1
|
Zheng M, Jiang Q, You J, Gao B, Cui W, Yao W, Su F, Sun X, La L. Myricanol represses renal fibrosis by activating TFAM and ZNRF1 to inhibit tubular epithelial cells ferroptosis. Eur J Pharmacol 2024:176999. [PMID: 39349116 DOI: 10.1016/j.ejphar.2024.176999] [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: 02/25/2024] [Revised: 05/19/2024] [Accepted: 09/12/2024] [Indexed: 10/02/2024]
Abstract
BACKGROUND Mitochondrial dysfunction induces ferroptosis in renal tubular epithelial cells (TECs). Studies have shown that myricanol maintains muscle cell function by enhancing mitochondrial energy metabolism. HYPOTHESIS Myricanol delays renal fibrosis by maintaining mitochondrial integrity and inhibiting ferroptosis in TECs. METHODS Mice kidney lacking mitochondrial transcription factor A (TFAM), blood specimens, or pathological sections of renal tissue from patients with renal failure were used to explore the relationship between mitochondrial and renal functions. Erastin induced-TECs ferroptosis was used to study the potential mechanism by which TFAM regulates renal fibrosis. Chronic kidney disease (CKD) mice were utilized to explore the anti-fibrotic effects of myricanol. RESULTS The number of mitochondria and TFAM expression were decreased in human blood samples and pathological sections. Renal TFAM-deficient mice exhibited abnormalities in renal function, including ferroptosis and fibrosis. Ferrostatin-1 significantly inhibited renal fibrosis by preventing TECs ferroptosis. Transcriptional sequencing results indicated that zinc and ring finger 1 (ZNRF1) were important downstream genes of TFAM that regulate ferroptosis. We demonstrated that TFAM deficiency and ferroptosis, which destroyed interaction between ZNRF1 and the iron transport-related protein lipocalin-2 (LCN2), but myricanol clould reverse this effect. Overexpression of ZNRF1 efficiently maintained mitochondrial integrity and inhibited renal fibrosis. Myricanol ameliorated transforming growth factor β1-induced mitochondrial impairment. We firstly confirmed that myricanol efficiently improved renal function and suppresses fibrosis in CKD mice. CONCLUSIONS Myricanol efficiently inhibit fibrosis through activating TFAM to stimulate the interaction between ZNRF1 and LCN2.
Collapse
Affiliation(s)
- Min Zheng
- Department of Pharmacy, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Qiao Jiang
- Department of Pharmacy, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Junxiong You
- The Key Laboratory of Molecular Biology, State Administration of Traditional Chinese Medicine, School of Traditional Chinese Medicine, Southern Medical University, Guangzhou 510515, China
| | - Baogui Gao
- The Key Laboratory of Molecular Biology, State Administration of Traditional Chinese Medicine, School of Traditional Chinese Medicine, Southern Medical University, Guangzhou 510515, China
| | - Weiwei Cui
- Department of Imaging, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Wanyu Yao
- The Key Laboratory of Molecular Biology, State Administration of Traditional Chinese Medicine, School of Traditional Chinese Medicine, Southern Medical University, Guangzhou 510515, China
| | - Fengqing Su
- Department of Pharmacy, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Xuegang Sun
- The Key Laboratory of Molecular Biology, State Administration of Traditional Chinese Medicine, School of Traditional Chinese Medicine, Southern Medical University, Guangzhou 510515, China.
| | - Lei La
- Department of Pharmacy, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.
| |
Collapse
|
2
|
Bayazit MB, Francois A, McGrail E, Accornero F, Stratton MS. mt-tRNAs in the polymerase gamma mutant heart. THE JOURNAL OF CARDIOVASCULAR AGING 2023; 3:41. [PMID: 38235059 PMCID: PMC10793997 DOI: 10.20517/jca.2023.26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Introduction Mice harboring a D257A mutation in the proofreading domain of the mitochondrial DNA polymerase, Polymerase Gamma (POLG), experience severe metabolic dysfunction and display hallmarks of accelerated aging. We previously reported a mitochondrial unfolded protein response (UPTmt) - like (UPRmt-like) gene and protein expression pattern in the right ventricular tissue of POLG mutant mice. Aim We sought to determine if POLG mutation altered the expression of genes encoded by the mitochondria in a way that might also reduce proteotoxic stress. Methods and Results The expression of genes encoded by the mitochondrial DNA was interrogated via RNA-seq and northern blot analysis. A striking, location-dependent effect was seen in the expression of mitochondrial-encoded tRNAs in the POLG mutant as assayed by RNA-seq. These expression changes were negatively correlated with the tRNA partner amino acid's amyloidogenic potential. Direct measurement by northern blot was conducted on candidate mt-tRNAs identified from the RNA-seq. This analysis confirmed reduced expression of MT-TY in the POLG mutant but failed to show increased expression of MT-TP, which was dramatically increased in the RNA-seq data. Conclusion We conclude that reduced expression of amyloid-associated mt-tRNAs is another indication of adaptive response to severe mitochondrial dysfunction in the POLG mutant. Incongruence between RNA-seq and northern blot measurement of MT-TP expression points towards the existence of mt-tRNA post-transcriptional modification regulation in the POLG mutant that alters either polyA capture or cDNA synthesis in RNA-seq library generation. Together, these data suggest that 1) evolution has distributed mt-tRNAs across the circular mitochondrial genome to allow chromosomal location-dependent mt-tRNA regulation (either by expression or PTM) and 2) this regulation is cognizant of the tRNA partner amino acid's amyloidogenic properties.
Collapse
Affiliation(s)
- M. Bilal Bayazit
- Department of Physiology & Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Ashley Francois
- Department of Physiology & Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Erin McGrail
- Department of Physiology & Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Federica Accornero
- Department of Physiology & Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Matthew S. Stratton
- Department of Physiology & Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| |
Collapse
|
3
|
Meyrick J, Stefanetti RJ, Errington L, McFarland R, Gorman GS, Lax NZ. Model systems informing mechanisms and drug discovery: a systematic review of POLG-related disease models. Wellcome Open Res 2023. [DOI: 10.12688/wellcomeopenres.18637.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Introduction Pathogenic variants in the gene encoding the catalytic subunit of DNA polymerase gamma (POLG), comprise an important single-gene cause of inherited mitochondrial disorders. Clinical manifestations are now recognised as an array of overlapping clinical features rather than discrete syndromes as originally conceptualised. Animal and cellular models have been used to address numerous scientific questions, from basic science to the development and assessment of novel therapies. Here, we sought to perform a systematic review of the existing models used in mitochondrial research and their effectiveness in recapitulating POLG-related disease. Methods Four databases were searched from inception to May 31, 2022: MEDLINE, Scopus, Web of Science, and Cochrane Review. Original articles available in English, reporting the use of a model system designed to recapitulate POLG-related disease, or related pathogenicity, were eligible for inclusion. Risk of bias and the methodological quality of articles were assessed by an adapted version of the Cochrane Risk of Bias Tool, with the quality of evidence synthesized across each model. Results A total of 55 articles, including seven model organisms (Human, yeast [Saccharomyces cerevisiae and Schizosaccharomyces pombe], Drosophila, Mouse, Nematoda, and Zebrafish) with 258 distinct variants were included. Of these, 66% (N=38) of articles recapitulated mitochondrial DNA (mtDNA) depletion and 42% (N=23) recapitulated POLG-related disease. Thirty-three percent of articles (N=18/55) utilised tissue-specific models of POLG-related dysfunction, while 13% (N=7) investigated the effect of potential therapeutics in POLG-related mitochondrial disorders. Discussion The available evidence supporting the ability of models for POLG-related disease to recapitulate molecular mechanisms and phenotype is limited, inconsistent and of poor methodologic quality. Further success in examining and translating novel therapies into effective treatments will be enhanced by the availability of more robust models that better recapitulate the entire spectrum of POLG-related disease. PROSPERO registration: CRD42021234883
Collapse
|
4
|
Rahman MM, Young CKJ, Goffart S, Pohjoismäki JLO, Young MJ. Heterozygous p.Y955C mutation in DNA polymerase γ leads to alterations in bioenergetics, complex I subunit expression, and mtDNA replication. J Biol Chem 2022; 298:102196. [PMID: 35760101 PMCID: PMC9307957 DOI: 10.1016/j.jbc.2022.102196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 06/16/2022] [Accepted: 06/17/2022] [Indexed: 12/03/2022] Open
Abstract
In human cells, ATP is generated using oxidative phosphorylation machinery, which is inoperable without proteins encoded by mitochondrial DNA (mtDNA). The DNA polymerase gamma (Polγ) repairs and replicates the multicopy mtDNA genome in concert with additional factors. The Polγ catalytic subunit is encoded by the POLG gene, and mutations in this gene cause mtDNA genome instability and disease. Barriers to studying the molecular effects of disease mutations include scarcity of patient samples and a lack of available mutant models; therefore, we developed a human SJCRH30 myoblast cell line model with the most common autosomal dominant POLG mutation, c.2864A>G/p.Y955C, as individuals with this mutation can present with progressive skeletal muscle weakness. Using on-target sequencing, we detected a 50% conversion frequency of the mutation, confirming heterozygous Y955C substitution. We found mutated cells grew slowly in a glucose-containing medium and had reduced mitochondrial bioenergetics compared with the parental cell line. Furthermore, growing Y955C cells in a galactose-containing medium to obligate mitochondrial function enhanced these bioenergetic deficits. Also, we show complex I NDUFB8 and ND3 protein levels were decreased in the mutant cell line, and the maintenance of mtDNA was severely impaired (i.e., lower copy number, fewer nucleoids, and an accumulation of Y955C-specific replication intermediates). Finally, we show the mutant cells have increased sensitivity to the mitochondrial toxicant 2′-3′-dideoxycytidine. We expect this POLG Y955C cell line to be a robust system to identify new mitochondrial toxicants and therapeutics to treat mitochondrial dysfunction.
Collapse
Affiliation(s)
- Md Mostafijur Rahman
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901
| | - Carolyn K J Young
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901
| | - Steffi Goffart
- Department of Environmental and Biological Sciences, University of Eastern Finland, 80101 Joensuu, Finland
| | - Jaakko L O Pohjoismäki
- Department of Environmental and Biological Sciences, University of Eastern Finland, 80101 Joensuu, Finland
| | - Matthew J Young
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901.
| |
Collapse
|
5
|
Gorr MW, Francois A, Marcho LM, Saldana T, McGrail E, Sun N, Stratton MS. Molecular signature of cardiac remodeling associated with Polymerase Gamma mutation. Life Sci 2022; 298:120469. [PMID: 35283176 PMCID: PMC9158136 DOI: 10.1016/j.lfs.2022.120469] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/02/2022] [Accepted: 03/06/2022] [Indexed: 11/28/2022]
Abstract
AIMS Metabolic function/dysfunction is central to aging biology. This is well illustrated by the Polymerase Gamma (POLG) mutant mouse where a key residue of the mitochondrial DNA polymerase is mutated (D257A), causing loss of mitochondrial DNA stability and dramatically accelerated aging processes. Given known cardiac phenotypes in the POLG mutant, we sought to characterize the course of cardiac dysfunction in the POLG mutant to guide future intervention studies. MATERIALS AND METHODS Cardiac echocardiography and terminal hemodynamic analyses were used to define the course of dysfunction in the right and left cardiac ventricles in the POLG mutant. We also conducted RNA-seq analysis on cardiac right ventricles to identify mechanisms engaged by severe metabolic dysfunction and compared this analysis to several publically available datasets. KEY FINDINGS Interesting sex differences were noted as female POLG mutants died earlier than male POLG mutants and LV chamber diameters were impacted earlier in females than males. Moreover, male mutants showed LV wall thinning while female mutant LV walls were thicker. Both males and females displayed significant RV hypertrophy. POLG mutants displayed a gene expression pattern associated with inflammation, fibrosis, and heart failure. Finally, comparative omics analyses of publically available data provide additional mechanistic and therapeutic insights. SIGNIFICANCE Aging-associated cardiac dysfunction is a growing clinical problem. This work uncovers sex-specific cardiac responses to severe metabolic dysfunction that are reminiscent of patterns seen in human heart failure and provides insights to the molecular mechanisms engaged downstream of severe metabolic dysfunction that warrant further investigation.
