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Conti F, Di Martino S, Drago F, Bucolo C, Micale V, Montano V, Siciliano G, Mancuso M, Lopriore P. Red Flags in Primary Mitochondrial Diseases: What Should We Recognize? Int J Mol Sci 2023; 24:16746. [PMID: 38069070 PMCID: PMC10706469 DOI: 10.3390/ijms242316746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 11/22/2023] [Accepted: 11/23/2023] [Indexed: 12/18/2023] Open
Abstract
Primary mitochondrial diseases (PMDs) are complex group of metabolic disorders caused by genetically determined impairment of the mitochondrial oxidative phosphorylation (OXPHOS). The unique features of mitochondrial genetics and the pivotal role of mitochondria in cell biology explain the phenotypical heterogeneity of primary mitochondrial diseases and the resulting diagnostic challenges that follow. Some peculiar features ("red flags") may indicate a primary mitochondrial disease, helping the physician to orient in this diagnostic maze. In this narrative review, we aimed to outline the features of the most common mitochondrial red flags offering a general overview on the topic that could help physicians to untangle mitochondrial medicine complexity.
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Affiliation(s)
- Federica Conti
- Department of Biomedical and Biotechnological Science, School of Medicine, University of Catania, 95123 Catania, Italy; (F.C.); (S.D.M.); (C.B.); (V.M.)
| | - Serena Di Martino
- Department of Biomedical and Biotechnological Science, School of Medicine, University of Catania, 95123 Catania, Italy; (F.C.); (S.D.M.); (C.B.); (V.M.)
| | - Filippo Drago
- Department of Biomedical and Biotechnological Science, School of Medicine, University of Catania, 95123 Catania, Italy; (F.C.); (S.D.M.); (C.B.); (V.M.)
| | - Claudio Bucolo
- Department of Biomedical and Biotechnological Science, School of Medicine, University of Catania, 95123 Catania, Italy; (F.C.); (S.D.M.); (C.B.); (V.M.)
- Center for Research in Ocular Pharmacology-CERFO, University of Catania, 95213 Catania, Italy
| | - Vincenzo Micale
- Department of Biomedical and Biotechnological Science, School of Medicine, University of Catania, 95123 Catania, Italy; (F.C.); (S.D.M.); (C.B.); (V.M.)
| | - Vincenzo Montano
- Neurological Institute, Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy (P.L.)
| | - Gabriele Siciliano
- Neurological Institute, Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy (P.L.)
| | - Michelangelo Mancuso
- Neurological Institute, Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy (P.L.)
| | - Piervito Lopriore
- Neurological Institute, Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy (P.L.)
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Corrà S, Checchetto V, Brischigliaro M, Rampazzo C, Bottani E, Gagliani C, Cortese K, De Pittà C, Roverso M, De Stefani D, Bogialli S, Zeviani M, Viscomi C, Szabò I, Costa R. Drosophila Mpv17 forms an ion channel and regulates energy metabolism. iScience 2023; 26:107955. [PMID: 37810222 PMCID: PMC10558772 DOI: 10.1016/j.isci.2023.107955] [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: 12/26/2022] [Revised: 07/15/2023] [Accepted: 09/14/2023] [Indexed: 10/10/2023] Open
Abstract
Mutations in MPV17 are a major contributor to mitochondrial DNA (mtDNA) depletion syndromes, a group of inherited genetic conditions due to mtDNA instability. To investigate the role of MPV17 in mtDNA maintenance, we generated and characterized a Drosophila melanogaster Mpv17 (dMpv17) KO model showing that the absence of dMpv17 caused profound mtDNA depletion in the fat body but not in other tissues, increased glycolytic flux and reduced lifespan in starvation. Accordingly, the expression of key genes of glycogenolysis and glycolysis was upregulated in dMpv17 KO flies. In addition, we demonstrated that dMpv17 formed a channel in planar lipid bilayers at physiological ionic conditions, and its electrophysiological hallmarks were affected by pathological mutations. Importantly, the reconstituted channel translocated uridine but not orotate across the membrane. Our results indicate that dMpv17 forms a channel involved in translocation of key metabolites and highlight the importance of dMpv17 in energy homeostasis and mitochondrial function.
