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Li F, Xiang R, Liu Y, Hu G, Jiang Q, Jia T. Approaches and challenges in identifying, quantifying, and manipulating dynamic mitochondrial genome variations. Cell Signal 2024; 117:111123. [PMID: 38417637 DOI: 10.1016/j.cellsig.2024.111123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 02/14/2024] [Accepted: 02/25/2024] [Indexed: 03/01/2024]
Abstract
Mitochondria, the cellular powerhouses, possess their own unique genetic system, including replication, transcription, and translation. Studying these processes is crucial for comprehending mitochondrial disorders, energy production, and their related diseases. Over the past decades, various approaches have been applied in detecting and quantifying mitochondrial genome variations with also the purpose of manipulation of mitochondria or mitochondrial genome for therapeutics. Understanding the scope and limitations of above strategies is not only fundamental to the understanding of basic biology but also critical for exploring disease-related novel target(s), as well to develop innovative therapies. Here, this review provides an overview of different tools and techniques for accurate mitochondrial genome variations identification, quantification, and discuss novel strategies for the manipulation of mitochondria to develop innovative therapeutic interventions, through combining the insights gained from the study of mitochondrial genetics with ongoing single cell omics combined with advanced single molecular tools.
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Affiliation(s)
- Fei Li
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Run Xiang
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China; Department of Thoracic Surgery, Sichuan Clinical Research Center for Cancer, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, Affiliated Cancer Hospital of University of Electronic Science and Technology of China, Chengdu, China
| | - Yue Liu
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Guoliang Hu
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China; Department of Thoracic Surgery, Sichuan Clinical Research Center for Cancer, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, Affiliated Cancer Hospital of University of Electronic Science and Technology of China, Chengdu, China
| | - Quanbo Jiang
- Light, Nanomaterials, Nanotechnologies (L2n) Laboratory, CNRS EMR 7004, University of Technology of Troyes, 12 rue Marie Curie, 10004 Troyes, France
| | - Tao Jia
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China; CNRS-UMR9187, INSERM U1196, PSL-Research University, 91405 Orsay, France; CNRS-UMR9187, INSERM U1196, Université Paris Saclay, 91405 Orsay, France.
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Tímermans A, Otero F, Garrido M, Gosálvez J, Johnston S, Fernández JL. The relationship between sperm nuclear DNA fragmentation, mitochondrial DNA fragmentation, and copy number in normal and abnormal human ejaculates. Andrology 2024; 12:870-880. [PMID: 37786274 DOI: 10.1111/andr.13539] [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: 07/17/2023] [Revised: 09/19/2023] [Accepted: 09/20/2023] [Indexed: 10/04/2023]
Abstract
BACKGROUND While it is common to clinically evaluate sperm nuclear DNA fragmentation, less attention has been given to sperm mitochondrial DNA. Recently, a digital PCR assay has allowed accurate estimation of the proportion of fragmented mtDNA molecules and relative copy number. OBJECTIVES To determine the correlation of classical sperm parameters, average mtDNA copies per spermatozoon and the level of mtDNA fragmentation (SDF-mtDNA) to that of nuclear DNA fragmentation (SDF-nDNA), measured as the proportion of global, single-strand DNA (SDF-SSBs) and double-strand DNA breaks (SDF-DSBs). To determine whether the level of nuclear and mitochondrial DNA fragmentation and/or copy number can differentiate normozoospermic from non-normozoospermic samples. MATERIALS AND METHODS Ejaculates from 29 normozoospermic and 43 non-normozoospermic were evaluated. SDF was determined using the sperm chromatin dispersion assay. mtDNA copy number and SDF-mtDNA were analyzed using digital PCR assays. RESULTS Relative mtDNA copy increased as sperm concentration or motility decreased, or abnormal morphology increased. Unlike SDF-mtDNA, mtDNA copy number was not correlated with SDF-nDNA. SDF-mtDNA increased as the concentration or proportion of non-vital sperm increased; the higher the mtDNA copy number, the lower the level of fragmentation. Non-normozoospermic samples showed double the level of SDF-nDNA compared to normozoospermic (median 25.00 vs. 13.67). mtDNA copy number per spermatozoon was 3× higher in non-normozoospermic ejaculates (median 16.06 vs. 4.99). Although logistic regression revealed SDF-Global and mtDNA copy number as independent risk factors for non-normozoospermia, when SDF-Global and mtDNA copy number were combined, ROC curve analysis resulted in an even stronger discriminatory ability for predicting the probability of non-normozoospermia (AUC = 0.85, 95% CI 0.76-0.94, p < 0.001). CONCLUSION High-quality ejaculates show lower nuclear SDF and retain less mtDNA copies, with approximately half of them fragmented, so that the absolute number of non-fragmented mtDNA molecules per spermatozoon is extremely low.