Collapse
Affiliation(s)
- Matthew W. Gorr
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA,College of Nursing, The Ohio State University, Columbus, OH, USA
| | - Ashley Francois
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Lynn M. Marcho
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Ty Saldana
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Erin McGrail
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Nuo Sun
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Matthew S. Stratton
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| |
Collapse
|
6
|
Wang H, Han Y, Li S, Chen Y, Chen Y, Wang J, Zhang Y, Zhang Y, Wang J, Xia Y, Yuan J. Mitochondrial DNA Depletion Syndrome and Its Associated Cardiac Disease. Front Cardiovasc Med 2022; 8:808115. [PMID: 35237671 PMCID: PMC8882844 DOI: 10.3389/fcvm.2021.808115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 12/23/2021] [Indexed: 12/06/2022] Open
Abstract
Mitochondria is a ubiquitous, energy-supplying (ATP-based) organelle found in nearly all eukaryotes. It acts as a “power plant” by producing ATP through oxidative phosphorylation, providing energy for the cell. The bioenergetic functions of mitochondria are regulated by nuclear genes (nDNA). Mitochondrial DNA (mtDNA) and respiratory enzymes lose normal structure and function when nuclear genes encoding the related mitochondrial factors are impaired, resulting in deficiency in energy production. Massive generation of reactive oxygen species and calcium overload are common causes of mitochondrial diseases. The mitochondrial depletion syndrome (MDS) is associated with the mutations of mitochondrial genes in the nucleus. It is a heterogeneous group of progressive disorders characterized by the low mtDNA copy number. TK2, FBXL4, TYPM, and AGK are genes known to be related to MDS. More recent studies identified new mutation loci associated with this disease. Herein, we first summarize the structure and function of mitochondria, and then discuss the characteristics of various types of MDS and its association with cardiac diseases.
Collapse
Affiliation(s)
- Haiying Wang
- Department of Physiology, Institute of Basic Medical College, Jining Medical University, Jining, China
| | - Yijun Han
- Clinical Medical College, Jining Medical University, Jining, China
| | - Shenwei Li
- Institute of Basic Medical College, Jining Medical University, Jining, China
| | - Yunan Chen
- Institute of Basic Medical College, Jining Medical University, Jining, China
| | - Yafen Chen
- Institute of Basic Medical College, Jining Medical University, Jining, China
| | - Jing Wang
- Dongying Fifth People's Hospital, Dongying, China
| | - Yuqing Zhang
- Institute of Basic Medical College, Jining Medical University, Jining, China
| | - Yawen Zhang
- Institute of Basic Medical College, Jining Medical University, Jining, China
| | - Jingsuo Wang
- Institute of Basic Medical College, Jining Medical University, Jining, China
| | - Yong Xia
- Key Laboratory of Precision Oncology of Shandong Higher Education, Institute of Precision Medicine, Jining Medical University, Jining, China
- Yong Xia
| | - Jinxiang Yuan
- The Collaborative Innovation Center, Jining Medical University, Jining, China
- *Correspondence: Jinxiang Yuan
| |
Collapse
|
7
|
Morin AL, Win PW, Lin AZ, Castellani CA. Mitochondrial genomic integrity and the nuclear epigenome in health and disease. Front Endocrinol (Lausanne) 2022; 13:1059085. [PMID: 36419771 PMCID: PMC9678080 DOI: 10.3389/fendo.2022.1059085] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 10/19/2022] [Indexed: 11/09/2022] Open
Abstract
Bidirectional crosstalk between the nuclear and mitochondrial genomes is essential for proper cell functioning. Mitochondrial DNA copy number (mtDNA-CN) and heteroplasmy influence mitochondrial function, which can influence the nuclear genome and contribute to health and disease. Evidence shows that mtDNA-CN and heteroplasmic variation are associated with aging, complex disease, and all-cause mortality. Further, the nuclear epigenome may mediate the effects of mtDNA variation on disease. In this way, mitochondria act as an environmental biosensor translating vital information about the state of the cell to the nuclear genome. Cellular communication between mtDNA variation and the nuclear epigenome can be achieved by modification of metabolites and intermediates of the citric acid cycle and oxidative phosphorylation. These essential molecules (e.g. ATP, acetyl-CoA, ɑ-ketoglutarate and S-adenosylmethionine) act as substrates and cofactors for enzymes involved in epigenetic modifications. The role of mitochondria as an environmental biosensor is emerging as a critical modifier of disease states. Uncovering the mechanisms of these dynamics in disease processes is expected to lead to earlier and improved treatment for a variety of diseases. However, the influence of mtDNA-CN and heteroplasmy variation on mitochondrially-derived epigenome-modifying metabolites and intermediates is poorly understood. This perspective will focus on the relationship between mtDNA-CN, heteroplasmy, and epigenome modifying cofactors and substrates, and the influence of their dynamics on the nuclear epigenome in health and disease.
Collapse
Affiliation(s)
- Amanda L. Morin
- Department of Pathology and Laboratory Medicine, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Phyo W. Win
- Department of Pathology and Laboratory Medicine, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Angela Z. Lin
- Department of Pathology and Laboratory Medicine, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Christina A. Castellani
- Department of Pathology and Laboratory Medicine, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Department of Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- *Correspondence: Christina A. Castellani,
| |
Collapse
|
8
|
Nunes JPS, Andrieux P, Brochet P, Almeida RR, Kitano E, Honda AK, Iwai LK, Andrade-Silva D, Goudenège D, Alcântara Silva KD, Vieira RDS, Levy D, Bydlowski SP, Gallardo F, Torres M, Bocchi EA, Mano M, Santos RHB, Bacal F, Pomerantzeff P, Laurindo FRM, Teixeira PC, Nakaya HI, Kalil J, Procaccio V, Chevillard C, Cunha-Neto E. Co-Exposure of Cardiomyocytes to IFN-γ and TNF-α Induces Mitochondrial Dysfunction and Nitro-Oxidative Stress: Implications for the Pathogenesis of Chronic Chagas Disease Cardiomyopathy. Front Immunol 2021; 12:755862. [PMID: 34867992 PMCID: PMC8632642 DOI: 10.3389/fimmu.2021.755862] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 10/11/2021] [Indexed: 12/15/2022] Open
Abstract
Infection by the protozoan Trypanosoma cruzi causes Chagas disease cardiomyopathy (CCC) and can lead to arrhythmia, heart failure and death. Chagas disease affects 8 million people worldwide, and chronic production of the cytokines IFN-γ and TNF-α by T cells together with mitochondrial dysfunction are important players for the poor prognosis of the disease. Mitochondria occupy 40% of the cardiomyocytes volume and produce 95% of cellular ATP that sustain the life-long cycles of heart contraction. As IFN-γ and TNF-α have been described to affect mitochondrial function, we hypothesized that IFN-γ and TNF-α are involved in the myocardial mitochondrial dysfunction observed in CCC patients. In this study, we quantified markers of mitochondrial dysfunction and nitro-oxidative stress in CCC heart tissue and in IFN-γ/TNF-α-stimulated AC-16 human cardiomyocytes. We found that CCC myocardium displayed increased levels of nitro-oxidative stress and reduced mitochondrial DNA as compared with myocardial tissue from patients with dilated cardiomyopathy (DCM). IFN-γ/TNF-α treatment of AC-16 cardiomyocytes induced increased nitro-oxidative stress and decreased the mitochondrial membrane potential (ΔΨm). We found that the STAT1/NF-κB/NOS2 axis is involved in the IFN-γ/TNF-α-induced decrease of ΔΨm in AC-16 cardiomyocytes. Furthermore, treatment with mitochondria-sparing agonists of AMPK, NRF2 and SIRT1 rescues ΔΨm in IFN-γ/TNF-α-stimulated cells. Proteomic and gene expression analyses revealed that IFN-γ/TNF-α-treated cells corroborate mitochondrial dysfunction, transmembrane potential of mitochondria, altered fatty acid metabolism and cardiac necrosis/cell death. Functional assays conducted on Seahorse respirometer showed that cytokine-stimulated cells display decreased glycolytic and mitochondrial ATP production, dependency of fatty acid oxidation as well as increased proton leak and non-mitochondrial oxygen consumption. Together, our results suggest that IFN-γ and TNF-α cause direct damage to cardiomyocytes’ mitochondria by promoting oxidative and nitrosative stress and impairing energy production pathways. We hypothesize that treatment with agonists of AMPK, NRF2 and SIRT1 might be an approach to ameliorate the progression of Chagas disease cardiomyopathy.
Collapse
Affiliation(s)
- João Paulo Silva Nunes
- Laboratory of Immunology, Heart Institute (Incor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.,Division of Clinical Immunology and Allergy, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.,iii-Institute for Investigation in Immunology, Instituto Nacional de Ciência e Tecnologia (INCT), São Paulo, Brazil.,INSERM, UMR_1090, Aix Marseille Université, TAGC Theories and Approaches of Genomic Complexity, Institut MarMaRa, Marseille, France
| | - Pauline Andrieux
- INSERM, UMR_1090, Aix Marseille Université, TAGC Theories and Approaches of Genomic Complexity, Institut MarMaRa, Marseille, France
| | - Pauline Brochet
- INSERM, UMR_1090, Aix Marseille Université, TAGC Theories and Approaches of Genomic Complexity, Institut MarMaRa, Marseille, France
| | - Rafael Ribeiro Almeida
- Laboratory of Immunology, Heart Institute (Incor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.,iii-Institute for Investigation in Immunology, Instituto Nacional de Ciência e Tecnologia (INCT), São Paulo, Brazil
| | - Eduardo Kitano
- Laboratory of Immunology, Heart Institute (Incor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - André Kenji Honda
- Laboratory of Immunology, Heart Institute (Incor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Leo Kei Iwai
- Laboratório Especial de Toxinologia Aplicada, Center of Toxins, Immune-Response and Cell Signaling (CeTICS), Instituto Butantan, São Paulo, Brazil
| | - Débora Andrade-Silva
- Laboratório Especial de Toxinologia Aplicada, Center of Toxins, Immune-Response and Cell Signaling (CeTICS), Instituto Butantan, São Paulo, Brazil
| | - David Goudenège
- Department of Biochemistry and Genetics, University Hospital of Angers, Angers, France
| | - Karla Deysiree Alcântara Silva
- Laboratory of Immunology, Heart Institute (Incor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.,Division of Clinical Immunology and Allergy, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Raquel de Souza Vieira
- Laboratory of Immunology, Heart Institute (Incor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Débora Levy
- Laboratory of Immunology, Heart Institute (Incor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Sergio Paulo Bydlowski
- Laboratory of Immunology, Heart Institute (Incor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Frédéric Gallardo
- INSERM, UMR_1090, Aix Marseille Université, TAGC Theories and Approaches of Genomic Complexity, Institut MarMaRa, Marseille, France
| | - Magali Torres
- INSERM, UMR_1090, Aix Marseille Université, TAGC Theories and Approaches of Genomic Complexity, Institut MarMaRa, Marseille, France
| | - Edimar Alcides Bocchi
- Heart Failure Team, Heart Institute (Incor) Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Miguel Mano
- Functional Genomics and RNA-based Therapeutics Laboratory, Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal
| | | | - Fernando Bacal
- Division of Surgery, Heart Institute, School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Pablo Pomerantzeff
- Division of Surgery, Heart Institute, School of Medicine, University of São Paulo, São Paulo, Brazil
| | | | - Priscila Camillo Teixeira
- Translational Research Sciences, Pharma Research and Early Development F. Hoffmann-La Roche, Basel, Switzerland
| | | | - Jorge Kalil
- Laboratory of Immunology, Heart Institute (Incor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.,Division of Clinical Immunology and Allergy, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.,iii-Institute for Investigation in Immunology, Instituto Nacional de Ciência e Tecnologia (INCT), São Paulo, Brazil
| | - Vincent Procaccio
- MitoLab, UMR CNRS 6015-INSERM U1083, Université d'Angers, Angers, France
| | - Christophe Chevillard
- INSERM, UMR_1090, Aix Marseille Université, TAGC Theories and Approaches of Genomic Complexity, Institut MarMaRa, Marseille, France
| | - Edecio Cunha-Neto
- Laboratory of Immunology, Heart Institute (Incor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.,Division of Clinical Immunology and Allergy, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.,iii-Institute for Investigation in Immunology, Instituto Nacional de Ciência e Tecnologia (INCT), São Paulo, Brazil
| |
Collapse
|
9
|
Santos JH. Mitochondria signaling to the epigenome: A novel role for an old organelle. Free Radic Biol Med 2021; 170:59-69. [PMID: 33271282 PMCID: PMC8166959 DOI: 10.1016/j.freeradbiomed.2020.11.016] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 11/16/2020] [Accepted: 11/17/2020] [Indexed: 12/23/2022]
Abstract
Epigenetic modifications influence gene expression programs ultimately dictating physiological outcomes. In the past decades, an increasing body of work has demonstrated that the enzymes that deposit and/or remove epigenetic marks on DNA or histones use metabolites as substrates or co-factors, rendering the epigenome sensitive to metabolic changes. In this context, acetyl-CoA and α-ketoglutarate have been recognized as critical for epigenetics, impinging on histone marks and nuclear DNA methylation patterns. Given that these metabolites are primarily generated in the mitochondria through the tricarboxylic acid cycle (TCA), the requirement of proper mitochondrial function for maintenance of the epigenetic landscape seems obvious. Nevertheless, it was not until recently when the epigenomic outcomes of mitochondrial dysfunction were tested, revealing mitochondria's far-reaching impact on epigenetics. This review will focus on data that directly tested the role of mitochondria on the epigenetic landscape, the mechanisms by which mitochondrial dysfunction may dysregulate the epigenome and gene expression, and their potential implications to health and disease.