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Affiliation(s)
- Samantha Corrà
- Veneto Institute of Molecular Medicine (VIMM), Padova, Italy
| | | | | | | | - Emanuela Bottani
- Department of Diagnostic and Public Health, University of Verona, Verona, Italy
| | - Cristina Gagliani
- Department of Experimental Medicine, University of Genova, Genova, Italy
| | - Katia Cortese
- Department of Experimental Medicine, University of Genova, Genova, Italy
| | | | - Marco Roverso
- Department of Chemical Sciences, University of Padova, Padova, Italy
| | - Diego De Stefani
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Sara Bogialli
- Department of Chemical Sciences, University of Padova, Padova, Italy
| | - Massimo Zeviani
- Department of Neurosciences, University of Padova, Padova, Italy
- IRCCS Materno Infantile Burlo Garofolo, Trieste, Italy
| | - Carlo Viscomi
- Veneto Institute of Molecular Medicine (VIMM), Padova, Italy
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Ildiko Szabò
- Department of Biology, University of Padova, Padova, Italy
| | - Rodolfo Costa
- Department of Biology, University of Padova, Padova, Italy
- Institute of Neuroscience, National Research Council of Italy (CNR), Padova, Italy
- Chronobiology Section, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
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3
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Kristiansen CK, Furriol J, Chen A, Sullivan GJ, Bindoff LA, Liang KX. Deoxyribonucleoside treatment rescues EtBr-induced mtDNA depletion in iPSC-derived neural stem cells with POLG mutations. FASEB J 2023; 37:e23139. [PMID: 37584631 DOI: 10.1096/fj.202300650rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 07/26/2023] [Accepted: 07/31/2023] [Indexed: 08/17/2023]
Abstract
Mutations in POLG, the gene encoding the catalytic subunit of the mitochondrial DNA (mtDNA) polymerase gamma (Pol-γ), lead to diseases driven by defective mtDNA maintenance. Despite being the most prevalent cause of mitochondrial disease, treatments for POLG-related disorders remain elusive. In this study, we used POLG patient-induced pluripotent stem cell (iPSC)-derived neural stem cells (iNSCs), one homozygous for the POLG mutation c.2243G>C and one compound heterozygous with c.2243G>C and c.1399G>A, and treated these iNSCs with ethidium bromide (EtBr) to study the rate of depletion and repopulation of mtDNA. In addition, we investigated the effect of deoxyribonucleoside (dNs) supplementation on mtDNA maintenance during EtBr treatment and post-treatment repopulation in the same cells. EtBr-induced mtDNA depletion occurred at a similar rate in both patient and control iNSCs, however, restoration of mtDNA levels was significantly delayed in iNSCs carrying the compound heterozygous POLG mutations. In contrast, iNSC with the homozygous POLG mutation recovered their mtDNA at a rate similar to controls. When we treated cells with dNs, we found that this reduced EtBr-induced mtDNA depletion and significantly increased repopulation rates in both patient iNSCs. These observations are consistent with the hypothesis that mutations in POLG impair mtDNA repopulation also within intact neural lineage cells and suggest that those with compound heterozygous mutation have a more severe defect of mtDNA synthesis. Our findings further highlight the potential for dNs to improve mtDNA replication in the presence of POLG mutations, suggesting that this may offer a new therapeutic modality for mitochondrial diseases caused by disturbed mtDNA homeostasis.