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Affiliation(s)
- Ana Tímermans
- INIBIC-Complexo Hospitalario Universitario A Coruña (CHUAC), Spain
- Laboratory of Molecular Genetics and Radiobiology, Centro Oncológico de Galicia, Doctor Camilo Veiras, Spain
| | - Fátima Otero
- INIBIC-Complexo Hospitalario Universitario A Coruña (CHUAC), Spain
- Laboratory of Molecular Genetics and Radiobiology, Centro Oncológico de Galicia, Doctor Camilo Veiras, Spain
| | - Manuel Garrido
- Complexo Hospitalario Universitario A Coruña (CHUAC), Clinical Analysis Service, Spain
| | - Jaime Gosálvez
- Genetics Unit, Facultad de Biología, Universidad Autónoma de Madrid, Spain
| | - Stephen Johnston
- School of Environment, The University of Queensland, Gatton, Australia
- School of Veterinary Science, The University of Queensland, Gatton, Gatton, Australia
| | - José Luis Fernández
- INIBIC-Complexo Hospitalario Universitario A Coruña (CHUAC), Spain
- Laboratory of Molecular Genetics and Radiobiology, Centro Oncológico de Galicia, Doctor Camilo Veiras, Spain
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Sanyal D, Arya D, Nishi K, Balasinor N, Singh D. Clinical Utility of Sperm Function Tests in Predicting Male Fertility: A Systematic Review. Reprod Sci 2024; 31:863-882. [PMID: 38012524 DOI: 10.1007/s43032-023-01405-7] [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: 09/11/2023] [Accepted: 11/06/2023] [Indexed: 11/29/2023]
Abstract
Routine semen analysis provides considerable information regarding sperm parameters; however, it is not solely adequate to predict male fertility potential. In the past two decades, several advance sperm function tests have been developed. The present systematic review intends to assess the clinical utility of available advance sperm function tests in predicting the male fertility potential. A systematic literature search was conducted as per PRISMA guidelines using PubMed, MEDLINE, Google Scholar, and Cochrane Library. Different keywords either singly or in combination were used to retrieve the relevant articles related to sperm function tests, male fertility, and pregnancy outcomes. A total of 5169 articles were obtained, out of which 110 meeting the selection criteria were included in this review. The majorly investigated sperm function tests are hypo-osmotic swelling test, acrosome reaction test, sperm capacitation test, hemizona binding assay, sperm DNA fragmentation test, seminal reactive oxygen species test, mitochondrial dysfunction tests, antisperm antibody test, nuclear chromatin de-condensation (NCD) test, etc. The different advance sperm function tests analyse different aspects of sperm function. Hence, any one test may not be helpful to appropriately predict the male fertility potential. Currently, the unavailability of high-quality clinical data, robust thresholds, complex protocols, high cost, etc., are the limiting factors and prohibiting current sperm function tests to reach the clinics. Further multi-centric research efforts are required to fulfil the existing lacunas and pave the way for these tests to be introduced into the clinics.
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Affiliation(s)
- Debarati Sanyal
- Department of Neuroendocrinology, ICMR-National Institute for Research in Reproductive and Child Health, Parel, Mumbai, 400012, India
| | - Deepshikha Arya
- Department of Neuroendocrinology, ICMR-National Institute for Research in Reproductive and Child Health, Parel, Mumbai, 400012, India
| | - Kumari Nishi
- Department of Neuroendocrinology, ICMR-National Institute for Research in Reproductive and Child Health, Parel, Mumbai, 400012, India
| | - Nafisa Balasinor
- Department of Neuroendocrinology, ICMR-National Institute for Research in Reproductive and Child Health, Parel, Mumbai, 400012, India.
| | - Dipty Singh
- Department of Neuroendocrinology, ICMR-National Institute for Research in Reproductive and Child Health, Parel, Mumbai, 400012, India.