Collapse
Affiliation(s)
- Janine Hertzog Santos
- National Toxicology Program Laboratory (NTPL), National Toxicology Program (NTP), National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park (RTP), NC, USA.
| |
Collapse
|
10
|
Li C, Zhang Y, Liu J, Kang R, Klionsky DJ, Tang D. Mitochondrial DNA stress triggers autophagy-dependent ferroptotic death. Autophagy 2021; 17:948-960. [PMID: 32186434 PMCID: PMC8078708 DOI: 10.1080/15548627.2020.1739447] [Citation(s) in RCA: 214] [Impact Index Per Article: 71.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 02/06/2020] [Accepted: 02/28/2020] [Indexed: 12/24/2022] Open
Abstract
Pancreatic cancer tends to be highly resistant to current therapy and remains one of the great challenges in biomedicine with very low 5-year survival rates. Here, we report that zalcitabine, an antiviral drug for human immunodeficiency virus infection, can suppress the growth of primary and immortalized human pancreatic cancer cells through the induction of ferroptosis, an iron-dependent form of regulated cell death. Mechanically, this effect relies on zalcitabine-induced mitochondrial DNA stress, which activates the STING1/TMEM173-mediated DNA sensing pathway, leading to macroautophagy/autophagy-dependent ferroptotic cell death via lipid peroxidation, but not a type I interferon response. Consequently, the genetic and pharmacological inactivation of the autophagy-dependent ferroptosis pathway diminishes the anticancer effects of zalcitabine in cell culture and animal models. Together, these findings not only provide a new approach for pancreatic cancer therapy but also increase our understanding of the interplay between autophagy and DNA damage response in shaping cell death.Abbreviations: ALOX: arachidonate lipoxygenase; ARNTL/BMAL1: aryl hydrocarbon receptor nuclear translocator-like; ATM: ATM serine/threonine kinase; ATG: autophagy-related; cGAMP: cyclic GMP-AMP; CGAS: cyclic GMP-AMP synthase; ER: endoplasmic reticulum; FANCD2: FA complementation group D2; GPX4: glutathione peroxidase 4; IFNA1/IFNα: interferon alpha 1; IFNB1/IFNβ: interferon beta 1; MAP1LC3B/LC3: microtubule-associated protein 1 light chain 3 beta; MDA: malondialdehyde; mtDNA: mitochondrial DNA; NCOA4: nuclear receptor coactivator 4; PDAC: pancreatic ductal adenocarcinoma; POLG: DNA polymerase gamma, catalytic subunit; qRT-PCR: quantitative polymerase chain reaction; RCD: regulated cell death; ROS: reactive oxygen species; SLC7A11: solute carrier family 7 member 11; STING1/TMEM173: stimulator of interferon response cGAMP interactor 1; TFAM: transcription factor A, mitochondrial.
Collapse
Affiliation(s)
- Changfeng Li
- Department of Endoscopy Center, China-Japan Union Hospital of Jilin University, Changchun, Jilin, China
| | - Ying Zhang
- Department of Endoscopy Center, China-Japan Union Hospital of Jilin University, Changchun, Jilin, China
| | - Jiao Liu
- The Third Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Rui Kang
- Department of Surgery, UT Southwestern Medical Center, Dallas, TX, USA
| | - Daniel J. Klionsky
- Life Sciences Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Daolin Tang
- The Third Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, China
- Department of Surgery, UT Southwestern Medical Center, Dallas, TX, USA
| |
Collapse
|
11
|
Khan YA, Jungreis I, Wright JC, Mudge JM, Choudhary JS, Firth AE, Kellis M. Evidence for a novel overlapping coding sequence in POLG initiated at a CUG start codon. BMC Genet 2020; 21:25. [PMID: 32138667 PMCID: PMC7059407 DOI: 10.1186/s12863-020-0828-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 02/19/2020] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND POLG, located on nuclear chromosome 15, encodes the DNA polymerase γ(Pol γ). Pol γ is responsible for the replication and repair of mitochondrial DNA (mtDNA). Pol γ is the only DNA polymerase found in mitochondria for most animal cells. Mutations in POLG are the most common single-gene cause of diseases of mitochondria and have been mapped over the coding region of the POLG ORF. RESULTS Using PhyloCSF to survey alternative reading frames, we found a conserved coding signature in an alternative frame in exons 2 and 3 of POLG, herein referred to as ORF-Y that arose de novo in placental mammals. Using the synplot2 program, synonymous site conservation was found among mammals in the region of the POLG ORF that is overlapped by ORF-Y. Ribosome profiling data revealed that ORF-Y is translated and that initiation likely occurs at a CUG codon. Inspection of an alignment of mammalian sequences containing ORF-Y revealed that the CUG codon has a strong initiation context and that a well-conserved predicted RNA stem-loop begins 14 nucleotides downstream. Such features are associated with enhanced initiation at near-cognate non-AUG codons. Reanalysis of the Kim et al. (2014) draft human proteome dataset yielded two unique peptides that map unambiguously to ORF-Y. An additional conserved uORF, herein referred to as ORF-Z, was also found in exon 2 of POLG. Lastly, we surveyed Clinvar variants that are synonymous with respect to the POLG ORF and found that most of these variants cause amino acid changes in ORF-Y or ORF-Z. CONCLUSIONS We provide evidence for a novel coding sequence, ORF-Y, that overlaps the POLG ORF. Ribosome profiling and mass spectrometry data show that ORF-Y is expressed. PhyloCSF and synplot2 analysis show that ORF-Y is subject to strong purifying selection. An abundance of disease-correlated mutations that map to exons 2 and 3 of POLG but also affect ORF-Y provides potential clinical significance to this finding.
Collapse
Affiliation(s)
- Yousuf A Khan
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, 94305, USA.
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK.
| | - Irwin Jungreis
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.
| | - James C Wright
- Functional Proteomics, Division of Cancer Biology, Institute of Cancer Research, 123 Old Brompton Road, London, SW7 3RP, UK
| | - Jonathan M Mudge
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
| | | | - Andrew E Firth
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Manolis Kellis
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| |
Collapse
|
12
|
Mitochondrial Genome (mtDNA) Mutations that Generate Reactive Oxygen Species. Antioxidants (Basel) 2019; 8:antiox8090392. [PMID: 31514455 PMCID: PMC6769445 DOI: 10.3390/antiox8090392] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 09/09/2019] [Accepted: 09/09/2019] [Indexed: 01/07/2023] Open
Abstract
Mitochondria are critical for the energetic demands of virtually every cellular process within nucleated eukaryotic cells. They harbour multiple copies of their own genome (mtDNA), as well as the protein-synthesing systems required for the translation of vital subunits of the oxidative phosphorylation machinery used to generate adenosine triphosphate (ATP). Molecular lesions to the mtDNA cause severe metabolic diseases and have been proposed to contribute to the progressive nature of common age-related diseases such as cancer, cardiomyopathy, diabetes, and neurodegenerative disorders. As a consequence of playing a central role in cellular energy metabolism, mitochondria produce reactive oxygen species (ROS) as a by-product of respiration. Here we review the evidence that mutations in the mtDNA exacerbate ROS production, contributing to disease.
Collapse
|
13
|
Hahn A, Zuryn S. The Cellular Mitochondrial Genome Landscape in Disease. Trends Cell Biol 2018; 29:227-240. [PMID: 30509558 DOI: 10.1016/j.tcb.2018.11.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 11/06/2018] [Accepted: 11/09/2018] [Indexed: 12/18/2022]
Abstract
Mitochondrial genome (mitochondrial DNA, mtDNA) lesions that unbalance bioenergetic and oxidative outputs are an important cause of human disease. A major impediment in our understanding of the pathophysiology of mitochondrial disorders is the complexity with which mtDNA mutations are spatiotemporally distributed and managed within individual cells, tissues, and organs. Unlike the comparatively static nuclear genome, accumulating evidence highlights the variability, dynamism, and modifiability of the mtDNA nucleotide sequence between individual cells over time. In this review, we summarize and discuss the impact of mtDNA defects on disease within the context of a mosaic and shifting mutational landscape.
Collapse
Affiliation(s)
- Anne Hahn
- The University of Queensland, Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research, Brisbane, Australia
| | - Steven Zuryn
- The University of Queensland, Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research, Brisbane, Australia.
| |
Collapse
|
14
|
Kapnick SM, Pacheco SE, McGuire PJ. The emerging role of immune dysfunction in mitochondrial diseases as a paradigm for understanding immunometabolism. Metabolism 2018; 81:97-112. [PMID: 29162500 PMCID: PMC5866745 DOI: 10.1016/j.metabol.2017.11.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 11/07/2017] [Accepted: 11/11/2017] [Indexed: 01/08/2023]
Abstract
Immunometabolism aims to define the role of intermediary metabolism in immune cell function, with bioenergetics and the mitochondria recently taking center stage. To date, the medical literature on mitochondria and immune function extols the virtues of mouse models in exploring this biologic intersection. While the laboratory mouse has become a standard for studying mammalian biology, this model comprises part of a comprehensive approach. Humans, with their broad array of inherited phenotypes, serve as a starting point for studying immunometabolism; specifically, patients with mitochondrial disease. Using this top-down approach, the mouse as a model organism facilitates further exploration of the consequences of mutations involved in mitochondrial maintenance and function. In this review, we will discuss the emerging phenotype of immune dysfunction in mitochondrial disease as a model for understanding the role of the mitochondria in immune function in available mouse models.
Collapse
Affiliation(s)
- Senta M Kapnick
- Metabolism, Infection and Immunity Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Susan E Pacheco
- Department of Pediatrics, The University of Texas Health Science Center, Houston, TX, USA
| | - Peter J McGuire
- Metabolism, Infection and Immunity Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA.
| |
Collapse
|
15
|
Cardiomyocyte hypertrophy induced by Endonuclease G deficiency requires reactive oxygen radicals accumulation and is inhibitable by the micropeptide humanin. Redox Biol 2018; 16:146-156. [PMID: 29502044 PMCID: PMC5952880 DOI: 10.1016/j.redox.2018.02.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Revised: 02/13/2018] [Accepted: 02/21/2018] [Indexed: 01/09/2023] Open
Abstract
The endonuclease G gene (Endog), which codes for a mitochondrial nuclease, was identified as a determinant of cardiac hypertrophy. How ENDOG controls cardiomyocyte growth is still unknown. Thus, we aimed at finding the link between ENDOG activity and cardiomyocyte growth. Endog deficiency induced reactive oxygen species (ROS) accumulation and abnormal growth in neonatal rodent cardiomyocytes, altering the AKT-GSK3β and Class-II histone deacethylases (HDAC) signal transduction pathways. These effects were blocked by ROS scavengers. Lack of ENDOG reduced mitochondrial DNA (mtDNA) replication independently of ROS accumulation. Because mtDNA encodes several subunits of the mitochondrial electron transport chain, whose activity is an important source of cellular ROS, we investigated whether Endog deficiency compromised the expression and activity of the respiratory chain complexes but found no changes in these parameters nor in ATP content. MtDNA also codes for humanin, a micropeptide with possible metabolic functions. Nanomolar concentrations of synthetic humanin restored normal ROS levels and cell size in Endog-deficient cardiomyocytes. These results support the involvement of redox signaling in the control of cardiomyocyte growth by ENDOG and suggest a pathway relating mtDNA content to the regulation of cell growth probably involving humanin, which prevents reactive oxygen radicals accumulation and hypertrophy induced by Endog deficiency. Endog deficiency induces cardiomyocyte hypertrophy and superoxide accumulation. Hypertrophy induced by Endog deficiency requires ROS accumulation. ENDOG is involved in mtDNA replication independently of ROS accumulation. Electron Transport Chain activity is not affected by Endog deficiency. Humanin restricts ROS accumulation and blocks cardiomyocyte growth.
Collapse
|
16
|
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.
Collapse
Affiliation(s)
- José Marín-García
- The Molecular Cardiology and Neuromuscular Institute, 75 Raritan Avenue, Highland Park, NJ, 08904, USA.
| |
Collapse
|
17
|
Knez J, Lakota K, Božič N, Okrajšek R, Cauwenberghs N, Thijs L, Kneževič I, Vrtovec B, Tomšič M, Čučnik S, Sodin-Šemrl S, Kuznetsova T, Brguljan-Hitij J. Correlation Between Mitochondrial DNA Content Measured in Myocardium and Peripheral Blood of Patients with Non-Ischemic Heart Failure. Genet Test Mol Biomarkers 2017; 21:736-741. [PMID: 29087733 DOI: 10.1089/gtmb.2017.0099] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND/OBJECTIVES Heart failure (HF) is associated with disturbances in mitochondrial energy production. This mitochondrial dysfunction is reflected by depletion of mitochondrial DNA (mtDNA) in different tissues. Our aims were to determine if there was a correlation between mtDNA content measured in myocardial tissue and the easily accessible peripheral blood cells of patients with non-ischemic HF; and to determine if there was a correlation between myocardial mtDNA and left ventricular (LV) ejection fraction. METHODS We prospectively collected paired myocardial tissue and peripheral blood samples from 13 consecutive end-stage non-ischemic HF patients undergoing cardiac transplantation. mtDNA content was assessed with real-time quantitative PCR by calculating the relative ratio of two specific mitochondrial sequences and one nuclear control gene sequence. RESULTS HF patients with lower myocardial mtDNA content had a significantly lower LV ejection fraction (r = 0.65, p = 0.016). Peripheral blood mtDNA content correlated positively with right ventricular myocardial mtDNA content (r = 0.63, p = 0.021). We also observed that averaged myocardial DNA content tended to correlate with peripheral blood mtDNA content (r = 0.53, p = 0.061). CONCLUSIONS In non-ischemic HF patients, myocardial mtDNA content is positively correlated with peripheral blood mtDNA content and LV function as assessed by echocardiography.