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Affiliation(s)
- Cecilie Katrin Kristiansen
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Neuro-SysMed, Center of Excellence for Clinical Research in Neurological Diseases, Haukeland University Hospital, Bergen, Norway
| | - Jessica Furriol
- Department of Medicine, Haukeland University Hospital, Bergen, Norway
| | - Anbin Chen
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Department of Neurosurgery, Xinhua Hospital Affiliated with Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Gareth John Sullivan
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
- Institute of Immunology, Oslo University Hospital, Oslo, Norway
- Department of Pediatric Research, Oslo University Hospital, Oslo, Norway
| | - Laurence A Bindoff
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Department of Neurology, Haukeland University Hospital, Bergen, Norway
- National Advisory Unit for Congenital Metabolic Diseases, Oslo University Hospital, Oslo, Norway
| | - Kristina Xiao Liang
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Neuro-SysMed, Center of Excellence for Clinical Research in Neurological Diseases, Haukeland University Hospital, Bergen, Norway
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Magistrati M, Gilea AI, Gerra MC, Baruffini E, Dallabona C. Drug Drop Test: How to Quickly Identify Potential Therapeutic Compounds for Mitochondrial Diseases Using Yeast Saccharomyces cerevisiae. Int J Mol Sci 2023; 24:10696. [PMID: 37445873 DOI: 10.3390/ijms241310696] [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: 05/30/2023] [Revised: 06/22/2023] [Accepted: 06/25/2023] [Indexed: 07/15/2023] Open
Abstract
Mitochondrial diseases (MDs) refer to a group of clinically and genetically heterogeneous pathologies characterized by defective mitochondrial function and energy production. Unfortunately, there is no effective treatment for most MDs, and current therapeutic management is limited to relieving symptoms. The yeast Saccharomyces cerevisiae has been efficiently used as a model organism to study mitochondria-related disorders thanks to its easy manipulation and well-known mitochondrial biogenesis and metabolism. It has been successfully exploited both to validate alleged pathogenic variants identified in patients and to discover potential beneficial molecules for their treatment. The so-called "drug drop test", a phenotype-based high-throughput screening, especially if coupled with a drug repurposing approach, allows the identification of molecules with high translational potential in a cost-effective and time-saving manner. In addition to drug identification, S. cerevisiae can be used to point out the drug's target or pathway. To date, drug drop tests have been successfully carried out for a variety of disease models, leading to very promising results. The most relevant aspect is that studies on more complex model organisms confirmed the effectiveness of the drugs, strengthening the results obtained in yeast and demonstrating the usefulness of this screening as a novel approach to revealing new therapeutic molecules for MDs.
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Affiliation(s)
- Martina Magistrati
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Alexandru Ionut Gilea
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Maria Carla Gerra
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Enrico Baruffini
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Cristina Dallabona
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
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Feng Y, Imam Aliagan A, Tombo N, Bopassa JC. Mitofilin Heterozygote Mice Display an Increase in Myocardial Injury and Inflammation after Ischemia/Reperfusion. Antioxidants (Basel) 2023; 12:921. [PMID: 37107296 PMCID: PMC10135852 DOI: 10.3390/antiox12040921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 03/17/2023] [Accepted: 04/08/2023] [Indexed: 04/29/2023] Open
Abstract
Mitochondrial inner membrane protein (Mitofilin/Mic60) is part of a big complex that constituent the mitochondrial inner membrane organizing system (MINOS), which plays a critical role in maintaining mitochondrial architecture and function. We recently showed that Mitofilin physically binds to Cyclophilin D, and disruption of this interaction promotes the opening of mitochondrial permeability transition pore (mPTP) and determines the extent of I/R injury. Here, we investigated whether Mitofilin knockout in the mouse enhances myocardial injury and inflammation after I/R injury. We found that full-body deletion (homozygote) of Mitofilin induces a lethal effect in the offspring and that a single allele expression of Mitofilin is sufficient to rescue the mouse phenotype in normal conditions. Using non-ischemic hearts from wild-type (WT) and Mitofilin+/- (HET) mice, we report that the mitochondria structure and calcium retention capacity (CRC) required to induce the opening of mPTP were similar in both groups. However, the levels of mitochondrial dynamics proteins involved in both fusion/fission, including MFN2, DRP1, and OPA1, were slightly reduced in Mitofilin+/- mice compared to WT. After I/R, the CRC and cardiac functional recovery were reduced while the mitochondria structure was more damaged, and myocardial infarct size was increased in Mitofilin+/- mice compared to WT. Mitofilin+/- mice exhibited an increase in the mtDNA release in the cytosol and ROS production, as well as dysregulated SLC25As (3, 5, 11, and 22) solute carrier function, compared to WT. In addition, Mitofilin+/- mice displayed an increase in the transcript of pro-inflammatory markers, including IL-6, ICAM, and TNF-α. These results suggest that Mitofilin knockdown induces mitochondrial cristae damage that promotes dysregulation of SLC25As solute carriers, leading to an increase in ROS production and reduction in CRC after I/R. These effects are associated with an increase in the mtDNA release into the cytosol, where it activates signaling cascades leading to nuclear transcription of pro-inflammatory cytokines that aggravate I/R injury.
