the mtDNA copy number in poultry may change with age and tissue, and feed restriction may affect the growth and health of poultry by changing mtDNA content in a tissue-specific pattern. TaqMan real-time PCR was used to quantify mtDNA copy number using three different segments of the mitochondrial genome (D-loop, ATP6, and ND6) relative to the nuclear single-copy preproglucagon gene (GCG). The effect of sex, age, and dietary restriction (quantitative, energy, and protein restriction) on mtDNA copy number variation in the tissues of broilers was investigated. We found that mtDNA copy number varied among tissues (P < 0.01) and presented a distinct change in spatiotemporal pattern. After hatching, the number of mtDNA copies significantly decreased with age in the liver and increased in muscle tissues, including heart, pectoralis, and leg muscles. Newborn broilers (unfed) and embryos (E 11 and E 17) had similar mtDNA contents in muscle tissues. Among 42 d broilers, females had a higher mtDNA copy number than males in the tissues examined. Feed restriction (8-21 d) significantly reduced the body weight but did not significantly change the mtDNA copy number of 21 d broilers. After three weeks of compensatory growth (22-42 d), only the body weight of broilers with a quantitatively restricted diet remained significantly lower than that of broilers in the control group (P < 0.05), while any type of early feed restriction significantly reduced the mtDNA copy number in muscle tissues of 42 d broilers. In summary, the mtDNA copy number of broilers was regulated in a tissue- and age-specific manner. A similar pattern of spatiotemporal change in response to early feed restriction was found in the mtDNA content of muscle tissues, including cardiac and skeletal muscle, whereas liver mtDNA content changed differently with age and dietary restriction. It seems that early restrictions in feed could effectively lower the mtDNA content in muscle cells to reduce the tissue overload in broilers at 42 d to some degree.
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Affiliation(s)
- Xiangli Zhang
- College of Livestock Husbandry and Veterinary Engineering, Henan Agricultural University, No. 15 Longzi Lake University Campus, Zhengzhou, 450046, P.R. China
| | - Ting Wang
- College of Livestock Husbandry and Veterinary Engineering, Henan Agricultural University, No. 15 Longzi Lake University Campus, Zhengzhou, 450046, P.R. China
| | - Jiefei Ji
- College of Livestock Husbandry and Veterinary Engineering, Henan Agricultural University, No. 15 Longzi Lake University Campus, Zhengzhou, 450046, P.R. China
| | - Huanjie Wang
- College of Livestock Husbandry and Veterinary Engineering, Henan Agricultural University, No. 15 Longzi Lake University Campus, Zhengzhou, 450046, P.R. China
| | - Xinghao Zhu
- College of Livestock Husbandry and Veterinary Engineering, Henan Agricultural University, No. 15 Longzi Lake University Campus, Zhengzhou, 450046, P.R. China
| | - Pengfei Du
- College of Livestock Husbandry and Veterinary Engineering, Henan Agricultural University, No. 15 Longzi Lake University Campus, Zhengzhou, 450046, P.R. China
| | - Yao Zhu
- College of Livestock Husbandry and Veterinary Engineering, Henan Agricultural University, No. 15 Longzi Lake University Campus, Zhengzhou, 450046, P.R. China
| | - Yanqun Huang
- College of Livestock Husbandry and Veterinary Engineering, Henan Agricultural University, No. 15 Longzi Lake University Campus, Zhengzhou, 450046, P.R. China.
| | - Wen Chen
- College of Livestock Husbandry and Veterinary Engineering, Henan Agricultural University, No. 15 Longzi Lake University Campus, Zhengzhou, 450046, P.R. China
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22
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Increased burden of mitochondrial DNA deletions and point mutations in early-onset age-related hearing loss in mitochondrial mutator mice. Exp Gerontol 2019; 125:110675. [PMID: 31344454 DOI: 10.1016/j.exger.2019.110675] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 07/14/2019] [Accepted: 07/20/2019] [Indexed: 11/20/2022]
Abstract
Mitochondrial DNA (mtDNA) mutations are thought to have a causal role in a variety of age-related neurodegenerative diseases, including age-related hearing loss (AHL). In the current study, we investigated the roles of mtDNA deletions and point mutations in AHL in mitochondrial mutator mice (Polgmut/mut) that were backcrossed onto CBA/CaJ mice, a well-established model of late-onset AHL. mtDNA deletions accumulated significantly with age in the inner ears of Polgmut/mut mice, while there were no differences in mtDNA deletion frequencies in the inner ears between 5 and 17 months old Polg+/+ mice or 5 months old Polg+/+ and Polgmut/mut mice. mtDNA deletions also accumulated significantly in the inner ears of CBA/CaJ mice during normal aging. In contrast, 5 months old Polgmut/mut mice displayed a 238-fold increase in mtDNA point mutation frequencies in the inner ears compared to age-matched Polg+/+ mice, but there were no differences in mtDNA point mutation frequencies in the inner ears between 5 and 17 months old Polgmut/mut mice. Seventeen-month-old Polgmut/mut mice also displayed early-onset severe hearing loss associated with a significant reduction in neural output of the cochlea, while age-matched Polg+/+ mice displayed little or no hearing impairment. Consistent with the physiological and mtDNA deletion test result, 17-month-old Polgmut/mut mice displayed a profound loss of spiral ganglion neurons in the cochlea. Thus, our data suggest that a higher burden of mtDNA point mutations from a young age and age-related accumulation of mtDNA deletions likely contribute to early-onset AHL in mitochondrial mutator mice.