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Emerging methods for and novel insights gained by absolute quantification of mitochondrial DNA copy number and its clinical applications. Pharmacol Ther 2021; 232:107995. [PMID: 34592204 DOI: 10.1016/j.pharmthera.2021.107995] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 08/26/2021] [Accepted: 09/01/2021] [Indexed: 02/07/2023]
Abstract
The past thirty years have seen a surge in interest in pathophysiological roles of mitochondria, and the accurate quantification of mitochondrial DNA copy number (mCN) in cells and tissue samples is a fundamental aspect of assessing changes in mitochondrial health and biogenesis. Quantification of mCN between studies is surprisingly variable due to a combination of physiological variability and diverse protocols being used to measure this endpoint. The advent of novel methods to quantify nucleic acids like digital polymerase chain reaction (dPCR) and high throughput sequencing offer the ability to measure absolute values of mCN. We conducted an in-depth survey of articles published between 1969 -- 2020 to create an overview of mCN values, to assess consensus values of tissue-specific mCN, and to evaluate consistency between methods of assessing mCN. We identify best practices for methods used to assess mCN, and we address the impact of using specific loci on the mitochondrial genome to determine mCN. Current data suggest that clinical measurement of mCN can provide diagnostic and prognostic value in a range of diseases and health conditions, with emphasis on cancer and cardiovascular disease, and the advent of means to measure absolute mCN should improve future clinical applications of mCN measurements.
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Chiang S, Braidy N, Maleki S, Lal S, Richardson DR, Huang MLH. Mechanisms of impaired mitochondrial homeostasis and NAD + metabolism in a model of mitochondrial heart disease exhibiting redox active iron accumulation. Redox Biol 2021; 46:102038. [PMID: 34416478 PMCID: PMC8379503 DOI: 10.1016/j.redox.2021.102038] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/22/2021] [Accepted: 06/05/2021] [Indexed: 01/18/2023] Open
Abstract
Due to the high redox activity of the mitochondrion, this organelle can suffer oxidative stress. To manage energy demands while minimizing redox stress, mitochondrial homeostasis is maintained by the dynamic processes of mitochondrial biogenesis, mitochondrial network dynamics (fusion/fission), and mitochondrial clearance by mitophagy. Friedreich's ataxia (FA) is a mitochondrial disease resulting in a fatal hypertrophic cardiomyopathy due to the deficiency of the mitochondrial protein, frataxin. Our previous studies identified defective mitochondrial iron metabolism and oxidative stress potentiating cardiac pathology in FA. However, how these factors alter mitochondrial homeostasis remains uncharacterized in FA cardiomyopathy. This investigation examined the muscle creatine kinase conditional frataxin knockout mouse, which closely mimics FA cardiomyopathy, to dissect the mechanisms of dysfunctional mitochondrial homeostasis. Dysfunction of key mitochondrial homeostatic mechanisms were elucidated in the knockout hearts relative to wild-type littermates, namely: (1) mitochondrial proliferation with condensed cristae; (2) impaired NAD+ metabolism due to perturbations in Sirt1 activity and NAD+ salvage; (3) increased mitochondrial biogenesis, fusion and fission; and (4) mitochondrial accumulation of Pink1/Parkin with increased autophagic/mitophagic flux. Immunohistochemistry of FA patients' heart confirmed significantly enhanced expression of markers of mitochondrial biogenesis, fusion/fission and autophagy. These novel findings demonstrate cardiac frataxin-deficiency results in significant changes to metabolic mechanisms critical for mitochondrial homeostasis. This mechanistic dissection provides critical insight, offering the potential for maintaining mitochondrial homeostasis in FA and potentially other cardio-degenerative diseases by implementing innovative treatments targeting mitochondrial homeostasis and NAD+ metabolism.