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Affiliation(s)
| | | | | | - Jean C. Bopassa
- Department of Cellular and Integrative Physiology, School of Medicine, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr., San Antonio, TX 78229, USA
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Lagies S, Pan D, Mohl DA, Plattner DA, Gentle IE, Kammerer B. Mitochondrial Metabolomics of Sym1-Depleted Yeast Cells Revealed Them to Be Lysine Auxotroph. Cells 2023; 12:692. [PMID: 36899826 PMCID: PMC10000845 DOI: 10.3390/cells12050692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/10/2023] [Accepted: 02/17/2023] [Indexed: 02/24/2023] Open
Abstract
Metabolomics has expanded from cellular to subcellular level to elucidate subcellular compartmentalization. By applying isolated mitochondria to metabolome analysis, the hallmark of mitochondrial metabolites has been unraveled, showing compartment-specific distribution and regulation of metabolites. This method was employed in this work to study a mitochondrial inner membrane protein Sym1, whose human ortholog MPV17 is related to mitochondria DNA depletion syndrome. Gas chromatography-mass spectrometry-based metabolic profiling was combined with targeted liquid chromatography-mass spectrometry analysis to cover more metabolites. Furthermore, we applied a workflow employing ultra-high performance liquid chromatography-quadrupole time of flight mass spectrometry with a powerful chemometrics platform, focusing on only significantly changed metabolites. This workflow highly reduced the complexity of acquired data without losing metabolites of interest. Consequently, forty-one novel metabolites were identified in addition to the combined method, of which two metabolites, 4-guanidinobutanal and 4-guanidinobutanoate, were identified for the first time in Saccharomyces cerevisiae. With compartment-specific metabolomics, we identified sym1Δ cells as lysine auxotroph. The highly reduced carbamoyl-aspartate and orotic acid indicate a potential role of the mitochondrial inner membrane protein Sym1 in pyrimidine metabolism.
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Affiliation(s)
- Simon Lagies
- Core Competence Metabolomics, Hilde-Mangold-Haus, University of Freiburg, 79104 Freiburg, Germany
- Institute of Organic Chemistry, University of Freiburg, 79104 Freiburg, Germany
| | - Daqiang Pan
- Core Competence Metabolomics, Hilde-Mangold-Haus, University of Freiburg, 79104 Freiburg, Germany
- Institute of Pharmaceutical Science, University of Freiburg, 79104 Freiburg, Germany
| | - Daniel A. Mohl
- Core Competence Metabolomics, Hilde-Mangold-Haus, University of Freiburg, 79104 Freiburg, Germany
- Institute of Organic Chemistry, University of Freiburg, 79104 Freiburg, Germany
| | - Dietmar A. Plattner
- Institute of Organic Chemistry, University of Freiburg, 79104 Freiburg, Germany
| | - Ian E. Gentle
- Institute of Medical Microbiology and Hygiene, Medical Center–University of Freiburg, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Bernd Kammerer
- Core Competence Metabolomics, Hilde-Mangold-Haus, University of Freiburg, 79104 Freiburg, Germany
- Institute of Organic Chemistry, University of Freiburg, 79104 Freiburg, Germany
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, 79104 Freiburg, Germany
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7
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A Drosophila model of the neurological symptoms in Mpv17-related diseases. Sci Rep 2022; 12:22632. [PMID: 36587049 PMCID: PMC9805426 DOI: 10.1038/s41598-022-27329-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 12/30/2022] [Indexed: 01/01/2023] Open
Abstract
Mutations in the Mpv17 gene are responsible for MPV17-related hepatocerebral mitochondrial DNA depletion syndrome and Charcot-Marie-Tooth (CMT) disease. Although several models including mouse, zebrafish, and cultured human cells, have been developed, the models do not show any neurological defects, which are often observed in patients. Therefore, we knocked down CG11077 (Drosophila Mpv17; dMpv17), an ortholog of human MPV17, in the nervous system in Drosophila melanogaster and investigated the behavioral and cellular phenotypes. The resulting dMpv17 knockdown larvae showed impaired locomotor activity and learning ability consistent with mitochondrial defects suggested by the reductions in mitochondrial DNA and ATP production and the increases in the levels of lactate and reactive oxygen species. Furthermore, an abnormal morphology of the neuromuscular junction, at the presynaptic terminal, was observed in dMpv17 knockdown larvae. These results reproduce well the symptoms of human diseases and partially reproduce the phenotypes of Mpv17-deficient model organisms. Therefore, we suggest that neuron-specific dMpv17 knockdown in Drosophila is a useful model for investigation of MPV17-related hepatocerebral mitochondrial DNA depletion syndrome and CMT caused by Mpv17 dysfunction.