Collapse
Affiliation(s)
- Judita Knez
- 1 Division of Internal Medicine, Department of Hypertension, University Medical Centre Ljubljana , Ljubljana, Slovenia
- 2 Research Unit Hypertension and Cardiovascular Epidemiology, KU Leuven Department of Cardiovascular Sciences, University of Leuven , Leuven, Belgium
| | - Katja Lakota
- 3 Division of Internal Medicine, Department of Rheumatology, University Medical Centre Ljubljana , Ljubljana, Slovenia
| | - Nina Božič
- 1 Division of Internal Medicine, Department of Hypertension, University Medical Centre Ljubljana , Ljubljana, Slovenia
| | - Renata Okrajšek
- 4 Division of Internal Medicine, Department of Cardiology, University Medical Centre Ljubljana , Ljubljana, Slovenia
| | - Nicholas Cauwenberghs
- 2 Research Unit Hypertension and Cardiovascular Epidemiology, KU Leuven Department of Cardiovascular Sciences, University of Leuven , Leuven, Belgium
| | - Lutgarde Thijs
- 2 Research Unit Hypertension and Cardiovascular Epidemiology, KU Leuven Department of Cardiovascular Sciences, University of Leuven , Leuven, Belgium
| | - Ivan Kneževič
- 5 Division of Surgery, Department of Cardiovascular Surgery, University Medical Centre Ljubljana , Ljubljana, Slovenia
| | - Bojan Vrtovec
- 4 Division of Internal Medicine, Department of Cardiology, University Medical Centre Ljubljana , Ljubljana, Slovenia
| | - Matija Tomšič
- 3 Division of Internal Medicine, Department of Rheumatology, University Medical Centre Ljubljana , Ljubljana, Slovenia
| | - Saša Čučnik
- 3 Division of Internal Medicine, Department of Rheumatology, University Medical Centre Ljubljana , Ljubljana, Slovenia
| | - Snežna Sodin-Šemrl
- 3 Division of Internal Medicine, Department of Rheumatology, University Medical Centre Ljubljana , Ljubljana, Slovenia
| | - Tatiana Kuznetsova
- 2 Research Unit Hypertension and Cardiovascular Epidemiology, KU Leuven Department of Cardiovascular Sciences, University of Leuven , Leuven, Belgium
| | - Jana Brguljan-Hitij
- 1 Division of Internal Medicine, Department of Hypertension, University Medical Centre Ljubljana , Ljubljana, Slovenia
| |
Collapse
|
18
|
Kasahara T, Ishiwata M, Kakiuchi C, Fuke S, Iwata N, Ozaki N, Kunugi H, Minabe Y, Nakamura K, Iwata Y, Fujii K, Kanba S, Ujike H, Kusumi I, Kataoka M, Matoba N, Takata A, Iwamoto K, Yoshikawa T, Kato T. Enrichment of deleterious variants of mitochondrial DNA polymerase gene (POLG1) in bipolar disorder. Psychiatry Clin Neurosci 2017; 71:518-529. [PMID: 27987238 DOI: 10.1111/pcn.12496] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 11/15/2016] [Accepted: 12/06/2016] [Indexed: 12/13/2022]
Abstract
AIM Rare missense variants, which likely account for a substantial portion of the genetic 'dark matter' for a common complex disease, are challenging because the impacts of variants on disease development are difficult to substantiate. This study aimed to examine the impacts of amino acid substitution variants in the POLG1 found in bipolar disorder, as an example and proof of concept, in three different modalities of assessment: in silico predictions, in vitro biochemical assays, and clinical evaluation. We then tested whether deleterious variants in POLG1 contributed to the genetics of bipolar disorder. METHODS We searched for variants in the POLG1 gene in 796 Japanese patients with bipolar disorder and 767 controls and comprehensively investigated all 23 identified variants in the three modalities of assessment. POLG1 encodes mitochondrial DNA polymerase and is one of the causative genes for a Mendelian-inheritance mitochondrial disease, which is occasionally accompanied by mood disorders. The healthy control data from the Tohoku Medical Megabank Organization were also employed. RESULTS Although the frequency of carriers of deleterious variants varied from one method to another, every assessment achieved the same conclusion that deleterious POLG1 variants were significantly enriched in the variants identified in patients with bipolar disorder compared to those in controls. CONCLUSION Together with mitochondrial dysfunction in bipolar disorder, the present results suggested deleterious POLG1 variants as a credible risk for the multifactorial disease.
Collapse
Affiliation(s)
- Takaoki Kasahara
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Wako, Japan
| | - Mizuho Ishiwata
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Wako, Japan
| | - Chihiro Kakiuchi
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Wako, Japan
| | - Satoshi Fuke
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Wako, Japan
| | - Nakao Iwata
- Faculty of Medicine, Department of Psychiatry, Fujita Health University, Japan
| | - Norio Ozaki
- Faculty of Medicine, Department of Psychiatry, Nagoya University, Nagoya, Japan
| | - Hiroshi Kunugi
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Yoshio Minabe
- Department of Psychiatry and Neurology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Kazuhiko Nakamura
- Department of Psychiatry and Neurology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Yasuhide Iwata
- Department of Psychiatry and Neurology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Kumiko Fujii
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Wako, Japan.,Department of Psychiatry, Dokkyo Medical University School of Medicine, Mibu, Japan
| | - Shigenobu Kanba
- Department of Psychiatry, Kyushu University School of Medicine, Fukuoka, Japan
| | - Hiroshi Ujike
- Department of Psychiatry, Okayama University School of Medicine, Okayama, Japan
| | - Ichiro Kusumi
- Department of Psychiatry, Hokkaido University School of Medicine, Sapporo, Japan
| | - Muneko Kataoka
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Wako, Japan
| | - Nana Matoba
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Wako, Japan
| | - Atsushi Takata
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Wako, Japan
| | - Kazuya Iwamoto
- Department of Molecular Brain Science, Graduate School of Medicine, Kumamoto University, Kumamoto, Japan
| | - Takeo Yoshikawa
- Laboratory for Molecular Psychiatry, RIKEN Brain Science Institute, Wako, Japan
| | - Tadafumi Kato
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Wako, Japan
| |
Collapse
|
19
|
De Luise M, Girolimetti G, Okere B, Porcelli AM, Kurelac I, Gasparre G. Molecular and metabolic features of oncocytomas: Seeking the blueprints of indolent cancers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:591-601. [DOI: 10.1016/j.bbabio.2017.01.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 12/28/2016] [Accepted: 01/17/2017] [Indexed: 02/07/2023]
|
20
|
Chan SSL. Inherited mitochondrial genomic instability and chemical exposures. Toxicology 2017; 391:75-83. [PMID: 28756246 DOI: 10.1016/j.tox.2017.07.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 06/12/2017] [Accepted: 07/24/2017] [Indexed: 12/21/2022]
Abstract
There are approximately 1500 proteins that are needed for mitochondrial structure and function, most of which are encoded in the nuclear genome (Calvo et al., 2006). Each mitochondrion has its own genome (mtDNA), which in humans encodes 13 polypeptides, 22 tRNAs and 2 rRNAs required for oxidative phosphorylation. The mitochondrial genome of humans and most vertebrates is approximately 16.5kbp, double-stranded, circular, with few non-coding bases. Thus, maintaining mtDNA stability, that is, the ability of the cell to maintain adequate levels of mtDNA template for oxidative phosphorylation is essential and can be impacted by the level of mtDNA mutation currently within the cell or mitochondrion, but also from errors made during normal mtDNA replication, defects in mitochondrial quality control mechanisms, and exacerbated by exposures to exogenous and/or endogenous genotoxic agents. In this review, we expand on the origins and consequences of mtDNA instability, the current state of research regarding the mechanisms by which mtDNA instability can be overcome by cellular and chemical interventions, and the future of research and treatments for mtDNA instability.
Collapse
Affiliation(s)
- Sherine S L Chan
- Drug Discovery and Biomedical Sciences, College of Pharmacy, Medical University of South Carolina, Charleston, SC 29425, United States; Neuroene Therapeutics, Mt. Pleasant, SC 29464, United States.
| |
Collapse
|
21
|
Siibak T, Clemente P, Bratic A, Bruhn H, Kauppila TES, Macao B, Schober FA, Lesko N, Wibom R, Naess K, Nennesmo I, Wedell A, Peter B, Freyer C, Falkenberg M, Wredenberg A. A multi-systemic mitochondrial disorder due to a dominant p.Y955H disease variant in DNA polymerase gamma. Hum Mol Genet 2017; 26:2515-2525. [PMID: 28430993 PMCID: PMC5886115 DOI: 10.1093/hmg/ddx146] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 04/11/2017] [Indexed: 12/28/2022] Open
Abstract
Mutations in the mitochondrial DNA polymerase, POLG, are associated with a variety of clinical presentations, ranging from early onset fatal brain disease in Alpers syndrome to chronic progressive external ophthalmoplegia. The majority of mutations are linked with disturbances of mitochondrial DNA (mtDNA) integrity and maintenance. On a molecular level, depending on their location within the enzyme, mutations either lead to mtDNA depletion or the accumulation of multiple mtDNA deletions, and in some cases these molecular changes can be correlated to the clinical presentation. We identified a patient with a dominant p.Y955H mutation in POLG, presenting with a severe, early-onset multi-systemic mitochondrial disease with bilateral sensorineural hearing loss, cataract, myopathy, and liver failure. Using a combination of disease models of Drosophila melanogaster and in vitro biochemistry analysis, we compare the molecular consequences of the p.Y955H mutation to the well-documented p.Y955C mutation. We demonstrate that both mutations affect mtDNA replication and display a dominant negative effect, with the p.Y955H allele resulting in a more severe polymerase dysfunction.
Collapse
Affiliation(s)
- Triinu Siibak
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg SE-405?30, Sweden
| | - Paula Clemente
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Division of Metabolic Diseases, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, SE-171 77, Sweden.,Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm SE-171 77, Sweden
| | - Ana Bratic
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Cologne D-50931, Germany
| | - Helene Bruhn
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm SE-171 77, Sweden.,Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm SE-171 76, Sweden
| | - Timo E S Kauppila
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Cologne D-50931, Germany
| | - Bertil Macao
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg SE-405?30, Sweden
| | - Florian A Schober
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Division of Metabolic Diseases, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, SE-171 77, Sweden.,Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm SE-171 77, Sweden
| | - Nicole Lesko
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm SE-171 77, Sweden.,Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm SE-171 76, Sweden
| | - Rolf Wibom
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm SE-171 77, Sweden.,Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm SE-171 76, Sweden
| | - Karin Naess
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm SE-171 77, Sweden.,Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm SE-171 76, Sweden
| | - Inger Nennesmo
- Department of Pathology, Karolinska University Hospital, SE-171?77 Stockholm, Sweden
| | - Anna Wedell
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Division of Metabolic Diseases, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, SE-171 77, Sweden.,Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm SE-171 76, Sweden.,Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm SE-171 76, Sweden
| | - Bradley Peter
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg SE-405?30, Sweden
| | - Christoph Freyer
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Division of Metabolic Diseases, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, SE-171 77, Sweden.,Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm SE-171 77, Sweden.,Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm SE-171 76, Sweden
| | - Maria Falkenberg
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg SE-405?30, Sweden
| | - Anna Wredenberg
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Division of Metabolic Diseases, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, SE-171 77, Sweden.,Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm SE-171 77, Sweden.,Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm SE-171 76, Sweden
| |
Collapse
|
22
|
Kietzmann T, Petry A, Shvetsova A, Gerhold JM, Görlach A. The epigenetic landscape related to reactive oxygen species formation in the cardiovascular system. Br J Pharmacol 2017; 174:1533-1554. [PMID: 28332701 PMCID: PMC5446579 DOI: 10.1111/bph.13792] [Citation(s) in RCA: 146] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 03/06/2017] [Accepted: 03/08/2017] [Indexed: 02/06/2023] Open
Abstract
Cardiovascular diseases are among the leading causes of death worldwide. Reactive oxygen species (ROS) can act as damaging molecules but also represent central hubs in cellular signalling networks. Increasing evidence indicates that ROS play an important role in the pathogenesis of cardiovascular diseases, although the underlying mechanisms and consequences of pathophysiologically elevated ROS in the cardiovascular system are still not completely resolved. More recently, alterations of the epigenetic landscape, which can affect DNA methylation, post-translational histone modifications, ATP-dependent alterations to chromatin and non-coding RNA transcripts, have been considered to be of increasing importance in the pathogenesis of cardiovascular diseases. While it has long been accepted that epigenetic changes are imprinted during development or even inherited and are not changed after reaching the lineage-specific expression profile, it becomes more and more clear that epigenetic modifications are highly dynamic. Thus, they might provide an important link between the actions of ROS and cardiovascular diseases. This review will provide an overview of the role of ROS in modulating the epigenetic landscape in the context of the cardiovascular system. LINKED ARTICLES This article is part of a themed section on Redox Biology and Oxidative Stress in Health and Disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.12/issuetoc.