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23
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Bigland MJ, Brichta AM, Smith DW. Effects of Ageing on the Mitochondrial Genome in Rat Vestibular Organs. Curr Aging Sci 2019; 11:108-117. [PMID: 30777575 PMCID: PMC6388513 DOI: 10.2174/1874609811666180830143358] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 06/21/2018] [Accepted: 08/01/2018] [Indexed: 01/07/2023]
Abstract
Background: Deterioration in vestibular function occurs with ageing and is linked to age-related falls. Sensory hair cells located in the inner ear vestibular labyrinth are critical to vestibular function. Vestibular hair cells rely predominantly on oxidative phosphorylation (OXPHOS) for ener-gy production and contain numerous mitochondria. Mitochondrial DNA (mtDNA) mutations and perturbed energy production are associated with the ageing process. Objective: We investigated the effects of ageing on mtDNA in vestibular hair and support cells, and vestibular organ gene expression, to better understand mechanisms of age-related vestibular deficits. Methods: Vestibular hair and supporting cell layers were microdissected from young and old rats, and mtDNA was quantified by qPCR. Additionally, vestibular organ gene expression was analysed by microarray and gene set enrichment analyses. Results: In contrast to most other studies, we found no evidence of age-related mtDNA deletion mu-tations. However, we found an increase in abundance of major arc genes near the mtDNA control re-gion. There was also a marked age-related reduction in mtDNA copy number in both cell types. Ves-tibular organ gene expression, gene set enrichment analysis showed the OXPHOS pathway was down regulated in old animals. Conclusion: Given the importance of mtDNA to mitochondrial OXPHOS and hair cell function, our findings suggest the vestibular organs are potentially on the brink of an energy crisis in old animals
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Affiliation(s)
- Mark J Bigland
- Neurobiology of Ageing and Dementia Laboratory, School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW 2308, Australia.,Preclinical Neurobiology Program, Priority Centre for Brain and Mental Health Research, University of Newcastle, Callaghan, NSW 2308, Australia.,Hunter Medical Research Institute, New Lambton Heights, NSW 2305, Australia
| | - Alan M Brichta
- Neurobiology of Ageing and Dementia Laboratory, School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW 2308, Australia.,Preclinical Neurobiology Program, Priority Centre for Brain and Mental Health Research, University of Newcastle, Callaghan, NSW 2308, Australia.,Hunter Medical Research Institute, New Lambton Heights, NSW 2305, Australia
| | - Doug W Smith
- Neurobiology of Ageing and Dementia Laboratory, School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW 2308, Australia.,Preclinical Neurobiology Program, Priority Centre for Brain and Mental Health Research, University of Newcastle, Callaghan, NSW 2308, Australia.,Hunter Medical Research Institute, New Lambton Heights, NSW 2305, Australia
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24
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Sidorova-Darmos E, Sommer R, Eubanks JH. The Role of SIRT3 in the Brain Under Physiological and Pathological Conditions. Front Cell Neurosci 2018; 12:196. [PMID: 30090057 PMCID: PMC6068278 DOI: 10.3389/fncel.2018.00196] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 06/17/2018] [Indexed: 12/22/2022] Open
Abstract
Sirtuin enzymes are a family of highly seven conserved protein deacetylases, namely SIRT1 through SIRT7, whose enzymatic activities require the cofactor nicotinamide adenine dinucleotide (NAD+). Sirtuins reside in different compartments within cells, and their activities have been shown to regulate a number of cellular pathways involved in but not limited to stress management, apoptosis and inflammatory responses. Given the importance of mitochondrial functional state in neurodegenerative conditions, the mitochondrial SIRT3 sirtuin, which is the primary deacetylase within mitochondria, has garnered considerable recent attention. It is now clear that SIRT3 plays a major role in regulating a host of mitochondrial molecular cascades that can contribute to both normal and pathophysiological processes. However, most of the currently available knowledge on SIRT3 stems from studies in non-neuronal cells, and the consequences of the interactions between SIRT3 and its targets in the CNS are only beginning to be elucidated. In this review, we will summarize current advances relating to SIRT3, and explore how its known functions could influence brain physiology.
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Affiliation(s)
- Elena Sidorova-Darmos
- Division of Genetics and Development, Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada.,Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
| | - Rosa Sommer
- Division of Genetics and Development, Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - James H Eubanks
- Division of Genetics and Development, Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada.,Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada.,Department of Surgery (Neurosurgery), University of Toronto, Toronto, ON, Canada
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25
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Kang I, Chu CT, Kaufman BA. The mitochondrial transcription factor TFAM in neurodegeneration: emerging evidence and mechanisms. FEBS Lett 2018; 592:793-811. [PMID: 29364506 PMCID: PMC5851836 DOI: 10.1002/1873-3468.12989] [Citation(s) in RCA: 156] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 01/18/2018] [Accepted: 01/19/2018] [Indexed: 12/30/2022]
Abstract
The mitochondrial transcription factor A, or TFAM, is a mitochondrial DNA (mtDNA)-binding protein essential for genome maintenance. TFAM functions in determining the abundance of the mitochondrial genome by regulating packaging, stability, and replication. More recently, TFAM has been shown to play a central role in the mtDNA stress-mediated inflammatory response. Emerging evidence indicates that decreased mtDNA copy number is associated with several aging-related pathologies; however, little is known about the association of TFAM abundance and disease. In this Review, we evaluate the potential associations of altered TFAM levels or mtDNA copy number with neurodegeneration. We also describe potential mechanisms by which mtDNA replication, transcription initiation, and TFAM-mediated endogenous danger signals may impact mitochondrial homeostasis in Alzheimer, Huntington, Parkinson, and other neurodegenerative diseases.
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Affiliation(s)
- Inhae Kang
- Department of Food Science and Nutrition, Jeju National University, Jeju, Korea
- Division of Cardiology, Vascular Medicine Institute, Department of Medicine Center for Metabolic and Mitochondrial Medicine (C3M), University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Charleen T. Chu
- Department of Pathology, Center for Neuroscience, Pittsburgh Institute for Neurodegenerative Diseases, Conformational Protein Diseases Center, and the McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Brett A. Kaufman
- Division of Cardiology, Vascular Medicine Institute, Department of Medicine Center for Metabolic and Mitochondrial Medicine (C3M), University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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26
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Abstract
Mitochondria play a crucial role in a variety of cellular processes ranging from energy metabolism, generation of reactive oxygen species (ROS) and Ca(2+) handling to stress responses, cell survival and death. Malfunction of the organelle may contribute to the pathogenesis of neuromuscular, cancer, premature aging and cardiovascular diseases (CVD), including myocardial ischemia, cardiomyopathy and heart failure (HF). Mitochondria contain their own genome organized into DNA-protein complexes, called "mitochondrial nucleoids," along with multiprotein machineries, which promote mitochondrial DNA (mtDNA) replication, transcription and repair. Although the mammalian organelle possesses almost all known nuclear DNA repair pathways, including base excision repair, mismatch repair and recombinational repair, the proximity of mtDNA to the main sites of ROS production and the lack of protective histones may result in increased susceptibility to various types of mtDNA damage. These include accumulation of mtDNA point mutations and/or deletions and decreased mtDNA copy number, which will impair mitochondrial function and finally, may lead to CVD including HF.
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Affiliation(s)
- José Marín-García
- The Molecular Cardiology and Neuromuscular Institute, 75 Raritan Avenue, Highland Park, NJ, 08904, USA.
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27
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Révész D, Verhoeven JE, Picard M, Lin J, Sidney S, Epel ES, Penninx BWJH, Puterman E. Associations Between Cellular Aging Markers and Metabolic Syndrome: Findings From the CARDIA Study. J Clin Endocrinol Metab 2018; 103:148-157. [PMID: 29053810 PMCID: PMC5761498 DOI: 10.1210/jc.2017-01625] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 10/13/2017] [Indexed: 12/22/2022]
Abstract
Background Metabolic syndrome (MetS) is thought to promote biological aging, which might lead to cardiovascular and aging-related complications. This large-scale study investigated longitudinal relationships between MetS, its components, and cellular aging markers: leukocyte mitochondrial DNA copy number (mtDNAcn) and telomere length (TL). Methods We included 989 participants from the Coronary Artery Risk Development in Young Adults Study. MtDNAcn [study year (Y) 15, Y25] and TL (Y15, Y20, Y25) were measured via quantitative polymerase chain reaction. MetS components [waist circumference, triglycerides, high-density lipoprotein (HDL) cholesterol, systolic blood pressure, and fasting glucose] were determined (Y15, Y20, Y25). Generalized estimated equation and linear regression models, adjusting for sociodemographics and lifestyle, were used to examine associations between MetS and cellular aging at all time points, baseline MetS and 10-year changes in cellular aging, baseline cellular aging and 10-year changes in MetS, and 10-year changes in MetS and 10-year changes in cellular aging. Results MtDNAcn and TL were negatively associated with age [mtDNAcn unstandardized β (B) = -4.76; P < 0.001; TL B = -51.53; P < 0.001] and positively correlated (r = 0.152; P < 0.001). High triglycerides were associated with low mtDNAcn and low HDL cholesterol with short TL. Greater Y15 waist circumference (B = -7.23; P = 0.05), glucose (B = -13.29; P = 0.001), number of metabolic dysregulations (B = -7.72; P = 0.02), and MetS (B = -28.86; P = 0.006) predicted greater 10-year decrease in mtDNAcn but not TL. The 10-year increase in waist circumference was associated with 10-year telomere attrition (B = -27.61; P = 0.04). Conclusions Our longitudinal data showed that some metabolic dysregulations were associated with mtDNAcn and TL decreases, possibly contributing to accelerated cellular aging but not the converse.