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Almannai M, El-Hattab AW, Azamian MS, Ali M, Scaglia F. Mitochondrial DNA maintenance defects: potential therapeutic strategies. Mol Genet Metab 2022; 137:40-48. [PMID: 35914366 PMCID: PMC10401187 DOI: 10.1016/j.ymgme.2022.07.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 07/03/2022] [Accepted: 07/03/2022] [Indexed: 10/17/2022]
Abstract
Mitochondrial DNA (mtDNA) replication depends on the mitochondrial import of hundreds of nuclear encoded proteins that control the mitochondrial genome maintenance and integrity. Defects in these processes result in an expanding group of disorders called mtDNA maintenance defects that are characterized by mtDNA depletion and/or multiple mtDNA deletions with variable phenotypic manifestations. As it applies for mitochondrial disorders in general, current treatment options for mtDNA maintenance defects are limited. Lately, with the development of model organisms, improved understanding of the pathophysiology of these disorders, and a better knowledge of their natural history, the number of preclinical studies and existing and planned clinical trials has been increasing. In this review, we discuss recent preclinical studies and current and future clinical trials concerning potential therapeutic options for the different mtDNA maintenance defects.
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Affiliation(s)
- Mohammed Almannai
- Genetics and Precision Medicine Department (GPM), King Abdullah Specialized Children's Hospital (KASCH), King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia
| | - Ayman W El-Hattab
- Department of Clinical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Mahshid S Azamian
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - May Ali
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Fernando Scaglia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Texas Children's Hospital, Houston, TX, USA; Joint BCM-CUHK Center of Medical Genetics, Prince of Wales Hospital, Shatin, Hong Kong.
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Comprehensive Analysis on the Specific Role and Function of Mitochondrial Inner Membrane Protein MPV17 in Liver Hepatocellular Carcinoma. Genet Res (Camb) 2022; 2022:7236823. [PMID: 35919033 PMCID: PMC9325347 DOI: 10.1155/2022/7236823] [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: 04/28/2022] [Accepted: 06/06/2022] [Indexed: 11/25/2022] Open
Abstract
Background Liver hepatocellular carcinoma (LIHC) is the predominant type of liver cancer, and its treatment still faces great challenges presently. Mitochondrial inner membrane protein MPV17 is reported to be involved in multiple biological activities of cancers. Here, we seek to investigate the specific role and functions of MPV17 in LIHC progression. Methods Firstly, MPV17 expressions in various tumors and corresponding normal samples and LIHC groups with various clinical features were analyzed, respectively. Next, the relationship between MPV17 expression and LIHC survival was analyzed and verified by AUC curves. Besides, differentially expressed genes (DEGs) for LIHC were screened from TCGA and then analyzed by GO and KEGG. Then, MPV17 was analyzed by prognostic model, Cox analysis, predictive nomogram, pathway correlation, and immunoassay. Finally, the functions of MPV17 were determined by CCK-8 and Tranwell assays. Results In most tumors, MPV17 expression was higher than that in the normal group, and it was related to LIHC clinical features. In the LIHC survival analysis, highly expressed MPV17 was associated with a poor prognosis. Besides, 314 upregulated and 193 downregulated DEGs are mainly involved in the TNF signaling pathway and tyrosine metabolism. Through prognostic model, Cox analysis, and predictive nomogram, MPV17 had the prognostic value for LIHC. Gene-pathway correlation analysis showed that MPV17 had the strongest correlation with the G2M_checkpoint pathway. In an immunoassay, MPV17 had a strong correlation with many immune cells. Functional assays showed that MPV17 reduction in LIHC cells could inhibit cell invasion, migration, and proliferation. Conclusion MPV17, as a tumor promoter, could be a new biomarker for LIHC diagnosis and prognosis and probably shed new light on the exploration of LIHC therapies.