Collapse
Affiliation(s)
- Thomas Kietzmann
- Faculty of Biochemistry and Molecular Medicine, Biocenter OuluUniversity of OuluOuluFinland
| | - Andreas Petry
- Experimental and Molecular Pediatric CardiologyGerman Heart Center Munich at the TU MunichMunichGermany
- DZHK (German Centre for Cardiovascular Research)Partner Site Munich Heart AllianceMunichGermany
| | - Antonina Shvetsova
- Faculty of Biochemistry and Molecular Medicine, Biocenter OuluUniversity of OuluOuluFinland
| | - Joachim M Gerhold
- Institute of Molecular and Cell BiologyUniversity of TartuTartuEstonia
| | - Agnes Görlach
- Experimental and Molecular Pediatric CardiologyGerman Heart Center Munich at the TU MunichMunichGermany
- DZHK (German Centre for Cardiovascular Research)Partner Site Munich Heart AllianceMunichGermany
| |
Collapse
|
23
|
Nurminen A, Farnum GA, Kaguni LS. Pathogenicity in POLG syndromes: DNA polymerase gamma pathogenicity prediction server and database. BBA CLINICAL 2017; 7:147-156. [PMID: 28480171 PMCID: PMC5413197 DOI: 10.1016/j.bbacli.2017.04.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 04/11/2017] [Accepted: 04/12/2017] [Indexed: 12/19/2022]
Abstract
DNA polymerase gamma (POLG) is the replicative polymerase responsible for maintaining mitochondrial DNA (mtDNA). Disorders related to its functionality are a major cause of mitochondrial disease. The clinical spectrum of POLG syndromes includes Alpers-Huttenlocher syndrome (AHS), childhood myocerebrohepatopathy spectrum (MCHS), myoclonic epilepsy myopathy sensory ataxia (MEMSA), the ataxia neuropathy spectrum (ANS) and progressive external ophthalmoplegia (PEO). We have collected all publicly available POLG-related patient data and analyzed it using our pathogenic clustering model to provide a new research and clinical tool in the form of an online server. The server evaluates the pathogenicity of both previously reported and novel mutations. There are currently 176 unique point mutations reported and found in mitochondrial patients in the gene encoding the catalytic subunit of POLG, POLG. The mutations are distributed nearly uniformly along the length of the primary amino acid sequence of the gene. Our analysis shows that most of the mutations are recessive, and that the reported dominant mutations cluster within the polymerase active site in the tertiary structure of the POLG enzyme. The POLG Pathogenicity Prediction Server (http://polg.bmb.msu.edu) is targeted at clinicians and scientists studying POLG disorders, and aims to provide the most current available information regarding the pathogenicity of POLG mutations. Multi-level access to crucial data supporting diagnosis/prognosis of POLG syndromes Clustering protocol enables identification of novel neutral polymorphisms Identical alleles displaying variable symptoms evidence unidentified components POLG enzymes with premature stop codons, insertions/deletions group biochemically Dominant POLG mutations all lie within a critical location in the structure
Collapse
Key Words
- AHS, Alpers-Huttenlocher syndrome
- ANS, Ataxia neuropathy spectrum
- DNA polymerase gamma
- IP, Intrinsic processivity subdomain of POLGA spacer-domain
- MCHS, Childhood myocerebrohepatopathy spectrum
- MEMSA, Myoclonic epilepsy myopathy sensory ataxia
- Mitochondrial disorder
- Mutation database
- PDB ID, Four-character identification code for a protein structure in the RSCB PDB database
- PEO, Progressive external ophthalmoplegia
- PNF, Putatively non-functional enzyme
- POLG syndrome
- POLG, DNA polymerase gamma
- POLGA, Catalytic subunit of DNA polymerase gamma
- POLGB, Accessory subunit of DNA polymerase gamma
- Pathogenicity prediction
- Patient database
- SNP, Single nucleotide polymorphism/non-pathogenic mutation
Collapse
Affiliation(s)
- Anssi Nurminen
- Institute of Biosciences and Medical Technology, University of Tampere, Tampere, Finland
| | - Gregory A Farnum
- Department of Biochemistry and Molecular Biology and Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, MI, USA
| | - Laurie S Kaguni
- Institute of Biosciences and Medical Technology, University of Tampere, Tampere, Finland.,Department of Biochemistry and Molecular Biology and Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, MI, USA
| |
Collapse
|
24
|
DeBalsi KL, Hoff KE, Copeland WC. Role of the mitochondrial DNA replication machinery in mitochondrial DNA mutagenesis, aging and age-related diseases. Ageing Res Rev 2017; 33:89-104. [PMID: 27143693 DOI: 10.1016/j.arr.2016.04.006] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 04/19/2016] [Accepted: 04/19/2016] [Indexed: 12/19/2022]
Abstract
As regulators of bioenergetics in the cell and the primary source of endogenous reactive oxygen species (ROS), dysfunctional mitochondria have been implicated for decades in the process of aging and age-related diseases. Mitochondrial DNA (mtDNA) is replicated and repaired by nuclear-encoded mtDNA polymerase γ (Pol γ) and several other associated proteins, which compose the mtDNA replication machinery. Here, we review evidence that errors caused by this replication machinery and failure to repair these mtDNA errors results in mtDNA mutations. Clonal expansion of mtDNA mutations results in mitochondrial dysfunction, such as decreased electron transport chain (ETC) enzyme activity and impaired cellular respiration. We address the literature that mitochondrial dysfunction, in conjunction with altered mitochondrial dynamics, is a major driving force behind aging and age-related diseases. Additionally, interventions to improve mitochondrial function and attenuate the symptoms of aging are examined.
Collapse
Affiliation(s)
- Karen L DeBalsi
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Kirsten E Hoff
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - William C Copeland
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA.
| |
Collapse
|
25
|
Peripheral Blood Mitochondrial DNA and Myocardial Function. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 982:347-358. [DOI: 10.1007/978-3-319-55330-6_19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
|
26
|
Pokrzywinski KL, Biel TG, Kryndushkin D, Rao VA. Therapeutic Targeting of the Mitochondria Initiates Excessive Superoxide Production and Mitochondrial Depolarization Causing Decreased mtDNA Integrity. PLoS One 2016; 11:e0168283. [PMID: 28030582 PMCID: PMC5193408 DOI: 10.1371/journal.pone.0168283] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 11/29/2016] [Indexed: 01/01/2023] Open
Abstract
Mitochondrial dysregulation is closely associated with excessive reactive oxygen species (ROS) production. Altered redox homeostasis has been implicated in the onset of several diseases including cancer. Mitochondrial DNA (mtDNA) and proteins are particularly sensitive to ROS as they are in close proximity to the respiratory chain (RC). Mitoquinone (MitoQ), a mitochondria-targeted redox agent, selectively damages breast cancer cells possibly through damage induced via enhanced ROS production. However, the effects of MitoQ and other triphenylphosphonium (TPP+) conjugated agents on cancer mitochondrial homeostasis remain unknown. The primary objective of this study was to determine the impact of mitochondria-targeted agent [(MTAs) conjugated to TPP+: mitoTEMPOL, mitoquinone and mitochromanol-acetate] on mitochondrial physiology and mtDNA integrity in breast (MDA-MB-231) and lung (H23) cancer cells. The integrity of the mtDNA was assessed by quantifying the degree of mtDNA fragmentation and copy number, as well as by measuring mitochondrial proteins essential to mtDNA stability and maintenance (TFAM, SSBP1, TWINKLE, POLG and POLRMT). Mitochondrial status was evaluated by measuring superoxide production, mitochondrial membrane depolarization, oxygen consumption, extracellular acidification and mRNA or protein levels of the RC complexes along with TCA cycle activity. In this study, we demonstrated that all investigated MTAs impair mitochondrial health and decrease mtDNA integrity in MDA-MB-231 and H23 cells. However, differences in the degree of mitochondrial damage and mtDNA degradation suggest unique properties among each MTA that may be cell line, dose and time dependent. Collectively, our study indicates the potential for TPP+ conjugated molecules to impair breast and lung cancer cells by targeting mitochondrial homeostasis.
Collapse
Affiliation(s)
- Kaytee L. Pokrzywinski
- Laboratory of Applied Biochemistry, Division of Biotechnology Research and Review III, Office of Biotechnology Products, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Thomas G. Biel
- Laboratory of Applied Biochemistry, Division of Biotechnology Research and Review III, Office of Biotechnology Products, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Dmitry Kryndushkin
- Laboratory of Applied Biochemistry, Division of Biotechnology Research and Review III, Office of Biotechnology Products, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - V. Ashutosh Rao
- Laboratory of Applied Biochemistry, Division of Biotechnology Research and Review III, Office of Biotechnology Products, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, United States of America
- * E-mail:
| |
Collapse
|
27
|
Young MJ, Copeland WC. Human mitochondrial DNA replication machinery and disease. Curr Opin Genet Dev 2016; 38:52-62. [PMID: 27065468 DOI: 10.1016/j.gde.2016.03.005] [Citation(s) in RCA: 129] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 03/03/2016] [Accepted: 03/08/2016] [Indexed: 12/21/2022]
Abstract
The human mitochondrial genome is replicated by DNA polymerase γ in concert with key components of the mitochondrial DNA (mtDNA) replication machinery. Defects in mtDNA replication or nucleotide metabolism cause deletions, point mutations, or depletion of mtDNA. The resulting loss of cellular respiration ultimately induces mitochondrial genetic diseases, including mtDNA depletion syndromes (MDS) such as Alpers or early infantile hepatocerebral syndromes, and mtDNA deletion disorders such as progressive external ophthalmoplegia, ataxia-neuropathy, or mitochondrial neurogastrointestinal encephalomyopathy. Here we review the current literature regarding human mtDNA replication and heritable disorders caused by genetic changes of the POLG, POLG2, Twinkle, RNASEH1, DNA2, and MGME1 genes.
Collapse
Affiliation(s)
- Matthew J Young
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, NC 27709, United States
| | - William C Copeland
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, NC 27709, United States.
| |
Collapse
|
28
|
Liou SH, Chen YC, Liao HY, Wang CJ, Chen JS, Lee HL. Increased levels of oxidative stress biomarkers in metal oxides nanomaterial-handling workers. Biomarkers 2016; 21:600-6. [DOI: 10.3109/1354750x.2016.1160432] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Saou-Hsing Liou
- National Institute of Environmental Health Sciences, National Health Research Institutes, Zhunan, Miaoli County, Taiwan
| | - Yu-Cheng Chen
- Department of Chemistry, Fu Jen Catholic University, New Taipei City, Taiwan
| | - Hui-Yi Liao
- National Institute of Environmental Health Sciences, National Health Research Institutes, Zhunan, Miaoli County, Taiwan
| | - Chien-Jen Wang
- National Institute of Environmental Health Sciences, National Health Research Institutes, Zhunan, Miaoli County, Taiwan
| | - Jhih-Sheng Chen
- Department of Chemistry, Fu Jen Catholic University, New Taipei City, Taiwan
| | - Hui-Ling Lee
- Department of Chemistry, Fu Jen Catholic University, New Taipei City, Taiwan
| |
Collapse
|
29
|
Koczor CA, Ludlow I, Fields E, Jiao Z, Ludaway T, Russ R, Lewis W. Mitochondrial polymerase gamma dysfunction and aging cause cardiac nuclear DNA methylation changes. Physiol Genomics 2016; 48:274-80. [PMID: 26757797 DOI: 10.1152/physiolgenomics.00099.2015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 01/08/2016] [Indexed: 11/22/2022] Open
Abstract
Cardiomyopathy (CM) is an intrinsic weakening of myocardium with contractile dysfunction and congestive heart failure (CHF). CHF has been postulated to result from decreased mitochondrial energy production and oxidative stress. Effects of decreased mitochondrial oxygen consumption also can accelerate with aging. We previously showed DNA methylation changes in human hearts with CM. This was associated with mitochondrial DNA depletion, being another molecular marker of CM. We examined the relationship between mitochondrial dysfunction and cardiac epigenetic DNA methylation changes in both young and old mice. We used genetically engineered C57Bl/6 mice transgenic for a cardiac-specific mutant of the mitochondrial polymerase-γ (termed Y955C). Y955C mice undergo left ventricular hypertrophy (LVH) at a young age (∼ 94 days old), and LVH decompensated to CHF at old age (∼ 255 days old). Results found 95 genes differentially expressed as a result of Y955C expression, while 4,452 genes were differentially expressed as a result of aging hearts. Moreover, cardiac DNA methylation patterns differed between Y955C (4,506 peaks with 68.5% hypomethylation) and aged hearts (73,286 peaks with 80.2% hypomethylated). Correlatively, of the 95 Y955C-dependent differentially expressed genes, 30 genes (31.6%) also displayed differential DNA methylation; in the 4,452 age-dependent differentially expressed genes, 342 genes (7.7%) displayed associated DNA methylation changes. Both Y955C and aging demonstrated significant enrichment of CACGTG-associated E-box motifs in differentially methylated regions. Cardiac mitochondrial polymerase dysfunction alters nuclear DNA methylation. Furthermore, aging causes a robust change in cardiac DNA methylation that is partially associated with mitochondrial polymerase dysfunction.