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Affiliation(s)
- Dóra Révész
- Department of Psychiatry, VU University Medical Center, Amsterdam Public Health Research Institute, 1081 BT Amsterdam, The Netherlands
- Department of Epidemiology, GROW School for Oncology and Developmental Biology, Maastricht University, 6200 MD Maastricht, The Netherlands
| | - Josine E. Verhoeven
- Department of Psychiatry, VU University Medical Center, Amsterdam Public Health Research Institute, 1081 BT Amsterdam, The Netherlands
| | - Martin Picard
- Division of Behavioral Medicine, Department of Psychiatry, Department of Neurology and CTNI, College of Physicians and Surgeons, Columbia University Medical Center, New York, New York 10032
| | - Jue Lin
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California 94158
| | - Stephen Sidney
- Kaiser Permanente Division of Research, Oakland, California 94612
| | - Elissa S. Epel
- Department of Psychiatry, University of California San Francisco School of Medicine, San Francisco, California 94143
| | - Brenda W. J. H. Penninx
- Department of Psychiatry, VU University Medical Center, Amsterdam Public Health Research Institute, 1081 BT Amsterdam, The Netherlands
| | - Eli Puterman
- Department of Psychiatry, University of California San Francisco School of Medicine, San Francisco, California 94143
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
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28
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Fries GR, Bauer IE, Scaini G, Wu MJ, Kazimi IF, Valvassori SS, Zunta-Soares G, Walss-Bass C, Soares JC, Quevedo J. Accelerated epigenetic aging and mitochondrial DNA copy number in bipolar disorder. Transl Psychiatry 2017; 7:1283. [PMID: 29225347 PMCID: PMC5802567 DOI: 10.1038/s41398-017-0048-8] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 09/13/2017] [Indexed: 12/14/2022] Open
Abstract
Bipolar disorder (BD) has been previously associated with accelerated aging; yet, the mechanisms underlying this association are largely unknown. The epigenetic clock has been increasingly recognized as a valuable aging marker, although its association with other biological clocks in BD patients and high-risk subjects, such as telomere length and mitochondrial DNA (mtDNA) copy number, has never been investigated. We included 22 patients with BD I, 16 siblings of BD patients, and 20 healthy controls in this analysis. DNA was isolated from peripheral blood and interrogated for genome-wide DNA methylation, mtDNA copy number, and telomere length. DNA methylation age (DNAm age) and accelerated aging were calculated using the Horvath age estimation algorithm in blood and in postmortem brain from BD patients and nonpsychiatric controls using publicly available data. Older BD patients presented significantly accelerated epigenetic aging compared to controls, whereas no difference was detected among the younger subjects. Patients showed higher levels of mtDNA copy number, while no difference was found between controls and siblings. mtDNA significantly correlated with epigenetic age acceleration among older subjects, as well and with global functioning in our sample. Telomere length did not show significant differences between groups, nor did it correlate with epigenetic aging or mtDNA copy number. These results suggest that BD may involve an accelerated epigenetic aging, which might represent a novel target for treating BD and subjects at risk. In particular, our results suggest a complex interplay between biological clocks to determine the accelerated aging and its consequences in BD.
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Affiliation(s)
- Gabriel R Fries
- Translational Psychiatry Program, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, University of Texas Health Science Center at Houston (UTHealth), 1941 East Rd, 77054, Houston, TX, USA
| | - Isabelle E Bauer
- Center of Excellence on Mood Disorders, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA
| | - Giselli Scaini
- Translational Psychiatry Program, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, University of Texas Health Science Center at Houston (UTHealth), 1941 East Rd, 77054, Houston, TX, USA
| | - Mon-Ju Wu
- Center of Excellence on Mood Disorders, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA
| | - Iram F Kazimi
- Center of Excellence on Mood Disorders, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA
| | - Samira S Valvassori
- Laboratory of Neurosciences, Graduate Program in Health Sciences, Health Sciences Unit, University of Southern Santa Catarina (UNESC), Criciúma, SC, Brazil
| | - Giovana Zunta-Soares
- Center of Excellence on Mood Disorders, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA
| | - Consuelo Walss-Bass
- Translational Psychiatry Program, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, University of Texas Health Science Center at Houston (UTHealth), 1941 East Rd, 77054, Houston, TX, USA
- Center of Excellence on Mood Disorders, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA
- Neuroscience Graduate Program, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, USA
| | - Jair C Soares
- Center of Excellence on Mood Disorders, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA
| | - Joao Quevedo
- Translational Psychiatry Program, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, University of Texas Health Science Center at Houston (UTHealth), 1941 East Rd, 77054, Houston, TX, USA.
- Center of Excellence on Mood Disorders, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA.
- Laboratory of Neurosciences, Graduate Program in Health Sciences, Health Sciences Unit, University of Southern Santa Catarina (UNESC), Criciúma, SC, Brazil.
- Neuroscience Graduate Program, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, USA.
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29
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Herbst A, Widjaja K, Nguy B, Lushaj EB, Moore TM, Hevener AL, McKenzie D, Aiken JM, Wanagat J. Digital PCR Quantitation of Muscle Mitochondrial DNA: Age, Fiber Type, and Mutation-Induced Changes. J Gerontol A Biol Sci Med Sci 2017; 72:1327-1333. [PMID: 28460005 DOI: 10.1093/gerona/glx058] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 03/21/2017] [Indexed: 01/07/2023] Open
Abstract
Definitive quantitation of mitochondrial DNA (mtDNA) and mtDNA deletion mutation abundances would help clarify the role of mtDNA instability in aging. To more accurately quantify mtDNA, we applied the emerging technique of digital polymerase chain reaction to individual muscle fibers and muscle homogenates from aged rodents. Individual fiber mtDNA content correlated with fiber type and decreased with age. We adapted a digital polymerase chain reaction deletion assay that was accurate in mixing experiments to a mutation frequency of 0.03% and quantitated an age-induced increase in deletion frequency from rat muscle homogenates. Importantly, the deletion frequency measured in muscle homogenates strongly correlated with electron transport chain-deficient fiber abundance determined by histochemical analyses. These data clarify the temporal accumulation of mtDNA deletions that lead to electron chain-deficient fibers, a process culminating in muscle fiber loss.