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Almannai M, Salah A, El-Hattab AW. Mitochondrial Membranes and Mitochondrial Genome: Interactions and Clinical Syndromes. MEMBRANES 2022; 12:membranes12060625. [PMID: 35736332 PMCID: PMC9229594 DOI: 10.3390/membranes12060625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 06/06/2022] [Accepted: 06/14/2022] [Indexed: 11/16/2022]
Abstract
Mitochondria are surrounded by two membranes; the outer mitochondrial membrane and the inner mitochondrial membrane. They are unique organelles since they have their own DNA, the mitochondrial DNA (mtDNA), which is replicated continuously. Mitochondrial membranes have direct interaction with mtDNA and are therefore involved in organization of the mitochondrial genome. They also play essential roles in mitochondrial dynamics and the supply of nucleotides for mtDNA synthesis. In this review, we will discuss how the mitochondrial membranes interact with mtDNA and how this interaction is essential for mtDNA maintenance. We will review different mtDNA maintenance disorders that result from defects in this crucial interaction. Finally, we will review therapeutic approaches relevant to defects in mitochondrial membranes.
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Affiliation(s)
- Mohammed Almannai
- Genetics and Precision Medicine Department, King Abdullah Specialized Children Hospital, Riyadh P.O. Box 22490, Saudi Arabia
- Correspondence:
| | - Azza Salah
- Department of Pediatrics, University Hospital Sharjah, Sharjah P.O. Box 72772, United Arab Emirates;
| | - Ayman W. El-Hattab
- Department of Pediatrics, University Hospital Sharjah, Sharjah P.O. Box 72772, United Arab Emirates;
- Department of Clinical Sciences, College of Medicine, University of Sharjah, Sharjah P.O. Box 27272, United Arab Emirates;
- Genetics and Metabolic Department, KidsHeart Medical Center, Abu Dhabi P.O. Box 505193, United Arab Emirates
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11
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Hanaford AR, Cho YJ, Nakai H. AAV-vector based gene therapy for mitochondrial disease: progress and future perspectives. Orphanet J Rare Dis 2022; 17:217. [PMID: 35668433 PMCID: PMC9169410 DOI: 10.1186/s13023-022-02324-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 04/09/2022] [Indexed: 12/11/2022] Open
Abstract
Mitochondrial diseases are a group of rare, heterogeneous diseases caused by gene mutations in both nuclear and mitochondrial genomes that result in defects in mitochondrial function. They are responsible for significant morbidity and mortality as they affect multiple organ systems and particularly those with high energy-utilizing tissues, such as the nervous system, skeletal muscle, and cardiac muscle. Virtually no effective treatments exist for these patients, despite the urgent need. As the majority of these conditions are monogenic and caused by mutations in nuclear genes, gene replacement is a highly attractive therapeutic strategy. Adeno-associated virus (AAV) is a well-characterized gene replacement vector, and its safety profile and ability to transduce quiescent cells nominates it as a potential gene therapy vehicle for several mitochondrial diseases. Indeed, AAV vector-based gene replacement is currently being explored in clinical trials for one mitochondrial disease (Leber hereditary optic neuropathy) and preclinical studies have been published investigating this strategy in other mitochondrial diseases. This review summarizes the preclinical findings of AAV vector-based gene replacement therapy for mitochondrial diseases including Leigh syndrome, Barth syndrome, ethylmalonic encephalopathy, and others.
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Affiliation(s)
- Allison R Hanaford
- Center for Integrative Brain Research, Seattle Children's Reserach Institute, Seattle, WA, 98101, USA.
- Papé Family Pediatric Research Institute, Oregon Health and Science University, Portland, OR, 97239, USA.