Collapse
Affiliation(s)
| | - Ivan Ludlow
- Department of Pathology, Emory University, Atlanta, Georgia
| | - Earl Fields
- Department of Pathology, Emory University, Atlanta, Georgia
| | - Zhe Jiao
- Department of Pathology, Emory University, Atlanta, Georgia
| | - Tomika Ludaway
- Department of Pathology, Emory University, Atlanta, Georgia
| | - Rodney Russ
- Department of Pathology, Emory University, Atlanta, Georgia
| | - William Lewis
- Department of Pathology, Emory University, Atlanta, Georgia
| |
Collapse
|
30
|
Rahn JJ, Bestman JE, Stackley KD, Chan SSL. Zebrafish lacking functional DNA polymerase gamma survive to juvenile stage, despite rapid and sustained mitochondrial DNA depletion, altered energetics and growth. Nucleic Acids Res 2015; 43:10338-52. [PMID: 26519465 PMCID: PMC4666367 DOI: 10.1093/nar/gkv1139] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 10/16/2015] [Indexed: 01/05/2023] Open
Abstract
DNA polymerase gamma (POLG) is essential for replication and repair of mitochondrial DNA (mtDNA). Mutations in POLG cause mtDNA instability and a diverse range of poorly understood human diseases. Here, we created a unique Polg animal model, by modifying polg within the critical and highly conserved polymerase domain in zebrafish. polg+/− offspring were indistinguishable from WT siblings in multiple phenotypic and biochemical measures. However, polg−/− mutants developed severe mtDNA depletion by one week post-fertilization (wpf), developed slowly and had regenerative defects, yet surprisingly survived up to 4 wpf. An in vivo mtDNA polymerase activity assay utilizing ethidium bromide (EtBr) to deplete mtDNA, showed that polg+/− and WT zebrafish fully recover mtDNA content two weeks post-EtBr removal. EtBr further reduced already low levels of mtDNA in polg−/− animals, but mtDNA content did not recover following release from EtBr. Despite significantly decreased respiration that corresponded with tissue-specific levels of mtDNA, polg−/− animals had WT levels of ATP and no increase in lactate. This zebrafish model of mitochondrial disease now provides unique opportunities for studying mtDNA instability from multiple angles, as polg−/− mutants can survive to juvenile stage, rather than lose viability in embryogenesis as seen in Polg mutant mice.
Collapse
Affiliation(s)
- Jennifer J Rahn
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Jennifer E Bestman
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Krista D Stackley
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Sherine S L Chan
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425, USA
| |
Collapse
|
31
|
Koczor CA, Fields E, Jedrzejczak MJ, Jiao Z, Ludaway T, Russ R, Shang J, Torres RA, Lewis W. Methamphetamine and HIV-Tat alter murine cardiac DNA methylation and gene expression. Toxicol Appl Pharmacol 2015; 288:409-19. [PMID: 26307267 DOI: 10.1016/j.taap.2015.08.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 07/13/2015] [Accepted: 08/19/2015] [Indexed: 11/18/2022]
Abstract
This study addresses the individual and combined effects of HIV-1 and methamphetamine (N-methyl-1-phenylpropan-2-amine, METH) on cardiac dysfunction in a transgenic mouse model of HIV/AIDS. METH is abused epidemically and is frequently associated with acquisition of HIV-1 infection or AIDS. We employed microarrays to identify mRNA differences in cardiac left ventricle (LV) gene expression following METH administration (10d, 3mg/kg/d, subcutaneously) in C57Bl/6 wild-type littermates (WT) and Tat-expressing transgenic (TG) mice. Arrays identified 880 differentially expressed genes (expression fold change>1.5, p<0.05) following METH exposure, Tat expression, or both. Using pathway enrichment analysis, mRNAs encoding polypeptides for calcium signaling and contractility were altered in the LV samples. Correlative DNA methylation analysis revealed significant LV DNA methylation changes following METH exposure and Tat expression. By combining these data sets, 38 gene promoters (27 related to METH, 11 related to Tat) exhibited differences by both methods of analysis. Among those, only the promoter for CACNA1C that encodes L-type calcium channel Cav1.2 displayed DNA methylation changes concordant with its gene expression change. Quantitative PCR verified that Cav1.2 LV mRNA abundance doubled following METH. Correlative immunoblots specific for Cav1.2 revealed a 3.5-fold increase in protein abundance in METH LVs. Data implicate Cav1.2 in calcium dysregulation and hypercontractility in the murine LV exposed to METH. They suggest a pathogenetic role for METH exposure to promote LV dysfunction that outweighs Tat-induced effects.
Collapse
Affiliation(s)
| | - Earl Fields
- Department of Pathology, Emory University, Atlanta, GA 30322, United States
| | - Mark J Jedrzejczak
- Department of Pathology, Emory University, Atlanta, GA 30322, United States
| | - Zhe Jiao
- Department of Pathology, Emory University, Atlanta, GA 30322, United States
| | - Tomika Ludaway
- Department of Pathology, Emory University, Atlanta, GA 30322, United States
| | - Rodney Russ
- Department of Pathology, Emory University, Atlanta, GA 30322, United States
| | - Joan Shang
- Department of Pathology, Emory University, Atlanta, GA 30322, United States
| | - Rebecca A Torres
- Department of Pathology, Emory University, Atlanta, GA 30322, United States
| | - William Lewis
- Department of Pathology, Emory University, Atlanta, GA 30322, United States
| |
Collapse
|
32
|
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]
|
33
|
Abstract
The ultrastructure of the cardiac myocyte is remarkable for the high density of mitochondria tightly packed between sarcomeres. This structural organization is designed to provide energy in the form of ATP to fuel normal pump function of the heart. A complex system comprised of regulatory factors and energy metabolic machinery, encoded by both mitochondrial and nuclear genomes, is required for the coordinate control of cardiac mitochondrial biogenesis, maturation, and high-capacity function. This process involves the action of a transcriptional regulatory network that builds and maintains the mitochondrial genome and drives the expression of the energy transduction machinery. This finely tuned system is responsive to developmental and physiological cues, as well as changes in fuel substrate availability. Deficiency of components critical for mitochondrial energy production frequently manifests as a cardiomyopathic phenotype, underscoring the requirement to maintain high respiration rates in the heart. Although a precise causative role is not clear, there is increasing evidence that perturbations in this regulatory system occur in the hypertrophied and failing heart. This review summarizes current knowledge and highlights recent advances in our understanding of the transcriptional regulatory factors and signaling networks that serve to regulate mitochondrial biogenesis and function in the mammalian heart.
Collapse
Affiliation(s)
- Rick B Vega
- From the Diabetes and Obesity Research Center, Cardiovascular Pathobiology Program, Sanford-Burnham Medical Research Institute, Orlando, FL
| | - Julie L Horton
- From the Diabetes and Obesity Research Center, Cardiovascular Pathobiology Program, Sanford-Burnham Medical Research Institute, Orlando, FL
| | - Daniel P Kelly
- From the Diabetes and Obesity Research Center, Cardiovascular Pathobiology Program, Sanford-Burnham Medical Research Institute, Orlando, FL.
| |
Collapse
|
34
|
Mitochondrial Oxidative Stress, Mitochondrial DNA Damage and Their Role in Age-Related Vascular Dysfunction. Int J Mol Sci 2015; 16:15918-53. [PMID: 26184181 PMCID: PMC4519931 DOI: 10.3390/ijms160715918] [Citation(s) in RCA: 171] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 06/17/2015] [Accepted: 06/29/2015] [Indexed: 02/06/2023] Open
Abstract
The prevalence of cardiovascular diseases is significantly increased in the older population. Risk factors and predictors of future cardiovascular events such as hypertension, atherosclerosis, or diabetes are observed with higher frequency in elderly individuals. A major determinant of vascular aging is endothelial dysfunction, characterized by impaired endothelium-dependent signaling processes. Increased production of reactive oxygen species (ROS) leads to oxidative stress, loss of nitric oxide (•NO) signaling, loss of endothelial barrier function and infiltration of leukocytes to the vascular wall, explaining the low-grade inflammation characteristic for the aged vasculature. We here discuss the importance of different sources of ROS for vascular aging and their contribution to the increased cardiovascular risk in the elderly population with special emphasis on mitochondrial ROS formation and oxidative damage of mitochondrial DNA. Also the interaction (crosstalk) of mitochondria with nicotinamide adenosine dinucleotide phosphate (NADPH) oxidases is highlighted. Current concepts of vascular aging, consequences for the development of cardiovascular events and the particular role of ROS are evaluated on the basis of cell culture experiments, animal studies and clinical trials. Present data point to a more important role of oxidative stress for the maximal healthspan (healthy aging) than for the maximal lifespan.
Collapse
|
35
|
Lauritzen KH, Kleppa L, Aronsen JM, Eide L, Carlsen H, Haugen ØP, Sjaastad I, Klungland A, Rasmussen LJ, Attramadal H, Storm-Mathisen J, Bergersen LH. Impaired dynamics and function of mitochondria caused by mtDNA toxicity leads to heart failure. Am J Physiol Heart Circ Physiol 2015; 309:H434-49. [PMID: 26055793 DOI: 10.1152/ajpheart.00253.2014] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 06/02/2015] [Indexed: 11/22/2022]
Abstract
Cardiac mitochondrial dysfunction has been implicated in heart failure of diverse etiologies. Generalized mitochondrial disease also leads to cardiomyopathy with various clinical manifestations. Impaired mitochondrial homeostasis may over time, such as in the aging heart, lead to cardiac dysfunction. Mitochondrial DNA (mtDNA), close to the electron transport chain and unprotected by histones, may be a primary pathogenetic site, but this is not known. Here, we test the hypothesis that cumulative damage of cardiomyocyte mtDNA leads to cardiomyopathy and heart failure. Transgenic mice with Tet-on inducible, cardiomyocyte-specific expression of a mutant uracil-DNA glycosylase 1 (mutUNG1) were generated. The mutUNG1 is known to remove thymine in addition to uracil from the mitochondrial genome, generating apyrimidinic sites, which obstruct mtDNA function. Following induction of mutUNG1 in cardiac myocytes by administering doxycycline, the mice developed hypertrophic cardiomyopathy, leading to congestive heart failure and premature death after ∼2 mo. The heart showed reduced mtDNA replication, severely diminished mtDNA transcription, and suppressed mitochondrial respiration with increased Pgc-1α, mitochondrial mass, and antioxidative defense enzymes, and finally failing mitochondrial fission/fusion dynamics and deteriorating myocardial contractility as the mechanism of heart failure. The approach provides a model with induced cardiac-restricted mtDNA damage for investigation of mtDNA-based heart disease.
Collapse
Affiliation(s)
- Knut H Lauritzen
- Department of Oral Biology, Brain and Muscle Energy Group, University of Oslo, Oslo, Norway; Department of Anatomy, Institute of Basic Medical Sciences, and Healthy Brain Ageing Centre, University of Oslo, Oslo, Norway
| | - Liv Kleppa
- Department of Oral Biology, Brain and Muscle Energy Group, University of Oslo, Oslo, Norway; Department of Anatomy, Institute of Basic Medical Sciences, and Healthy Brain Ageing Centre, University of Oslo, Oslo, Norway
| | - Jan Magnus Aronsen
- Institute for Experimental Medical Research, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway; KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Norway, Oslo, Norway
| | - Lars Eide
- Department of Medical Biochemistry, University of Oslo, Oslo, Norway
| | - Harald Carlsen
- Department of Nutrition Research, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Øyvind P Haugen
- Department of Oral Biology, Brain and Muscle Energy Group, University of Oslo, Oslo, Norway; Department of Anatomy, Institute of Basic Medical Sciences, and Healthy Brain Ageing Centre, University of Oslo, Oslo, Norway
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway; KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Norway, Oslo, Norway
| | - Arne Klungland
- Department of Nutrition Research, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway; Institute of Medical Microbiology, Oslo University Hospital, Oslo, Norway
| | - Lene Juel Rasmussen
- Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark; Department of Cellular and Molecular Medicine, University of Copenhagen, Denmark
| | - Håvard Attramadal
- Institute for Surgical Research, Oslo University Hospital, Oslo, Norway; and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Jon Storm-Mathisen
- Department of Anatomy, Institute of Basic Medical Sciences, and Healthy Brain Ageing Centre, University of Oslo, Oslo, Norway
| | - Linda H Bergersen
- Department of Oral Biology, Brain and Muscle Energy Group, University of Oslo, Oslo, Norway; Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark;
| |
Collapse
|
36
|
Szczepanowska K, Trifunovic A. Different faces of mitochondrial DNA mutators. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:1362-72. [PMID: 26014346 DOI: 10.1016/j.bbabio.2015.05.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Revised: 05/15/2015] [Accepted: 05/17/2015] [Indexed: 10/23/2022]
Abstract
A number of studies have shown that ageing is associated with increased amounts of mtDNA deletions and/or point mutations in a variety of species as diverse as Caenorhabditis elegans, Drosophila melanogaster, mice, rats, dogs, primates and humans. This detected vulnerability of mtDNA has led to the suggestion that the accumulation of somatic mtDNA mutations might arise from increased oxidative damage and could play an important role in the ageing process by producing cells with a decreased oxidative capacity. However, the vast majority of DNA polymorphisms and disease-causing base-substitution mutations and age-associated mutations that have been detected in human mtDNA are transition mutations. They are likely arising from the slight infidelity of the mitochondrial DNA polymerase. Indeed, transition mutations are also the predominant type of mutation found in mtDNA mutator mice, a model for premature ageing caused by increased mutation load due to the error prone mitochondrial DNA synthesis. These particular misincorporation events could also be exacerbated by dNTP pool imbalances. The role of different repair, replication and maintenance mechanisms that contribute to mtDNA integrity and mutagenesis will be discussed in details in this article. This article is part of a Special Issue entitled: Mitochondrial Dysfunction in Aging.