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Affiliation(s)
- Shannon Chiang
- Molecular Pharmacology and Pathology Program, Department of Pathology, University of Sydney, NSW, 2006, Australia
| | - Nady Braidy
- Centre for Healthy Brain Ageing, University of New South Wales, NSW, 2052, Australia
| | - Sanaz Maleki
- Department of Pathology, University of Sydney, NSW, 2006, Australia
| | - Sean Lal
- School of Medical Sciences, University of Sydney, NSW, 2006, Australia; Division of Cardiology, Royal Prince Alfred Hospital, Sydney, NSW, 2050, Australia
| | - Des R Richardson
- Molecular Pharmacology and Pathology Program, Department of Pathology, University of Sydney, NSW, 2006, Australia; Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan; Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, Queensland, Australia.
| | - Michael L-H Huang
- Molecular Pharmacology and Pathology Program, Department of Pathology, University of Sydney, NSW, 2006, Australia; School of Medical Sciences, University of Sydney, NSW, 2006, Australia.
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Mosquera A, Guillén R, Otero F, Rego-Pérez I, Blanco FJ, Fernández JL. Design of a digital-PCR assay to quantify fragmented human mitochondrial DNA. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2021; 62:364-373. [PMID: 34115400 DOI: 10.1002/em.22449] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 06/02/2021] [Accepted: 06/03/2021] [Indexed: 06/12/2023]
Abstract
Digital PCR (dPCR) has been adapted to quantify the proportion of mitochondrial DNA (mtDNA) molecules without and with double-strand DNA breaks (DSBs). This is based on a break-apart approach of two differentially labeled target sequences distantly located in the circular DNA molecule. When the two targets amplify in separated reaction partitions, the original mtDNA molecule should be fragmented by two DSBs at least, each in a different segment between targets. When both targets amplify in the same partition, it must correspond to a circular or linear mtDNA molecule. These two possibilities may be distinguished through a restriction endonuclease (RE) induced unique DSB within a DNA segment between the targets. After RE-digestion, separation of both target signals in different partitions must indicate the presence of a previous linear mtDNA molecule. Otherwise, joint amplification in the same partition would correspond to an initial circular mtDNA that has been linearized by the endonuclease. The procedure was validated by assaying different proportions of mtDNA fragmented by in vitro digestion with REs, evidencing a perfect accordance between the expected theoretical values and dPCR quantification. Samples from peripheral blood cells, cellular and extracellular DNA from the U2OS cell line, as well as cells incubated with ethidium bromide to induce mtDNA depletion, were evaluated. The technique may be of interest to complement the studies of mtDNA in relation to aging and human disease, as well as to assess possible adverse effects of certain drugs that could be related to affectation of mtDNA.
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Affiliation(s)
- Alejandro Mosquera
- Genetics Unit, INIBIC-Complexo Hospitalario Universitario A Coruña (CHUAC), A Coruña, Spain
| | - Rebeca Guillén
- Genetics Unit, INIBIC-Complexo Hospitalario Universitario A Coruña (CHUAC), A Coruña, Spain
- Centro Oncológico de Galicia, Laboratory of Genetics and Radiobiology, A Coruña, Spain
| | - Fátima Otero
- Genetics Unit, INIBIC-Complexo Hospitalario Universitario A Coruña (CHUAC), A Coruña, Spain
- Centro Oncológico de Galicia, Laboratory of Genetics and Radiobiology, A Coruña, Spain
| | - Ignacio Rego-Pérez
- Rheumatology Division, INIBIC-Complexo Hospitalario Universitario A Coruña (CHUAC), A Coruña, Spain
| | - Francisco J Blanco
- Rheumatology Division, INIBIC-Complexo Hospitalario Universitario A Coruña (CHUAC), A Coruña, Spain
| | - José Luis Fernández
- Genetics Unit, INIBIC-Complexo Hospitalario Universitario A Coruña (CHUAC), A Coruña, Spain
- Centro Oncológico de Galicia, Laboratory of Genetics and Radiobiology, A Coruña, Spain
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A differentiated Ca 2+ signalling phenotype has minimal impact on myocardin expression in an automated differentiation assay using A7r5 cells. Cell Calcium 2021; 96:102369. [PMID: 33677175 DOI: 10.1016/j.ceca.2021.102369] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 02/06/2021] [Accepted: 02/08/2021] [Indexed: 01/12/2023]
Abstract