| | - Yoon-Jae Cho
- Papé Family Pediatric Research Institute, Oregon Health and Science University, Portland, OR, 97239, USA
- Division of Pediatric Neurology, Doernbecher Children's Hospital, Oregon Health and Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, 97239, USA
- Knight Cancer Institute, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Hiroyuki Nakai
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, 97239, USA
- Department of Molecular Immunology and Microbiology, Oregon Health and Science University, Portland, OR, 97239, USA
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, 97006, USA
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12
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Roy A, Kandettu A, Ray S, Chakrabarty S. Mitochondrial DNA replication and repair defects: Clinical phenotypes and therapeutic interventions. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148554. [PMID: 35341749 DOI: 10.1016/j.bbabio.2022.148554] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 03/06/2022] [Accepted: 03/16/2022] [Indexed: 12/15/2022]
Abstract
Mitochondria is a unique cellular organelle involved in multiple cellular processes and is critical for maintaining cellular homeostasis. This semi-autonomous organelle contains its circular genome - mtDNA (mitochondrial DNA), that undergoes continuous cycles of replication and repair to maintain the mitochondrial genome integrity. The majority of the mitochondrial genes, including mitochondrial replisome and repair genes, are nuclear-encoded. Although the repair machinery of mitochondria is quite efficient, the mitochondrial genome is highly susceptible to oxidative damage and other types of exogenous and endogenous agent-induced DNA damage, due to the absence of protective histones and their proximity to the main ROS production sites. Mutations in replication and repair genes of mitochondria can result in mtDNA depletion and deletions subsequently leading to mitochondrial genome instability. The combined action of mutations and deletions can result in compromised mitochondrial genome maintenance and lead to various mitochondrial disorders. Here, we review the mechanism of mitochondrial DNA replication and repair process, key proteins involved, and their altered function in mitochondrial disorders. The focus of this review will be on the key genes of mitochondrial DNA replication and repair machinery and the clinical phenotypes associated with mutations in these genes.
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Affiliation(s)
- Abhipsa Roy
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Amoolya Kandettu
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Swagat Ray
- Department of Life Sciences, School of Life and Environmental Sciences, University of Lincoln, Lincoln LN6 7TS, United Kingdom
| | - Sanjiban Chakrabarty
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India.
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232nd ENMC International Workshop: Recommendations for treatment of mitochondrial DNA maintenance disorders. 16 – 18 June 2017, Heemskerk, The Netherlands. Neuromuscul Disord 2022; 32:609-620. [DOI: 10.1016/j.nmd.2022.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 05/12/2022] [Indexed: 11/24/2022]
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14
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Abstract
Significance: The small, multicopy mitochondrial genome (mitochondrial DNA [mtDNA]) is essential for efficient energy production, as alterations in its coding information or a decrease in its copy number disrupt mitochondrial ATP synthesis. However, the mitochondrial replication machinery encounters numerous challenges that may limit its ability to duplicate this important genome and that jeopardize mtDNA stability, including various lesions in the DNA template, topological stress, and an insufficient nucleotide supply. Recent Advances: An ever-growing array of DNA repair or maintenance factors are being reported to localize to the mitochondria. We review current knowledge regarding the mitochondrial factors that may contribute to the tolerance or repair of various types of changes in the mitochondrial genome, such as base damage, incorporated ribonucleotides, and strand breaks. We also discuss the newly discovered link between mtDNA instability and activation of the innate immune response. Critical Issues: By which mechanisms do mitochondria respond to challenges that threaten mtDNA maintenance? What types of mtDNA damage are repaired, and when are the affected molecules degraded instead? And, finally, which forms of mtDNA instability trigger an immune response, and how? Future Directions: Further work is required to understand the contribution of the DNA repair and damage-tolerance factors present in the mitochondrial compartment, as well as the balance between mtDNA repair and degradation. Finally, efforts to understand the events underlying mtDNA release into the cytosol are warranted. Pursuing these and many related avenues can improve our understanding of what goes wrong in mitochondrial disease. Antioxid. Redox Signal. 36, 885-905.