Collapse
Affiliation(s)
- Karolina Szczepanowska
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Institute for Mitochondrial Diseases and Ageing, Medical Faculty, University of Cologne, D-50931 Cologne, Germany
| | - Aleksandra Trifunovic
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Institute for Mitochondrial Diseases and Ageing, Medical Faculty, University of Cologne, D-50931 Cologne, Germany.
| |
Collapse
|
37
|
Lodi T, Dallabona C, Nolli C, Goffrini P, Donnini C, Baruffini E. DNA polymerase γ and disease: what we have learned from yeast. Front Genet 2015; 6:106. [PMID: 25852747 PMCID: PMC4362329 DOI: 10.3389/fgene.2015.00106] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 03/02/2015] [Indexed: 11/16/2022] Open
Abstract
Mip1 is the Saccharomyces cerevisiae DNA polymerase γ (Pol γ), which is responsible for the replication of mitochondrial DNA (mtDNA). It belongs to the family A of the DNA polymerases and it is orthologs to human POLGA. In humans, mutations in POLG(1) cause many mitochondrial pathologies, such as progressive external ophthalmoplegia (PEO), Alpers' syndrome, and ataxia-neuropathy syndrome, all of which present instability of mtDNA, which results in impaired mitochondrial function in several tissues with variable degrees of severity. In this review, we summarize the genetic and biochemical knowledge published on yeast mitochondrial DNA polymerase from 1989, when the MIP1 gene was first cloned, up until now. The role of yeast is particularly emphasized in (i) validating the pathological mutations found in human POLG and modeled in MIP1, (ii) determining the molecular defects caused by these mutations and (iii) finding the correlation between mutations/polymorphisms in POLGA and mtDNA toxicity induced by specific drugs. We also describe recent findings regarding the discovery of molecules able to rescue the phenotypic defects caused by pathological mutations in Mip1, and the construction of a model system in which the human Pol γ holoenzyme is expressed in yeast and complements the loss of Mip1.
Collapse
Affiliation(s)
- Tiziana Lodi
- Department of Life Sciences, University of Parma Parma, Italy
| | | | - Cecilia Nolli
- Department of Life Sciences, University of Parma Parma, Italy
| | - Paola Goffrini
- Department of Life Sciences, University of Parma Parma, Italy
| | - Claudia Donnini
- Department of Life Sciences, University of Parma Parma, Italy
| | | |
Collapse
|
38
|
Iommarini L, Peralta S, Torraco A, Diaz F. Mitochondrial Diseases Part II: Mouse models of OXPHOS deficiencies caused by defects in regulatory factors and other components required for mitochondrial function. Mitochondrion 2015; 22:96-118. [PMID: 25640959 DOI: 10.1016/j.mito.2015.01.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 01/22/2015] [Indexed: 01/21/2023]
Abstract
Mitochondrial disorders are defined as defects that affect the oxidative phosphorylation system (OXPHOS). They are characterized by a heterogeneous array of clinical presentations due in part to a wide variety of factors required for proper function of the components of the OXPHOS system. There is no cure for these disorders owing to our poor knowledge of the pathogenic mechanisms of disease. To understand the mechanisms of human disease numerous mouse models have been developed in recent years. Here we summarize the features of several mouse models of mitochondrial diseases directly related to those factors affecting mtDNA maintenance, replication, transcription, translation as well as other proteins that are involved in mitochondrial dynamics and quality control which affect mitochondrial OXPHOS function without being intrinsic components of the system. We discuss how these models have contributed to our understanding of mitochondrial diseases and their pathogenic mechanisms.
Collapse
Affiliation(s)
- Luisa Iommarini
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Via Irnerio 42, 40128 Bologna, Italy.
| | - Susana Peralta
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
| | - Alessandra Torraco
- Unit for Neuromuscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital, IRCCS, Viale di San Paolo, 15 - 00146, Rome, Italy.
| | - Francisca Diaz
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
| |
Collapse
|
39
|
Stumpf JD, Copeland WC. MMS exposure promotes increased MtDNA mutagenesis in the presence of replication-defective disease-associated DNA polymerase γ variants. PLoS Genet 2014; 10:e1004748. [PMID: 25340760 PMCID: PMC4207668 DOI: 10.1371/journal.pgen.1004748] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 09/11/2014] [Indexed: 11/18/2022] Open
Abstract
Mitochondrial DNA (mtDNA) encodes proteins essential for ATP production. Mutant variants of the mtDNA polymerase cause mutagenesis that contributes to aging, genetic diseases, and sensitivity to environmental agents. We interrogated mtDNA replication in Saccharomyces cerevisiae strains with disease-associated mutations affecting conserved regions of the mtDNA polymerase, Mip1, in the presence of the wild type Mip1. Mutant frequency arising from mtDNA base substitutions that confer erythromycin resistance and deletions between 21-nucleotide direct repeats was determined. Previously, increased mutagenesis was observed in strains encoding mutant variants that were insufficient to maintain mtDNA and that were not expected to reduce polymerase fidelity or exonuclease proofreading. Increased mutagenesis could be explained by mutant variants stalling the replication fork, thereby predisposing the template DNA to irreparable damage that is bypassed with poor fidelity. This hypothesis suggests that the exogenous base-alkylating agent, methyl methanesulfonate (MMS), would further increase mtDNA mutagenesis. Mitochondrial mutagenesis associated with MMS exposure was increased up to 30-fold in mip1 mutants containing disease-associated alterations that affect polymerase activity. Disrupting exonuclease activity of mutant variants was not associated with increased spontaneous mutagenesis compared with exonuclease-proficient alleles, suggesting that most or all of the mtDNA was replicated by wild type Mip1. A novel subset of C to G transversions was responsible for about half of the mutants arising after MMS exposure implicating error-prone bypass of methylated cytosines as the predominant mutational mechanism. Exposure to MMS does not disrupt exonuclease activity that suppresses deletions between 21-nucleotide direct repeats, suggesting the MMS-induce mutagenesis is not explained by inactivated exonuclease activity. Further, trace amounts of CdCl2 inhibit mtDNA replication but suppresses MMS-induced mutagenesis. These results suggest a novel mechanism wherein mutations that lead to hypermutation by DNA base-damaging agents and associate with mitochondrial disease may contribute to previously unexplained phenomena, such as the wide variation of age of disease onset and acquired mitochondrial toxicities. Thousands of mitochondrial DNA (mtDNA) per cell are necessary to maintain energy required for cellular survival in humans. Interfering with the mtDNA polymerase can result in mitochondrial diseases and mitochondrial toxicity. Therefore, it is important to explore new genetic and environmental mechanisms that alter the effectiveness and accuracy of mtDNA replication. This genetic study uses the budding yeast to demonstrate that heterozygous strains harboring disease-associated mutations in the mtDNA polymerase gene in the presence of a wild type copy of the mtDNA polymerase are associated with increased mtDNA point mutagenesis in the presence of methane methylsulfonate, a known base damaging agent. Further observations suggest that the inability of disease-associated variants to replicate mtDNA resulted in increased vulnerability to irreparable base damage that was likely to result in mutations when replicated. Also, this study showed that trace amounts of the environmental contaminant cadmium chloride impairs mtDNA replication but eliminates damage-induced mutagenesis in the remaining functional mitochondria. This interplay between disease-associated variant and wild type polymerase offers new insights on possible disease variation and implicates novel environmental consequences for compound heterozygous patients.
Collapse
Affiliation(s)
- Jeffrey D. Stumpf
- Mitochondrial DNA Replication Group, Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, North Carolina, United States of America
| | - William C. Copeland
- Mitochondrial DNA Replication Group, Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, North Carolina, United States of America
- * E-mail:
| |
Collapse
|
40
|
López S, Buil A, Souto JC, Casademont J, Martinez-Perez A, Almasy L, Soria JM. A genome-wide association study in the genetic analysis of idiopathic thrombophilia project suggests sex-specific regulation of mitochondrial DNA levels. Mitochondrion 2014; 18:34-40. [PMID: 25240745 DOI: 10.1016/j.mito.2014.09.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 08/24/2014] [Accepted: 09/10/2014] [Indexed: 12/20/2022]
Abstract
Identifying genes that regulate mitochondrial DNA (mtDNA) levels is of interest due to an increasing number of diseases in humans that are associated with altered mtDNA levels. We searched for nuclear polymorphisms that influence mtDNA levels using a family-based genome-wide association (GWAS) method. Also, our aim was to determine if sex influences the genetic control of mtDNA levels. Two intron-polymorphisms, in the genes PARK2 and MRPL37, showed a tendency toward an association with mtDNA levels only in females and only in males, respectively. Both genes have a role in mitochondrial biogenesis and are potential candidates for the sex-specific control of mtDNA levels.
Collapse
Affiliation(s)
- Sonia López
- Unit of Genomic of Complex Diseases, Research Institute of Hospital de la Santa Creu i Sant Pau, Barcelona, Spain.
| | - Alfonso Buil
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva, Switzerland
| | - Juan Carlos Souto
- Haemostasis and Thrombosis Unit, Department of Haematology, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Jordi Casademont
- Internal Medicine Department, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Angel Martinez-Perez
- Unit of Genomic of Complex Diseases, Research Institute of Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Laura Almasy
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - José Manuel Soria
- Unit of Genomic of Complex Diseases, Research Institute of Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| |
Collapse
|
41
|
Abstract
Mitochondrial DNA is replicated by DNA polymerase γ in concert with accessory proteins such as the mitochondrial DNA helicase, single-stranded DNA binding protein, topoisomerase, and initiating factors. Defects in mitochondrial DNA replication or nucleotide metabolism can cause mitochondrial genetic diseases due to mitochondrial DNA deletions, point mutations, or depletion, which ultimately cause loss of oxidative phosphorylation. These genetic diseases include mitochondrial DNA depletion syndromes such as Alpers or early infantile hepatocerebral syndromes, and mitochondrial DNA deletion disorders, such as progressive external ophthalmoplegia, ataxia-neuropathy, or mitochondrial neurogastrointestinal encephalomyopathy. This review focuses on our current knowledge of genetic defects of mitochondrial DNA replication (POLG, POLG2, C10orf2, and MGME1) that cause instability of mitochondrial DNA and mitochondrial disease.
Collapse
Affiliation(s)
- William C. Copeland
- Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
| |
Collapse
|
42
|
Pagano G, Aiello Talamanca A, Castello G, Cordero MD, d'Ischia M, Gadaleta MN, Pallardó FV, Petrović S, Tiano L, Zatterale A. Oxidative stress and mitochondrial dysfunction across broad-ranging pathologies: toward mitochondria-targeted clinical strategies. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2014; 2014:541230. [PMID: 24876913 PMCID: PMC4024404 DOI: 10.1155/2014/541230] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 02/24/2014] [Indexed: 02/07/2023]
Abstract
Beyond the disorders recognized as mitochondrial diseases, abnormalities in function and/or ultrastructure of mitochondria have been reported in several unrelated pathologies. These encompass ageing, malformations, and a number of genetic or acquired diseases, as diabetes and cardiologic, haematologic, organ-specific (e.g., eye or liver), neurologic and psychiatric, autoimmune, and dermatologic disorders. The mechanistic grounds for mitochondrial dysfunction (MDF) along with the occurrence of oxidative stress (OS) have been investigated within the pathogenesis of individual disorders or in groups of interrelated disorders. We attempt to review broad-ranging pathologies that involve mitochondrial-specific deficiencies or rely on cytosol-derived prooxidant states or on autoimmune-induced mitochondrial damage. The established knowledge in these subjects warrants studies aimed at elucidating several open questions that are highlighted in the present review. The relevance of OS and MDF in different pathologies may establish the grounds for chemoprevention trials aimed at compensating OS/MDF by means of antioxidants and mitochondrial nutrients.