Vascular smooth muscle cells are unusual in that differentiated, contractile cells possess the capacity to "de-differentiate" into a synthetic phenotype that is characterized by being replicative, secretory, and migratory. One aspect of this phenotypic modulation is a shift from voltage-gated Ca2+ signalling in electrically coupled, differentiated cells to increased dependence on store-operated Ca2+ entry and sarcoplasmic reticulum Ca2+ release in synthetic cells. Conversely, an increased voltage-gated Ca2+ entry is seen when proliferating A7r5 smooth muscle cells quiesce. We asked whether this change in Ca2+ signalling was linked to changes in the expression of the phenotype-regulating transcriptional co-activator myocardin or α-smooth muscle actin, using correlative epifluorescence Ca2+ imaging and immunocytochemistry. Cells were cultured in growth media (DMEM, 10% serum, 25 mM glucose) or differentiation media (DMEM, 1% serum, 5 mM glucose). Coinciding with growth arrest, A7r5 cells became electrically coupled, and spontaneous Ca2+ signalling showed increasing dependence on L-type voltage-gated Ca2+ channels that were blocked with nifedipine (5 μM). These synchronized oscillations were modulated by ryanodine receptors, based on their sensitivity to dantrolene (5 μM). Actively growing cultures had spontaneous Ca2+ transients that were insensitive to nifedipine and dantrolene but were blocked by inhibition of the sarco-endoplasmic reticulum ATPase with cyclopiazonic acid (10 μM). In cells treated with differentiation media, myocardin and αSMA immunoreactivity increased prior to changes in the Ca2+ signalling phenotype, while chronic inhibition of voltage-gated Ca2+ entry modestly increased immunoreactivity of myocardin. Stepwise regression analyses suggested that changes in myocardin expression had a weak relationship with Ca2+ signalling synchronicity, but not frequency or amplitude. In conclusion, we report a 96-well assay and analytical pipeline to study the link between Ca2+ signalling and smooth muscle differentiation. This assay showed that changes in the expression of two molecular differentiation markers (myocardin and αSMA) tended to precede changes in the Ca2+ signalling phenotype.
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Bagge EK, Fujimori-Tonou N, Kubota-Sakashita M, Kasahara T, Kato T. Unbiased PCR-free spatio-temporal mapping of the mtDNA mutation spectrum reveals brain region-specific responses to replication instability. BMC Biol 2020; 18:150. [PMID: 33097039 PMCID: PMC7585204 DOI: 10.1186/s12915-020-00890-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 10/06/2020] [Indexed: 12/24/2022] Open
Abstract
Background The accumulation of mtDNA mutations in different tissues from various mouse models has been widely studied especially in the context of mtDNA mutation-driven ageing but has been confounded by the inherent limitations of the most widely used approaches. By implementing a method to sequence mtDNA without PCR amplification prior to library preparation, we map the full unbiased mtDNA mutation spectrum across six distinct brain regions from mice. Results We demonstrate that ageing-induced levels of mtDNA mutations (single nucleotide variants and deletions) reach stable levels at 50 weeks of age but can be further elevated specifically in the cortex, nucleus accumbens (NAc), and paraventricular thalamic nucleus (PVT) by expression of a proof-reading-deficient mitochondrial DNA polymerase, PolgD181A. The increase in single nucleotide variants increases the fraction of shared SNVs as well as their frequency, while characteristics of deletions remain largely unaffected. In addition, PolgD181A also induces an ageing-dependent accumulation of non-coding control-region multimers in NAc and PVT, a feature that appears almost non-existent in wild-type mice. Conclusions Our data provide a novel view of the spatio-temporal accumulation of mtDNA mutations using very limited tissue input. The differential response of brain regions to a state of replication instability provides insight into a possible heterogenic mitochondrial landscape across the brain that may be involved in the ageing phenotype and mitochondria-associated disorders.
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Affiliation(s)
- Emilie Kristine Bagge
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Center for Brain Science, Wako, Saitama, Japan
| | - Noriko Fujimori-Tonou
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Center for Brain Science, Wako, Saitama, Japan.,Current address: Support Unit for Bio-Material Analysis, Research Resources Division, RIKEN Center for Brain Science, Wako, Saitama, Japan
| | - Mie Kubota-Sakashita
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Center for Brain Science, Wako, Saitama, Japan
| | - Takaoki Kasahara
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Center for Brain Science, Wako, Saitama, Japan.,Current address: Career Development Program, RIKEN Center for Brain Science, Wako, Saitama, Japan
| | - Tadafumi Kato
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Center for Brain Science, Wako, Saitama, Japan. .,Department of Psychiatry and Behavioral Science, Juntendo University, Graduate School of Medicine, Hongo 2-1-1, Bunkyo, Tokyo 113-8421, Japan.