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Affiliation(s)
- Allen Herbst
- Department of Agricultural, Food and Nutritional Sciences, University of Alberta, Edmonton, Canada
| | - Kevin Widjaja
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles
| | - Beatrice Nguy
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles
| | - Entela B Lushaj
- Department of Surgery, School of Medicine and Public Health, University of Wisconsin, Madison
| | - Timothy M Moore
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles
| | - Andrea L Hevener
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles
| | - Debbie McKenzie
- Department of Biological Sciences, University of Alberta, Edmonton, Canada
| | - Judd M Aiken
- Department of Agricultural, Food and Nutritional Sciences, University of Alberta, Edmonton, Canada
| | - Jonathan Wanagat
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles
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Lesnefsky EJ, Chen Q, Hoppel CL. Mitochondrial Metabolism in Aging Heart. Circ Res 2017; 118:1593-611. [PMID: 27174952 DOI: 10.1161/circresaha.116.307505] [Citation(s) in RCA: 214] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 04/05/2016] [Indexed: 02/07/2023]
Abstract
Altered mitochondrial metabolism is the underlying basis for the increased sensitivity in the aged heart to stress. The aged heart exhibits impaired metabolic flexibility, with a decreased capacity to oxidize fatty acids and enhanced dependence on glucose metabolism. Aging impairs mitochondrial oxidative phosphorylation, with a greater role played by the mitochondria located between the myofibrils, the interfibrillar mitochondria. With aging, there is a decrease in activity of complexes III and IV, which account for the decrease in respiration. Furthermore, aging decreases mitochondrial content among the myofibrils. The end result is that in the interfibrillar area, there is ≈50% decrease in mitochondrial function, affecting all substrates. The defective mitochondria persist in the aged heart, leading to enhanced oxidant production and oxidative injury and the activation of oxidant signaling for cell death. Aging defects in mitochondria represent new therapeutic targets, whether by manipulation of the mitochondrial proteome, modulation of electron transport, activation of biogenesis or mitophagy, or the regulation of mitochondrial fission and fusion. These mechanisms provide new ways to attenuate cardiac disease in elders by preemptive treatment of age-related defects, in contrast to the treatment of disease-induced dysfunction.
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Affiliation(s)
- Edward J Lesnefsky
- From the Division of Cardiology, Department of Medicine, Pauley Heart Center (E.J.L, Q.C.), Departments of Biochemistry and Molecular Biology and Physiology and Biophsyics (E.J.L.), Virginia Commonwealth University, Richmond, VA (E.J.L., Q.C.); Medical Service, McGuire Veterans Affairs Medical Center, Richmond, VA (E.J.L.); and Departments of Pharmacology (C.L.H.) and Medicine (E.J.L., C.L.H.), Center for Mitochondrial Disease (C.L.H.), Case Western Reserve University, School of Medicine, Cleveland, OH
| | - Qun Chen
- From the Division of Cardiology, Department of Medicine, Pauley Heart Center (E.J.L, Q.C.), Departments of Biochemistry and Molecular Biology and Physiology and Biophsyics (E.J.L.), Virginia Commonwealth University, Richmond, VA (E.J.L., Q.C.); Medical Service, McGuire Veterans Affairs Medical Center, Richmond, VA (E.J.L.); and Departments of Pharmacology (C.L.H.) and Medicine (E.J.L., C.L.H.), Center for Mitochondrial Disease (C.L.H.), Case Western Reserve University, School of Medicine, Cleveland, OH
| | - Charles L Hoppel
- From the Division of Cardiology, Department of Medicine, Pauley Heart Center (E.J.L, Q.C.), Departments of Biochemistry and Molecular Biology and Physiology and Biophsyics (E.J.L.), Virginia Commonwealth University, Richmond, VA (E.J.L., Q.C.); Medical Service, McGuire Veterans Affairs Medical Center, Richmond, VA (E.J.L.); and Departments of Pharmacology (C.L.H.) and Medicine (E.J.L., C.L.H.), Center for Mitochondrial Disease (C.L.H.), Case Western Reserve University, School of Medicine, Cleveland, OH.
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Zole E, Zadinane K, Pliss L, Ranka R. Linkage between mitochondrial genome alterations, telomere length and aging population. Mitochondrial DNA A DNA Mapp Seq Anal 2017; 29:431-438. [PMID: 28340313 DOI: 10.1080/24701394.2017.1303490] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We studied telomere length (TL) and mitochondrial DNA (mtDNA) copy number variations in individuals from Latvian Caucasian population in different age groups. We showed a positive correlation between TL and mtDNA copy number in individuals of up to 90 years of age; however, this correlation was not observed in the 90-100 years age group. While TL shortened with age and mtDNA content decreased with increasing age, in this study it was observed that mtDNA copy number in nonagenarians was slightly higher than in the 60-89 years age group. The presence of heteroplasmy in the mtDNA HVS-I control region did not correlate with TL and mtDNA copy number. TL and mtDNA values also did not differ between mitochondrial haplogroups. In conclusion, while both TL and mtDNA are involved in the aging process and link between these cell components exists, nonagenarians may have differences in senescence-related pathways and systems, which may function as a protective mechanism that allows them to live longer.
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Affiliation(s)
- Egija Zole
- a Latvian Biomedical Research and Study Centre , Riga , Latvia.,b Faculty of Biology , University of Latvia , Riga , Latvia
| | | | - Liana Pliss
- a Latvian Biomedical Research and Study Centre , Riga , Latvia
| | - Renate Ranka
- a Latvian Biomedical Research and Study Centre , Riga , Latvia.,c Riga Stradins University , Riga , Latvia
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Gureev AP, Syromyatnikov MY, Gorbacheva TM, Starkov AA, Popov VN. Methylene blue improves sensorimotor phenotype and decreases anxiety in parallel with activating brain mitochondria biogenesis in mid-age mice. Neurosci Res 2016; 113:19-27. [DOI: 10.1016/j.neures.2016.07.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 07/19/2016] [Accepted: 07/29/2016] [Indexed: 01/31/2023]
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Kamfar S, Alavian SM, Houshmand M, Yadegarazari R, Seifi Zarei B, Khalaj A, Shabab N, Saidijam M. Liver Mitochondrial DNA Copy Number and Deletion Levels May Contribute to Nonalcoholic Fatty Liver Disease Susceptibility. HEPATITIS MONTHLY 2016; 16:e40774. [PMID: 28123441 PMCID: PMC5237470 DOI: 10.5812/hepatmon.40774] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 09/23/2016] [Accepted: 11/05/2016] [Indexed: 12/11/2022]
Abstract
BACKGROUND There is growing evidence that deficiencies observed in the mitochondrial DNA (mtDNA) functions could play an important role in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). We hypothesized that genetic variations in mtDNA could affect the mitochondrial function and contribute to the NAFLD susceptibility. OBJECTIVES In this study, the possible association of the mtDNA copy number and 4,977-bp deletion levels with NAFLD susceptibility in a sample of Iranian population was evaluated. METHODS This case-control study included 43 NAFLD patients and 20 control subjects. Genomic DNA was extracted from fresh liver tissue samples by using a DNA isolation kit. The mtDNA copy number and mtDNA deletion levels were measured by quantitative real-time PCR and multiplex PCR. RESULTS The relative expression of mtDNA copy number was 3.7 fold higher in NAFLD patients than healthy controls (P < 0.0001). The results remained significant after adjustment for age, BMI, and gender (P = 0.02). In addition, the mtDNA copy number was 4.3 (P < 0.0001) and 3.2-fold (P < 0.0001) higher in nonalcoholic fatty liver (NAFL) and non-alcoholic steatohepatitis (NASH) patients than healthy controls, respectively. Finally, the results showed that the 4,977-bp deletion is not detected in any of liver tissue samples obtained from the 20 control subjects whereas 8 out of 43 NAFLD patients (18.6%) showed the 4,977 -bp deletion in their liver tissues (P = 0.039). CONCLUSIONS This study indicated an association between mtDNA content in the liver tissue and NAFLD susceptibility that may be a consequence of compensatory response to the cumulative exposures to oxidative damage.