Collapse
Affiliation(s)
- Giovanni Pagano
- Cancer Research Centre at Mercogliano (CROM), Istituto Nazionale Tumori Fondazione G. Pascale-IRCCS, 80131 Naples, Italy
| | - Annarita Aiello Talamanca
- Cancer Research Centre at Mercogliano (CROM), Istituto Nazionale Tumori Fondazione G. Pascale-IRCCS, 80131 Naples, Italy
| | - Giuseppe Castello
- Cancer Research Centre at Mercogliano (CROM), Istituto Nazionale Tumori Fondazione G. Pascale-IRCCS, 80131 Naples, Italy
| | - Mario D. Cordero
- Research Laboratory, Dental School, Sevilla University, 41009 Sevilla, Spain
| | - Marco d'Ischia
- Department of Chemical Sciences, Federico II University, 80126 Naples, Italy
| | - Maria Nicola Gadaleta
- National Research Council, Institute of Biomembranes and Bioenergetics, 70126 Bari, Italy
| | | | - Sandra Petrović
- “Vinca” Institute of Nuclear Sciences, University of Belgrade, 11070 Belgrade, Serbia
| | - Luca Tiano
- Department of Clinical and Dental Sciences, Polytechnical University of Marche, 60100 Ancona, Italy
| | | |
Collapse
|
43
|
Abstract
Human mitochondria harbor an essential, high copy number, 16,569 base pair, circular DNA genome that encodes 13 gene products required for electron transport and oxidative phosphorylation. Mutation of this genome can compromise cellular respiration, ultimately resulting in a variety of progressive metabolic diseases collectively known as 'mitochondrial diseases'. Mutagenesis of mtDNA and the persistence of mtDNA mutations in cells and tissues is a complex topic, involving the interplay of DNA replication, DNA damage and repair, purifying selection, organelle dynamics, mitophagy, and aging. We briefly review these general elements that affect maintenance of mtDNA, and we focus on nuclear genes encoding the mtDNA replication machinery that can perturb the genetic integrity of the mitochondrial genome.
Collapse
Affiliation(s)
- William C Copeland
- Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, Durham, NC 27709, USA.
| | - Matthew J Longley
- Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, Durham, NC 27709, USA
| |
Collapse
|
44
|
Meng X, Suo X, Ding W, Li X, Ding Y. Determination of 8-hydroxy-2′- deoxyguanosine derivatized with 4-chloro-7- nitrobenzofurazan in urine by CE-LIF. Electrophoresis 2014; 35:1873-9. [DOI: 10.1002/elps.201300650] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 02/24/2014] [Accepted: 03/07/2014] [Indexed: 12/30/2022]
Affiliation(s)
- Xiangying Meng
- College of Life Sciences; University of Chinese Academy of Sciences; Beijing P. R. China
| | - Xingmei Suo
- School of Information Engineering; Minzu University of China; Beijing P. R. China
| | - Wenjun Ding
- College of Life Sciences; University of Chinese Academy of Sciences; Beijing P. R. China
| | - Xiangjun Li
- School of Chemistry and Chemical Engineering; University of Chinese Academy of Sciences; Beijing P. R. China
| | - Yongsheng Ding
- College of Life Sciences; University of Chinese Academy of Sciences; Beijing P. R. China
| |
Collapse
|
45
|
Aging and HIV/AIDS: pathogenetic role of therapeutic side effects. J Transl Med 2014; 94:120-8. [PMID: 24336070 PMCID: PMC4144856 DOI: 10.1038/labinvest.2013.142] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 10/17/2013] [Accepted: 10/22/2013] [Indexed: 12/22/2022] Open
Abstract
The intersection of aging and HIV/AIDS is a looming 'epidemic within an epidemic.' This paper reviews how HIV/AIDS and its therapy cause premature aging or contribute mechanistically to HIV-associated non-AIDS illnesses (HANA). Survival with HIV/AIDS has markedly improved by therapy combinations containing nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors, and protease inhibitors (PIs) called HAART (highly active antiretroviral therapy). Because NRTIs and PIs together prevent or attenuate HIV-1 replication, and prolong life, the population of aging patients with HIV/AIDS increases accordingly. However, illnesses frequently associated with aging in the absence of HIV/AIDS appear to occur prematurely in HIV/AIDS patients. Theories that help to explain biological aging include oxidative stress (where mitochondrial oxidative injury exceeds antioxidant defense), chromosome telomere shortening with associated cellular senescence, and accumulation of lamin A precursors (a nuclear envelop protein). Each of these has the potential to be enhanced or caused by HIV/AIDS, antiretroviral therapy, or both. Antiretroviral therapy has been shown to enhance events seen in biological aging. Specifically, antiretroviral NRTIs cause mitochondrial dysfunction, oxidative stress, and mitochondrial DNA defects that resemble features of both HANA and aging. More recent clinical evidence points to telomere shortening caused by NRTI triphosphate-induced inhibition of telomerase, suggesting telomerase reverse transcriptase (TERT) inhibition as being a pathogenetic contributor to premature aging in HIV/AIDS. PIs may also have a role in premature aging in HIV/AIDS as they cause prelamin A accumulation. Overall, toxic side effects of HAART may both resemble and promote events of aging and are worthy of mechanistic studies.
Collapse
|
46
|
Koczor CA, Torres RA, Fields EJ, Boyd A, He S, Patel N, Lee EK, Samarel AM, Lewis W. Thymidine kinase and mtDNA depletion in human cardiomyopathy: epigenetic and translational evidence for energy starvation. Physiol Genomics 2013; 45:590-6. [PMID: 23695887 DOI: 10.1152/physiolgenomics.00014.2013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
This study addresses how depletion of human cardiac left ventricle (LV) mitochondrial DNA (mtDNA) and epigenetic nuclear DNA methylation promote cardiac dysfunction in human dilated cardiomyopathy (DCM) through regulation of pyrimidine nucleotide kinases. Samples of DCM LV and right ventricle (n = 18) were obtained fresh at heart transplant surgery. Parallel samples from nonfailing (NF) controls (n = 12) were from donor hearts found unsuitable for clinical use. We analyzed abundance of mtDNA and nuclear DNA (nDNA) using qPCR. LV mtDNA was depleted in DCM (50%, P < 0.05 each) compared with NF. No detectable change in RV mtDNA abundance occurred. DNA methylation and gene expression were determined using microarray analysis (GEO accession number: GSE43435). Fifty-seven gene promoters exhibited DNA hypermethylation or hypomethylation in DCM LVs. Among those, cytosolic thymidine kinase 1 (TK1) was hypermethylated. Expression arrays revealed decreased abundance of the TK1 mRNA transcript with no change in transcripts for other relevant thymidine metabolism enzymes. Quantitative immunoblots confirmed decreased TK1 polypeptide steady state abundance. TK1 activity remained unchanged in DCM samples while mitochondrial thymidine kinase (TK2) activity was significantly reduced. Compensatory TK activity was found in cardiac myocytes in the DCM LV. Diminished TK2 activity is mechanistically important to reduced mtDNA abundance and identified in DCM LV samples here. Epigenetic and genetic changes result in changes in mtDNA and in nucleotide substrates for mtDNA replication and underpin energy starvation in DCM.
Collapse
Affiliation(s)
- Christopher A Koczor
- Department of Pathology, Emory University School of Medicine, Atlanta, Georgia, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Liu S, Bai Y, Huang J, Zhao H, Zhang X, Hu S, Wei Y. Do mitochondria contribute to left ventricular non-compaction cardiomyopathy? New findings from myocardium of patients with left ventricular non-compaction cardiomyopathy. Mol Genet Metab 2013; 109:100-6. [PMID: 23465694 DOI: 10.1016/j.ymgme.2013.02.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 02/06/2013] [Indexed: 01/10/2023]
Abstract
BACKGROUND Left ventricular non-compaction cardiomyopathy (LVNC) is a rare congenital cardiomyopathy that is associated with mutations in mitochondrial DNA (mtDNA), however, no study of myocardium mtDNA of LVNC patients has been reported. To identify novel candidate mtDNA variants that may be responsible for the pathogenesis of LVNC, myocardial specimens were examined to investigate pathogenic mtDNA variants. MATERIALS AND METHODS Samples from six patients who were diagnosed with LVNC and underwent heart transplantation were analyzed. The sequence and copy number of mtDNA from these samples were determined by Sanger sequencing and fluorescence-based quantitative polymerase chain reaction, respectively. RESULTS Myocardial mtDNA sequences analysis revealed 227 substitution variants, including 157 coding variants and 70 non-coding variants. An m.9856T>C (Ile217Thr) mutation in MT-CO3 from one LVNC patient was found to be a non-haplogroup associated variant, and was rare in the mtDB Human Mitochondrial Genome Database, suggesting that the variant may be pathogenic. And there was statistically significant difference in mtDNA copy number between LVNC patients and normal control subjects. Electron microscopy (EM) of left ventricular myocardium showed abnormality in mitochondrial morphology and disordered sarcomeric organization. CONCLUSION The identification of mtDNA sequence variants in myocardial specimens may be helpful for further investigation of the underlying pathogenic implications of myocardial mtDNA mutations in LVNC. However, measurement of mtDNA copy number showed that there was lower mtDNA content in myocardium of LVNC patients than in normal controls (P<0.01). Lower mtDNA copy number and morphological abnormalities of mitochondria suggested mitochondrial dysfunction that may be associated with etiology of LVNC.
Collapse
Affiliation(s)
- Shenghua Liu
- State Key Laboratory of Cardiovascular Disease, National Center for Cardiovascular Disease, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, People's Republic of China
| | | | | | | | | | | | | |
Collapse
|
48
|
The exonuclease activity of the yeast mitochondrial DNA polymerase γ suppresses mitochondrial DNA deletions between short direct repeats in Saccharomyces cerevisiae. Genetics 2013; 194:519-22. [PMID: 23589460 DOI: 10.1534/genetics.113.150920] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The importance of mitochondrial DNA (mtDNA) deletions in the progeroid phenotype of exonuclease-deficient DNA polymerase γ mice has been intensely debated. We show that disruption of Mip1 exonuclease activity increases mtDNA deletions 160-fold, whereas disease-associated polymerase variants were mostly unaffected, suggesting that exonuclease activity is vital to avoid deletions during mtDNA replication.
Collapse
|
49
|
Stumpf JD, Saneto RP, Copeland WC. Clinical and molecular features of POLG-related mitochondrial disease. Cold Spring Harb Perspect Biol 2013; 5:a011395. [PMID: 23545419 DOI: 10.1101/cshperspect.a011395] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The inability to replicate mitochondrial genomes (mtDNA) by the mitochondrial DNA polymerase (pol γ) leads to a subset of mitochondrial diseases. Many mutations in POLG, the gene that encodes pol γ, have been associated with mitochondrial diseases such as myocerebrohepatopathy spectrum (MCHS) disorders, Alpers-Huttenlocher syndrome, myoclonic epilepsy myopathy sensory ataxia (MEMSA), ataxia neuropathy spectrum (ANS), and progressive external ophthalmoplegia (PEO). This chapter explores five important topics in POLG-related disease: (1) clinical symptoms that identify and distinguish POLG-related diseases, (2) molecular characterization of defects in polymerase activity by POLG disease variants, (3) the importance of holoenzyme formation in disease presentation, (4) the role of pol γ exonuclease activity and mutagenesis in disease and aging, and (5) novel approaches to therapy and avoidance of toxicity based on primary research in pol γ replication.
Collapse
Affiliation(s)
- Jeffrey D Stumpf
- Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | | | | |
Collapse
|
50
|
Rahn JJ, Stackley KD, Chan SSL. Opa1 is required for proper mitochondrial metabolism in early development. PLoS One 2013; 8:e59218. [PMID: 23516612 PMCID: PMC3597633 DOI: 10.1371/journal.pone.0059218] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 02/12/2013] [Indexed: 12/03/2022] Open
Abstract
Opa1 catalyzes fusion of inner mitochondrial membranes and formation of the cristae. OPA1 mutations in humans lead to autosomal dominant optic atrophy. OPA1 knockout mice lose viability around embryonic day 9 from unknown reasons, indicating that OPA1 is essential for embryonic development. Zebrafish are an attractive model for studying vertebrate development and have been used for many years to describe developmental events that are difficult or impractical to view in mammalian models. In this study, Opa1 was successfully depleted in zebrafish embryos using antisense morpholinos, which resulted in disrupted mitochondrial morphology. Phenotypically, these embryos exhibited abnormal blood circulation and heart defects, as well as small eyes and small pectoral fin buds. Additionally, startle response was reduced and locomotor activity was impaired. Furthermore, Opa1 depletion caused bioenergetic defects, without impairing mitochondrial efficiency. In response to mitochondrial dysfunction, a transient upregulation of the master regulator of mitochondrial biogenesis, pgc1a, was observed. These results not only reveal a new Opa1-associated phenotype in a vertebrate model system, but also further elucidates the absolute requirement of Opa1 for successful vertebrate development.
Collapse
Affiliation(s)
- Jennifer J Rahn
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | | | | |
Collapse
|