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Maeda R, Kami D, Maeda H, Shikuma A, Gojo S. High throughput single cell analysis of mitochondrial heteroplasmy in mitochondrial diseases. Sci Rep 2020; 10:10821. [PMID: 32616755 PMCID: PMC7331593 DOI: 10.1038/s41598-020-67686-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Accepted: 06/11/2020] [Indexed: 12/21/2022] Open
Abstract
Mitochondrial heteroplasmy, which fundamentally means intracellular heterogeneity of mitochondrial DNA (mtDNA), has been measured in a group of cells, regardless of intercellular heterogeneity. Ordinal methods for mitochondrial heteroplasmy cannot discriminate between an intercellular homogenic population composed of cells with similar intracellular heterogeneity for mtDNA and an intercellular heterogenic population composed of cells with different rates of mutated mtDNA. A high-throughput method to determine mitochondrial heteroplasmy in a single cell was developed by using droplet digital PCR with TaqMan polymerase in this study. This technique revealed that there are three different cell populations of cultured fibroblasts derived from patients with mitochondrial disease carrying a mutation in the mtDNA; cells with homoplasmy of either mutated or healthy mtDNA; and cells mixed with mutated and healthy mtDNA. The presence of intercellular heterogeneity, even in uniformed cultured fibroblasts, suggests that heterogeneity should exist among different kinds of cells. The diagnosis of intercellular heterogeneity with respect to mitochondrial heteroplasmy by this methodology could provide novel insight into developing a treatment strategy for mitochondrial diseases.
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Affiliation(s)
- Ryotaro Maeda
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465, Kajii cho, Kamigyo ku, Kyoto, 802-8566, Japan
| | - Daisuke Kami
- Department of Regenerative Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465, Kajii cho, Kamigyo ku, Kyoto, 802-8566, Japan
| | - Hideki Maeda
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465, Kajii cho, Kamigyo ku, Kyoto, 802-8566, Japan
| | - Akira Shikuma
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465, Kajii cho, Kamigyo ku, Kyoto, 802-8566, Japan
| | - Satoshi Gojo
- Department of Regenerative Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465, Kajii cho, Kamigyo ku, Kyoto, 802-8566, Japan.
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Castellani CA, Longchamps RJ, Sun J, Guallar E, Arking DE. Thinking outside the nucleus: Mitochondrial DNA copy number in health and disease. Mitochondrion 2020; 53:214-223. [PMID: 32544465 DOI: 10.1016/j.mito.2020.06.004] [Citation(s) in RCA: 164] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 05/19/2020] [Accepted: 06/08/2020] [Indexed: 02/07/2023]
Abstract
Mitochondrial DNA copy number (mtDNA-CN) is a biomarker of mitochondrial function and levels of mtDNA-CN have been reproducibly associated with overall mortality and a number of age-related diseases, including cardiovascular disease, chronic kidney disease, and cancer. Recent advancements in techniques for estimating mtDNA-CN, in particular the use of DNA microarrays and next-generation sequencing data, have led to the comprehensive assessment of mtDNA-CN across these and other diseases and traits. The importance of mtDNA-CN measures to disease and these advancing technologies suggest the potential for mtDNA-CN to be a useful biomarker in the clinic. While the exact mechanism(s) underlying the association of mtDNA-CN with disease remain to be elucidated, we review the existing literature which supports roles for inflammatory dynamics, immune function and alterations to cell signaling as consequences of variation in mtDNA-CN. We propose that future studies should focus on characterizing longitudinal, cell-type and cross-tissue profiles of mtDNA-CN as well as improving methods for measuring mtDNA-CN which will expand the potential for its use as a clinical biomarker.
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Affiliation(s)
- Christina A Castellani
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Ryan J Longchamps
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Jing Sun
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | - Eliseo Guallar
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States; The Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | - Dan E Arking
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States.