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Affiliation(s)
- Sharareh Kamfar
- Department of Molecular Medicine and Genetics, School of Medicine, Hamadan University of Medical Sciences, Hamadan, IR Iran
- Research Center for Molecular Medicine, Hamadan University of Medical Sciences, Hamadan, IR Iran
| | - Seyed Moayed Alavian
- Baqiyatallah Research Center for Gastroenterology and Liver Diseases (BRCGL), Baqiyatallah University of Medical Sciences, Tehran, IR Iran
- Middle East Liver Diseases (MELD) Center, Tehran, IR Iran
| | - Massoud Houshmand
- Department of Medical Genetics, National Institute for Genetic Engineering and Biotechnology, Tehran, IR Iran
| | - Reza Yadegarazari
- Shohada Hospital of Harsin, Kermanshah University of Medical Sciences, Kermanshah, IR Iran
| | - Bahram Seifi Zarei
- School of Medicine, Shahid Beheshti Hospital, Hamadan University of Medical Sciences, Hamadan, IR Iran
| | - Alireza Khalaj
- Obesity Treatment Center, Department of Surgery, Shahed University, Tehran, IR Iran
| | - Noshin Shabab
- Research Center for Molecular Medicine, Hamadan University of Medical Sciences, Hamadan, IR Iran
| | - Massoud Saidijam
- Department of Molecular Medicine and Genetics, School of Medicine, Hamadan University of Medical Sciences, Hamadan, IR Iran
- Research Center for Molecular Medicine, Hamadan University of Medical Sciences, Hamadan, IR Iran
- Corresponding Author: Massoud Saidijam, Research Center for Molecular Medicine, Hamadan University of Medical Sciences, Hamadan, IR Iran. Tel: +98-8138380462, Fax: +98-8138380464, E-mail:
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Wachsmuth M, Hübner A, Li M, Madea B, Stoneking M. Age-Related and Heteroplasmy-Related Variation in Human mtDNA Copy Number. PLoS Genet 2016; 12:e1005939. [PMID: 26978189 PMCID: PMC4792396 DOI: 10.1371/journal.pgen.1005939] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 02/24/2016] [Indexed: 12/17/2022] Open
Abstract
The mitochondrial (mt) genome is present in many copies in human cells, and intra-individual variation in mtDNA sequences is known as heteroplasmy. Recent studies found that heteroplasmies are highly tissue-specific, site-specific, and allele-specific, however the functional implications have not been explored. This study investigates variation in mtDNA copy numbers (mtCN) in 12 different tissues obtained at autopsy from 152 individuals (ranging in age from 3 days to 96 years). Three different methods to estimate mtCN were compared: shotgun sequencing (in 4 tissues), capture-enriched sequencing (in 12 tissues) and droplet digital PCR (ddPCR, in 2 tissues). The highest precision in mtCN estimation was achieved using shotgun sequencing data. However, capture-enrichment data provide reliable estimates of relative (albeit not absolute) mtCNs. Comparisons of mtCN from different tissues of the same individual revealed that mtCNs in different tissues are, with few exceptions, uncorrelated. Hence, each tissue of an individual seems to regulate mtCN in a tissue-related rather than an individual-dependent manner. Skeletal muscle (SM) samples showed an age-related decrease in mtCN that was especially pronounced in males, while there was an age-related increase in mtCN for liver (LIV) samples. MtCN in SM samples was significantly negatively correlated with both the total number of heteroplasmic sites and with minor allele frequency (MAF) at two heteroplasmic sites, 408 and 16327. Heteroplasmies at both sites are highly specific for SM, accumulate with aging and are part of functional elements that regulate mtDNA replication. These data support the hypothesis that selection acting on these heteroplasmic sites is reducing mtCN in SM of older individuals.
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Affiliation(s)
- Manja Wachsmuth
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Alexander Hübner
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | | | - Burkhard Madea
- Institut für Rechtsmedizin, Universitätsklinikum Bonn, Bonn, Germany
| | - Mark Stoneking
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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Akhmedov AT, Marín-García J. Mitochondrial DNA maintenance: an appraisal. Mol Cell Biochem 2015; 409:283-305. [DOI: 10.1007/s11010-015-2532-x] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 08/06/2015] [Indexed: 12/13/2022]
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Szklarczyk R, Nooteboom M, Osiewacz HD. Control of mitochondrial integrity in ageing and disease. Philos Trans R Soc Lond B Biol Sci 2015; 369:20130439. [PMID: 24864310 DOI: 10.1098/rstb.2013.0439] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Various molecular and cellular pathways are active in eukaryotes to control the quality and integrity of mitochondria. These pathways are involved in keeping a 'healthy' population of this essential organelle during the lifetime of the organism. Quality control (QC) systems counteract processes that lead to organellar dysfunction manifesting as degenerative diseases and ageing. We discuss disease- and ageing-related pathways involved in mitochondrial QC: mtDNA repair and reorganization, regeneration of oxidized amino acids, refolding and degradation of severely damaged proteins, degradation of whole mitochondria by mitophagy and finally programmed cell death. The control of the integrity of mtDNA and regulation of its expression is essential to remodel single proteins as well as mitochondrial complexes that determine mitochondrial functions. The redundancy of components, such as proteases, and the hierarchies of the QC raise questions about crosstalk between systems and their precise regulation. The understanding of the underlying mechanisms on the genomic, proteomic, organellar and cellular levels holds the key for the development of interventions for mitochondrial dysfunctions, degenerative processes, ageing and age-related diseases resulting from impairments of mitochondria.
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Affiliation(s)
- Radek Szklarczyk
- Centre for Molecular and Biomolecular Informatics, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands Department of Clinical Genetics, Unit Clinical Genomics, Maastricht University Medical Centre, 6200 MD Maastricht, The Netherlands
| | - Marco Nooteboom
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | - Heinz D Osiewacz
- Faculty for Biosciences and Cluster of Excellence 'Macromolecular Complexes', Goethe University, Molecular Developmental Biology, 60438 Frankfurt am Main, Germany
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Kumar RA, Oldenburg DJ, Bendich AJ. Changes in DNA damage, molecular integrity, and copy number for plastid DNA and mitochondrial DNA during maize development. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:6425-39. [PMID: 25261192 PMCID: PMC4246179 DOI: 10.1093/jxb/eru359] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The amount and structural integrity of organellar DNAs change during plant development, although the mechanisms of change are poorly understood. Using PCR-based methods, we quantified DNA damage, molecular integrity, and genome copy number for plastid and mitochondrial DNAs of maize seedlings. A DNA repair assay was also used to assess DNA impediments. During development, DNA damage increased and molecules with impediments that prevented amplification by Taq DNA polymerase increased, with light causing the greatest change. DNA copy number values depended on the assay method, with standard real-time quantitative PCR (qPCR) values exceeding those determined by long-PCR by 100- to 1000-fold. As the organelles develop, their DNAs may be damaged in oxidative environments created by photo-oxidative reactions and photosynthetic/respiratory electron transfer. Some molecules may be repaired, while molecules with unrepaired damage may be degraded to non-functional fragments measured by standard qPCR but not by long-PCR.
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Affiliation(s)
- Rachana A Kumar
- Department of Biology, University of Washington, Seattle, WA 98195-5325, USA
| | - Delene J Oldenburg
- Department of Biology, University of Washington, Seattle, WA 98195-5325, USA
| | - Arnold J Bendich
- Department of Biology, University of Washington, Seattle, WA 98195-5325, USA
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38
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Mitochondrial function and mitochondrial DNA maintenance with advancing age. Biogerontology 2014; 15:417-38. [PMID: 25015781 DOI: 10.1007/s10522-014-9515-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Accepted: 07/01/2014] [Indexed: 12/24/2022]
Abstract
We review the impact of mitochondrial DNA (mtDNA) maintenance and mitochondrial function on the aging process. Mitochondrial function and mtDNA integrity are closely related. In order to create a protective barrier against reactive oxygen and nitrogen species (RONS) attacks and ensure mtDNA integrity, multiple cellular mtDNA copies are packaged together with various proteins in nucleoids. Regulation of antioxidant and RONS balance, DNA base excision repair, and selective degradation of damaged mtDNA copies preserves normal mtDNA quantities. Oxidative damage to mtDNA molecules does not substantially contribute to increased mtDNA mutation frequency; rather, mtDNA replication errors of DNA PolG are the main source of mtDNA mutations. Mitochondrial turnover is the major contributor to maintenance of mtDNA and functionally active mitochondria. Mitochondrial turnover involves mitochondrial biogenesis, mitochondrial dynamics, and selective autophagic removal of dysfunctional mitochondria (i.e., mitophagy). All of these processes exhibit decreased activity during aging and fall under greater nuclear genome control, possibly coincident with the emergence of nuclear genome instability. We suggest that the age-dependent accumulation of mutated mtDNA copies and dysfunctional mitochondria is associated primarily with decreased cellular autophagic and mitophagic activity.
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39
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Mengel-From J, Thinggaard M, Dalgård C, Kyvik KO, Christensen K, Christiansen L. Mitochondrial DNA copy number in peripheral blood cells declines with age and is associated with general health among elderly. Hum Genet 2014; 133:1149-59. [PMID: 24902542 DOI: 10.1007/s00439-014-1458-9] [Citation(s) in RCA: 248] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2013] [Accepted: 05/22/2014] [Indexed: 12/21/2022]
Abstract
The role of the mitochondria in disease, general health and aging has drawn much attention over the years. Several attempts have been made to describe how the numbers of mitochondria correlate with age, although with inconclusive results. In this study, the relative quantity of mitochondrial DNA compared to nuclear DNA, i.e. the mitochondrial DNA copy number, was measured by PCR technology and used as a proxy for the content of mitochondria copies. In 1,067 Danish twins and singletons (18-93 years of age), with the majority being elderly individuals, the estimated mean mitochondrial DNA copy number in peripheral blood cells was similar for those 18-48 years of age [mean relative mtDNA content: 61.0; 95 % CI (52.1; 69.9)], but declined by -0.54 mtDNA 95 % CI (-0.63; -0.45) every year for those older than approximately 50 years of age. However, the longitudinal, yearly decline within an individual was more than twice as steep as observed in the cross-sectional analysis [decline of mtDNA content: -1.27; 95 % CI (-1.71; -0.82)]. Subjects with low mitochondrial DNA copy number had poorer outcomes in terms of cognitive performance, physical strength, self-rated health, and higher all-cause mortality than subjects with high mitochondrial DNA copy number, also when age was controlled for. The copy number mortality association can contribute to the smaller decline in a cross-sectional sample of the population compared to the individual, longitudinal decline. This study suggests that high mitochondrial DNA copy number in blood is associated with better health and survival among elderly.
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Affiliation(s)
- Jonas Mengel-From
- Epidemiology, Biostatistics and Biodemography Unit, The Danish Aging Research Center, The Danish Twin Registry, Institute of Public Health, University of Southern Denmark, J.B. Winsløws Vej 9, 5000, Odense, Denmark,
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40
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Matam K, Shaik NA, Aggarwal S, Diwale S, Banaganapalli B, Al-Aama JY, Elango R, Rao P, Hasan Q. Evidence for the presence of somatic mitochondrial DNA mutations in right atrial appendage tissues of coronary artery disease patients. Mol Genet Genomics 2014; 289:533-40. [DOI: 10.1007/s00438-014-0828-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2013] [Accepted: 02/11/2014] [Indexed: 12/31/2022]
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Bendich AJ. DNA abandonment and the mechanisms of uniparental inheritance of mitochondria and chloroplasts. Chromosome Res 2014; 21:287-96. [PMID: 23681660 DOI: 10.1007/s10577-013-9349-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
For most eukaryotic organisms, the nuclear genomes of both parents are transmitted to the progeny following biparental inheritance. For mitochondria and chloroplasts, however, uniparental inheritance (UPI) is frequently observed. The maternal mode of inheritance for mitochondria in animals can be nearly absolute, suggesting an adaptive advantage for UPI. In other organisms, however, the mode of inheritance for mitochondria and chloroplasts can vary greatly even among strains of a species. Here, I review the data on the transmission of organellar DNA (orgDNA) from parent to progeny and the structure, copy number, and stability of orgDNA molecules. I propose that UPI is an incidental by-product of DNA abandonment, a process that lowers the metabolic cost of orgDNA repair.
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Affiliation(s)
- Arnold J Bendich
- Department of Biology, University of Washington, Seattle, WA 98195, USA.
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42
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Kazachkova N, Ramos A, Santos C, Lima M. Mitochondrial DNA damage patterns and aging: revising the evidences for humans and mice. Aging Dis 2013; 4:337-50. [PMID: 24307967 DOI: 10.14336/ad.2013.0400337] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 09/04/2013] [Accepted: 09/06/2013] [Indexed: 01/07/2023] Open
Abstract
A significant body of work, accumulated over the years, strongly suggests that damage in mitochondrial DNA (mtDNA) contributes to aging in humans. Contradictory results, however, are reported in the literature, with some studies failing to provide support to this hypothesis. With the purpose of further understanding the aging process, several models, among which mouse models, have been frequently used. Although important affinities are recognized between humans and mice, differences on what concerns physiological properties, disease pathogenesis as well as life-history exist between the two; the extent to which such differences limit the translation, from mice to humans, of insights on the association between mtDNA damage and aging remains to be established. In this paper we revise the studies that analyze the association between patterns of mtDNA damage and aging, investigating putative alterations in mtDNA copy number as well as accumulation of deletions and of point mutations. Reports from the literature do not allow the establishment of a clear association between mtDNA copy number and age, either in humans or in mice. Further analysis, using a wide spectrum of tissues and a high number of individuals would be necessary to elucidate this pattern. Likewise humans, mice demonstrated a clear pattern of age-dependent and tissue-specific accumulation of mtDNA deletions. Deletions increase with age, and the highest amount of deletions has been observed in brain tissues both in humans and mice. On the other hand, mtDNA point mutations accumulation has been clearly associated with age in humans, but not in mice. Although further studies, using the same methodologies and targeting a larger number of samples would be mandatory to draw definitive conclusions, the revision of the available data raises concerns on the ability of mouse models to mimic the mtDNA damage patterns of humans, a fact with implications not only for the study of the aging process, but also for investigations of other processes in which mtDNA dysfunction is a hallmark, such as neurodegeneration.