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An in Situ Atlas of Mitochondrial DNA in Mammalian Tissues Reveals High Content in Stem and Proliferative Compartments. THE AMERICAN JOURNAL OF PATHOLOGY 2020; 190:1565-1579. [PMID: 32304697 DOI: 10.1016/j.ajpath.2020.03.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 02/25/2020] [Accepted: 03/19/2020] [Indexed: 02/07/2023]
Abstract
Mitochondria regulate ATP production, metabolism, and cell death. Alterations in mitochondrial DNA (mtDNA) sequence and copy number are implicated in aging and organ dysfunction in diverse inherited and sporadic diseases. Because most measurements of mtDNA use homogenates of complex tissues, little is known about cell-type-specific mtDNA copy number heterogeneity in normal physiology, aging, and disease. Thus, the precise cell types whose loss of mitochondrial activity and altered mtDNA copy number that result in organ dysfunction in aging and disease have often not been clarified. Here, an in situ hybridization approach to generate a single-cell-resolution atlas of mtDNA content in mammalian tissues was validated. In hierarchically organized self-renewing tissues, higher levels of mtDNA were observed in stem/proliferative compartments compared with differentiated compartments. Striking zonal patterns of mtDNA levels in the liver reflected the known oxygen tension gradient. In the kidney, proximal and distal tubules had markedly higher mtDNA levels compared with cells within glomeruli and collecting duct epithelial cells. In mice, decreased mtDNA levels were visualized in renal tubules as a function of aging, which was prevented by calorie restriction. This study provides a novel approach for quantifying species- and cell-type-specific mtDNA copy number and dynamics in any normal or diseased tissue that can be used for monitoring the effects of interventions in animal and human studies.
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Longchamps RJ, Castellani CA, Yang SY, Newcomb CE, Sumpter JA, Lane J, Grove ML, Guallar E, Pankratz N, Taylor KD, Rotter JI, Boerwinkle E, Arking DE. Evaluation of mitochondrial DNA copy number estimation techniques. PLoS One 2020; 15:e0228166. [PMID: 32004343 PMCID: PMC6994099 DOI: 10.1371/journal.pone.0228166] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 01/08/2020] [Indexed: 12/16/2022] Open
Abstract
Mitochondrial DNA copy number (mtDNA-CN), a measure of the number of mitochondrial genomes per cell, is a minimally invasive proxy measure for mitochondrial function and has been associated with several aging-related diseases. Although quantitative real-time PCR (qPCR) is the current gold standard method for measuring mtDNA-CN, mtDNA-CN can also be measured from genotyping microarray probe intensities and DNA sequencing read counts. To conduct a comprehensive examination on the performance of these methods, we use known mtDNA-CN correlates (age, sex, white blood cell count, Duffy locus genotype, incident cardiovascular disease) to evaluate mtDNA-CN calculated from qPCR, two microarray platforms, as well as whole genome (WGS) and whole exome sequence (WES) data across 1,085 participants from the Atherosclerosis Risk in Communities (ARIC) study and 3,489 participants from the Multi-Ethnic Study of Atherosclerosis (MESA). We observe mtDNA-CN derived from WGS data is significantly more associated with known correlates compared to all other methods (p < 0.001). Additionally, mtDNA-CN measured from WGS is on average more significantly associated with traits by 5.6 orders of magnitude and has effect size estimates 5.8 times more extreme than the current gold standard of qPCR. We further investigated the role of DNA extraction method on mtDNA-CN estimate reproducibility and found mtDNA-CN estimated from cell lysate is significantly less variable than traditional phenol-chloroform-isoamyl alcohol (p = 5.44x10-4) and silica-based column selection (p = 2.82x10-7). In conclusion, we recommend the field moves towards more accurate methods for mtDNA-CN, as well as re-analyze trait associations as more WGS data becomes available from larger initiatives such as TOPMed.