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Affiliation(s)
- Nadiya Kazachkova
- Centre of Research in Natural Resources (CIRN), Department of Biology, University of the Azores, Ponta Delgada, Portugal ; Institute for Molecular and Cell Biology (IBMC), University of Porto, Porto, Portugal
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Zhang SB, Maguire D, Zhang M, Zhang Z, Zhang A, Yin L, Zhang L, Huang L, Vidyasagar S, Swarts S, Okunieff P. The murine common deletion: mitochondrial DNA 3,860-bp deletion after irradiation. Radiat Res 2013; 180:407-13. [PMID: 24059680 DOI: 10.1667/rr3373.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
This study demonstrates that mice, similar to humans, have a common mitochondrial DNA deletion (3,860 bp) that encodes 5 transfer RNA genes and 5 polypeptide genes that is related to aging, tissue type and radiotoxicity. Our research indicates that the deletion ratio in the liver was significantly higher than in the brain and gut tissues of 8-month-old mice, as compared to 8-week-old mice. Our results also demonstrate that tissue type, oxidative metabolic capacity and radiosensitivity influence the 3,860-bp deletion level. Therefore, this 3,860-bp deletion content may serve as a biomarker of aging and oxidative damage in mice.
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Affiliation(s)
- Steven B Zhang
- Department of Radiation Oncology, University of Florida, Cancer and Genetics Research Complex, Gainesville, Florida 32610
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Pohjoismäki JLO, Krüger M, Al-Furoukh N, Lagerstedt A, Karhunen PJ, Braun T. Postnatal cardiomyocyte growth and mitochondrial reorganization cause multiple changes in the proteome of human cardiomyocytes. MOLECULAR BIOSYSTEMS 2013; 9:1210-9. [PMID: 23459711 DOI: 10.1039/c3mb25556e] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Fetal (fCM) and adult cardiomyocytes (aCM) significantly differ from each other both by structure and biochemical properties. aCM own a higher mitochondrial mass compared to fCM due to increased energy demand and show a greater density and higher degree of structural organization of myofibrils. The energy metabolism in aCM relies virtually completely on β-oxidation of fatty acids while fCM use carbohydrates. Rewinding of the aCM phenotype (de-differentiation) arises frequently in diseased hearts spurring questions about its functional relevance and the extent of de-differentiation. Yet, surprisingly little is known about the changes in the human proteome occurring during maturation of fCM to aCM. Here, we examined differences between human fetal and adult hearts resulting in the quantification of 3500 proteins. Moreover, we analyzed mitochondrial proteomes from both stages to obtain more detailed insight into underlying biochemical differences. We found that the majority of changes between fCM and aCM were attributed to growth and maturation of cardiomyocytes. As expected, adult hearts showed higher mitochondrial mass and expressed increased levels of proteins involved in energy metabolism but relatively lower copy numbers of mitochondrial DNA (mtDNA) per total cell volume. We uncovered that the TFAM/mtDNA ratio was kept constant during postnatal development despite a significant increase of mitochondrial protein per mtDNA in adult mitochondria, which revises previous concepts.
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Affiliation(s)
- Jaakko L O Pohjoismäki
- Department of Cardiac Development and Remodelling, Max-Planck-Institute for Heart and Lung Research, Ludwigstrasse 43, 61231 Bad Nauheim, Germany.
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Gene expression deregulation in postnatal skeletal muscle of TK2 deficient mice reveals a lower pool of proliferating myogenic progenitor cells. PLoS One 2013; 8:e53698. [PMID: 23341978 PMCID: PMC3544874 DOI: 10.1371/journal.pone.0053698] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Accepted: 12/03/2012] [Indexed: 01/07/2023] Open
Abstract
Loss of thymidine kinase 2 (TK2) causes a heterogeneous myopathic form of mitochondrial DNA (mtDNA) depletion syndrome (MDS) in humans that predominantly affects skeletal muscle tissue. In mice, TK2 deficiency also affects several tissues in addition to skeletal muscle, including brain, heart, adipose tissue, kidneys and causes death about 3 weeks after birth. We analysed skeletal muscle and heart muscle tissues of Tk2 knockout mice at postnatal development phase and observed that TK2 deficient pups grew slower and their skeletal muscles appeared significantly underdeveloped, whereas heart was close to normal in size. Both tissues showed mtDNA depletion and mitochondria with altered ultrastructure, as revealed by transmission electron microscopy. Gene expression microarray analysis showed a strong down-regulation of genes involved in cell cycle and cell proliferation in both tissues, suggesting a lower pool of undifferentiated proliferating cells. Analysis of isolated primary myoblasts from Tk2 knockout mice showed slow proliferation, less ability to differentiate and signs of premature senescence, even in absence of mtDNA depletion. Our data demonstrate that TK2 deficiency disturbs myogenic progenitor cells function in postnatal skeletal muscle and we propose this as one of the causes of underdeveloped phenotype and myopathic characteristic of the TK2 deficient mice, in addition to the progressive mtDNA depletion, mitochondrial damage and respiratory chain deficiency in post-mitotic differentiated tissue.
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Inheritance of mitochondrial DNA in serially recloned pigs by somatic cell nuclear transfer (SCNT). Biochem Biophys Res Commun 2012; 424:765-70. [PMID: 22809505 DOI: 10.1016/j.bbrc.2012.07.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 07/07/2012] [Indexed: 11/23/2022]
Abstract
Somatic cell nuclear transfer (SCNT) has been established for the transmission of specific nuclear DNA. However, the fate of donor mitochondrial DNA (mtDNA) remains unclear. Here, we examined the fate of donor mtDNA in recloned pigs through third generations. Fibroblasts of recloned pigs were obtained from offspring of each generation produced by fusion of cultured fibroblasts from a Minnesota miniature pig (MMP) into enucleated oocytes of a Landrace pig. The D-loop regions from the mtDNA of donor and recipient differ at nucleotide sequence positions 16050 (A→T), 16062 (T→C), and 16135 (G→A). In order to determine the fate of donor mtDNA in recloned pigs, we analyzed the D-loop region of the donor's mtDNA by allele-specific PCR (AS-PCR) and real-time PCR. Donor mtDNA was successfully detected in all recloned offspring (F1, F2, and F3). These results indicate that heteroplasmy that originate from donor and recipient mtDNA is maintained in recloned pigs, resulting from SCNT, unlike natural reproduction.