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Affiliation(s)
- Ryan J. Longchamps
- Department of Genetic Medicine, McKusick-Nathans Institute, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Christina A. Castellani
- Department of Genetic Medicine, McKusick-Nathans Institute, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Stephanie Y. Yang
- Department of Genetic Medicine, McKusick-Nathans Institute, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Charles E. Newcomb
- Department of Genetic Medicine, McKusick-Nathans Institute, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Jason A. Sumpter
- Department of Genetic Medicine, McKusick-Nathans Institute, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - John Lane
- Department of Laboratory Medicine and Pathology, University of Minnesota Medical School, Minneapolis, MN, United States of America
| | - Megan L. Grove
- Human Genetics Center, Department of Epidemiology, Human Genetics, and Environmental Sciences, School of Public Health, The University of Texas Health Science Center at Houston, Houston, TX, United States of America
| | - Eliseo Guallar
- Department of Epidemiology and the Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States of America
| | - Nathan Pankratz
- Department of Laboratory Medicine and Pathology, University of Minnesota Medical School, Minneapolis, MN, United States of America
| | - Kent D. Taylor
- LABioMed and Department of Pediatrics, at Harbor-UCLA Medical Center, Institute for Translational Genomics and Population Sciences, Torrance, CA, United States of America
| | - Jerome I. Rotter
- LABioMed and Department of Pediatrics, at Harbor-UCLA Medical Center, Institute for Translational Genomics and Population Sciences, Torrance, CA, United States of America
| | - Eric Boerwinkle
- Human Genetics Center, Department of Epidemiology, Human Genetics, and Environmental Sciences, School of Public Health, The University of Texas Health Science Center at Houston, Houston, TX, United States of America
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, United States of America
| | - Dan E. Arking
- Department of Genetic Medicine, McKusick-Nathans Institute, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
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Patel SH, Yue F, Saw SK, Foguth R, Cannon JR, Shannahan JH, Kuang S, Sabbaghi A, Carroll CC. Advanced Glycation End-Products Suppress Mitochondrial Function and Proliferative Capacity of Achilles Tendon-Derived Fibroblasts. Sci Rep 2019; 9:12614. [PMID: 31471548 PMCID: PMC6717202 DOI: 10.1038/s41598-019-49062-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 08/16/2019] [Indexed: 02/07/2023] Open
Abstract
Debilitating cases of tendon pain and degeneration affect the majority of diabetic individuals. The high rate of tendon degeneration persists even when glucose levels are well controlled, suggesting that other mechanisms may drive tendon degeneration in diabetic patients. The purpose of this study was to investigate the impact of advanced glycation end-products on tendon fibroblasts to further our mechanistic understanding of the development and progression of diabetic tendinopathy. We proposed that advanced glycation end-products would induce limitations to mitochondrial function and proliferative capacity in tendon-derived fibroblasts, restricting their ability to maintain biosynthesis of tendon extracellular matrix. Using an in-vitro cell culture system, rat Achilles tendon fibroblasts were treated with glycolaldehyde-derived advanced glycation end-products (0, 50, 100, and 200 μg/ml) for 48 hours in normal glucose (5.5 mM) and high glucose (25 mM) conditions. We demonstrate that tendon fibroblasts treated with advanced glycation end-products display reduced ATP production, electron transport efficiency, and proliferative capacity. These impairments were coupled with alterations in mitochondrial DNA content and expression of genes associated with extracellular matrix remodeling, mitochondrial energy metabolism, and apoptosis. Our findings suggest that advanced glycation end-products disrupt tendon fibroblast homeostasis and may be involved in the development and progression of diabetic tendinopathy.
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Affiliation(s)
- Shivam H Patel
- Department of Health and Kinesiology, Purdue University, West Lafayette, IN, USA
| | - Feng Yue
- Department of Animal Sciences, Purdue University, West Lafayette, IN, USA
| | - Shannon K Saw
- Department of Health and Kinesiology, Purdue University, West Lafayette, IN, USA
| | - Rachel Foguth
- School of Health Sciences, Purdue University, West Lafayette, IN, USA
- Purdue Institute for Integrative Neuroscience, West Lafayette, IN, USA
| | - Jason R Cannon
- School of Health Sciences, Purdue University, West Lafayette, IN, USA
- Purdue Institute for Integrative Neuroscience, West Lafayette, IN, USA
| | | | - Shihuan Kuang
- Department of Animal Sciences, Purdue University, West Lafayette, IN, USA
| | - Arman Sabbaghi
- Department of Statistics, Purdue University, West Lafayette, IN, USA
| | - Chad C Carroll
- Department of Health and Kinesiology, Purdue University, West Lafayette, IN, USA.
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, USA.
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