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Schmitt K, Grimm A, Kazmierczak A, Strosznajder JB, Götz J, Eckert A. Insights into mitochondrial dysfunction: aging, amyloid-β, and tau-A deleterious trio. Antioxid Redox Signal 2012; 16:1456-66. [PMID: 22117646 DOI: 10.1089/ars.2011.4400] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
SIGNIFICANCE Alzheimer's disease (AD) is an age-related progressive neurodegenerative disorder mainly affecting elderly individuals. The pathology of AD is characterized by amyloid plaques (aggregates of amyloid-β [Aβ]) and neurofibrillary tangles (aggregates of tau), but the mechanisms underlying this dysfunction are still partially unclear. RECENT ADVANCES A growing body of evidence supports mitochondrial dysfunction as a prominent and early, chronic oxidative stress-associated event that contributes to synaptic abnormalities and, ultimately, selective neuronal degeneration in AD. CRITICAL ISSUES In this review, we discuss on the one hand whether mitochondrial decline observed in brain aging is a determinant event in the onset of AD and on the other hand the close interrelationship of this organelle with Aβ and tau in the pathogenic process underlying AD. Moreover, we summarize evidence from aging and Alzheimer models showing that the harmful trio "aging, Aβ, and tau protein" triggers mitochondrial dysfunction through a number of pathways, such as impairment of oxidative phosphorylation (OXPHOS), elevation of reactive oxygen species production, and interaction with mitochondrial proteins, contributing to the development and progression of the disease. FUTURE DIRECTIONS The aging process may weaken the mitochondrial OXPHOS system in a more general way over many years providing a basis for the specific and destructive effects of Aβ and tau. Establishing strategies involving efforts to protect cells at the mitochondrial level by stabilizing or restoring mitochondrial function and energy homeostasis appears to be challenging, but very promising route on the horizon.
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Affiliation(s)
- Karen Schmitt
- Neurobiology Laboratory for Brain Aging and Mental Health, Psychiatric University Clinics, University of Basel, Basel, Switzerland
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Oxidative stress, mitochondrial dysfunction, and aging. JOURNAL OF SIGNAL TRANSDUCTION 2011; 2012:646354. [PMID: 21977319 PMCID: PMC3184498 DOI: 10.1155/2012/646354] [Citation(s) in RCA: 576] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/15/2011] [Accepted: 08/03/2011] [Indexed: 12/31/2022]
Abstract
Aging is an intricate phenomenon characterized by progressive decline in physiological functions and increase in mortality that is often accompanied by many pathological diseases. Although aging is almost universally conserved among all organisms, the underlying molecular mechanisms of aging remain largely elusive. Many theories of aging have been proposed, including the free-radical and mitochondrial theories of aging. Both theories speculate that cumulative damage to mitochondria and mitochondrial DNA (mtDNA) caused by reactive oxygen species (ROS) is one of the causes of aging. Oxidative damage affects replication and transcription of mtDNA and results in a decline in mitochondrial function which in turn leads to enhanced ROS production and further damage to mtDNA. In this paper, we will present the current understanding of the interplay between ROS and mitochondria and will discuss their potential impact on aging and age-related diseases.
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Hartmann N, Reichwald K, Wittig I, Dröse S, Schmeisser S, Lück C, Hahn C, Graf M, Gausmann U, Terzibasi E, Cellerino A, Ristow M, Brandt U, Platzer M, Englert C. Mitochondrial DNA copy number and function decrease with age in the short-lived fish Nothobranchius furzeri. Aging Cell 2011; 10:824-31. [PMID: 21624037 DOI: 10.1111/j.1474-9726.2011.00723.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Among vertebrates that can be kept in captivity, the annual fish Nothobranchius furzeri possesses the shortest known lifespan. It also shows typical signs of aging and is therefore an ideal model to assess the role of different physiological and environmental parameters on aging and lifespan determination. Here, we used Nothobranchius furzeri to study whether aging is associated with mitochondrial DNA (mtDNA) alterations and changes in mitochondrial function. We sequenced the complete mitochondrial genome of N. furzeri and found an extended control region. Large-scale mtDNA deletions have been frequently described to accumulate in other organisms with age, but there was no evidence for the presence of detectable age-related mtDNA deletions in N. furzeri. However, mtDNA copy number significantly decreased with age in skeletal muscle, brain, liver, skin and dorsal fin. Consistent with this finding, expression of Pgc-1α that encodes a transcriptional coactivator of mitochondrial biogenesis and expression of Tfam and mtSsbp both encoding mtDNA binding factors was downregulated with age. The investigation of possible changes in mitochondrial function revealed that the content of respiratory chain complexes III and IV was reduced in skeletal muscle with age. In addition, ADP-stimulated and succinate-dependent respiration was decreased in mitochondria of old fish. These findings suggest that despite the short lifespan, aging in N. furzeri is associated with a decline in mtDNA copy number, the downregulation of mtDNA-associated genes and an impairment of mitochondrial function.
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MESH Headings
- Aging/genetics
- Aging/metabolism
- Aging/physiology
- Animals
- Cell Respiration
- Cyprinodontiformes/genetics
- Cyprinodontiformes/metabolism
- Cyprinodontiformes/physiology
- DNA Copy Number Variations
- DNA, Mitochondrial/analysis
- DNA, Mitochondrial/genetics
- Electrophoresis, Gel, Two-Dimensional
- Gene Expression Regulation, Developmental
- Genome, Mitochondrial
- Longevity
- Mitochondria/genetics
- Mitochondria/metabolism
- Mitochondria/physiology
- Mitochondrial Proteins/genetics
- Mitochondrial Proteins/metabolism
- Models, Theoretical
- Muscle, Skeletal/cytology
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/physiology
- Transcription Factors/genetics
- Transcription Factors/metabolism
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Affiliation(s)
- Nils Hartmann
- Department of Molecular Genetics, Leibniz Institute for Age Research-Fritz Lipmann Institute (FLI), Beutenbergstrasse 11, Jena, Germany.
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Fuke S, Kubota-Sakashita M, Kasahara T, Shigeyoshi Y, Kato T. Regional variation in mitochondrial DNA copy number in mouse brain. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1807:270-4. [PMID: 21145305 DOI: 10.1016/j.bbabio.2010.11.016] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 11/10/2010] [Accepted: 11/30/2010] [Indexed: 11/17/2022]
Abstract
Mitochondria have their own DNA (mitochondrial DNA [mtDNA]). Although mtDNA copy number is dependent on tissues and its decrease is associated with various neuromuscular diseases, detailed distribution of mtDNA copies in the brain remains uncertain. Using real-time quantitative PCR assay, we examined regional variation in mtDNA copy number in 39 brain regions of male mice. A significant regional difference in mtDNA copy number was observed (P<4.8×10(-35)). High levels of mtDNA copies were found in the ventral tegmental area and substantia nigra, two major nuclei containing dopaminergic neurons. In contrast, cerebellar vermis and lobes had significantly lower copy numbers than other regions. Hippocampal dentate gyrus also had a relatively low mtDNA copy number. This study is the first quantitative analysis of regional variation in mtDNA copy number in mouse brain. Our findings are important for the physiological and pathophysiological studies of mtDNA in the brain.
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Affiliation(s)
- Satoshi Fuke
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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