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Affiliation(s)
- Gustavo Carvalho
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Bruno Marçal Repolês
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Isabela Mendes
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Paulina H Wanrooij
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
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15
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Shahroor MA, Lasorsa FM, Porcelli V, Dweikat I, Di Noia MA, Gur M, Agostino G, Shaag A, Rinaldi T, Gasparre G, Guerra F, Castegna A, Todisco S, Abu-Libdeh B, Elpeleg O, Palmieri L. PNC2 (SLC25A36) Deficiency Associated With the Hyperinsulinism/Hyperammonemia Syndrome. J Clin Endocrinol Metab 2022; 107:1346-1356. [PMID: 34971397 DOI: 10.1210/clinem/dgab932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Indexed: 11/19/2022]
Abstract
CONTEXT The hyperinsulinism/hyperammonemia (HI/HA) syndrome, the second-most common form of congenital hyperinsulinism, has been associated with dominant mutations in GLUD1, coding for the mitochondrial enzyme glutamate dehydrogenase, that increase enzyme activity by reducing its sensitivity to allosteric inhibition by GTP. OBJECTIVE To identify the underlying genetic etiology in 2 siblings who presented with the biochemical features of HI/HA syndrome but did not carry pathogenic variants in GLUD1, and to determine the functional impact of the newly identified mutation. METHODS The patients were investigated by whole exome sequencing. Yeast complementation studies and biochemical assays on the recombinant mutated protein were performed. The consequences of stable slc25a36 silencing in HeLa cells were also investigated. RESULTS A homozygous splice site variant was identified in solute carrier family 25, member 36 (SLC25A36), encoding the pyrimidine nucleotide carrier 2 (PNC2), a mitochondrial nucleotide carrier that transports pyrimidine as well as guanine nucleotides across the inner mitochondrial membrane. The mutation leads to a 26-aa in-frame deletion in the first repeat domain of the protein, which abolishes transport activity. Furthermore, knockdown of slc25a36 expression in HeLa cells caused a marked reduction in the mitochondrial GTP content, which likely leads to a hyperactivation of glutamate dehydrogenase in our patients. CONCLUSION We report for the first time a mutation in PNC2/SLC25A36 leading to HI/HA and provide functional evidence of the molecular mechanism responsible for this phenotype. Our findings underscore the importance of mitochondrial nucleotide metabolism and expand the role of mitochondrial transporters in insulin secretion.
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Affiliation(s)
- Maher A Shahroor
- Department of Pediatrics and Genetics, Al Makassed Hospital and Al-Quds University, 95908 Jerusalem, Palestine
- Department of Neonatology, Sunnybrook Health Sciences Center, University of Toronto, M4N 3M5 Toronto, Canada
| | - Francesco M Lasorsa
- Laboratory of Biochemistry and Molecular Biology, Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, 70125 Bari, Italy
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, 70125 Bari, Italy
| | - Vito Porcelli
- Laboratory of Biochemistry and Molecular Biology, Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Imad Dweikat
- Metabolic Unit, An-Najah National University, P467 Nablus, Palestine
| | - Maria Antonietta Di Noia
- Laboratory of Biochemistry and Molecular Biology, Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Michal Gur
- Department of Genetics, Hadassah, Hebrew University Medical Center, 91120 Jerusalem, Israel
| | - Giulia Agostino
- Laboratory of Biochemistry and Molecular Biology, Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Avraham Shaag
- Department of Genetics, Hadassah, Hebrew University Medical Center, 91120 Jerusalem, Israel
| | - Teresa Rinaldi
- Pasteur Institute-Cenci Bolognetti Foundation, Department of Biology and Biotechnology "Charles Darwin", University of Rome La Sapienza, 00185 Rome, Italy
| | - Giuseppe Gasparre
- Department of Medical and Surgical Sciences (DIMEC), Unit of Medical Genetics and Center for Applied Biomedical Research (CRBA), University of Bologna, 40138 Bologna, Italy
| | - Flora Guerra
- Department of Medical and Surgical Sciences (DIMEC), Unit of Medical Genetics and Center for Applied Biomedical Research (CRBA), University of Bologna, 40138 Bologna, Italy
| | - Alessandra Castegna
- Laboratory of Biochemistry and Molecular Biology, Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, 70125 Bari, Italy
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, 70125 Bari, Italy
| | - Simona Todisco
- Laboratory of Biochemistry and Molecular Biology, Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Bassam Abu-Libdeh
- Department of Pediatrics and Genetics, Al Makassed Hospital and Al-Quds University, 95908 Jerusalem, Palestine
| | - Orly Elpeleg
- Department of Genetics, Hadassah, Hebrew University Medical Center, 91120 Jerusalem, Israel
| | - Luigi Palmieri
- Laboratory of Biochemistry and Molecular Biology, Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, 70125 Bari, Italy
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, 70125 Bari, Italy
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16
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Pantic B, Ives D, Mennuni M, Perez-Rodriguez D, Fernandez-Pelayo U, Lopez de Arbina A, Muñoz-Oreja M, Villar-Fernandez M, Dang TMJ, Vergani L, Johnston IG, Pitceathly RDS, McFarland R, Hanna MG, Taylor RW, Holt IJ, Spinazzola A. 2-Deoxy-D-glucose couples mitochondrial DNA replication with mitochondrial fitness and promotes the selection of wild-type over mutant mitochondrial DNA. Nat Commun 2021; 12:6997. [PMID: 34873176 PMCID: PMC8648849 DOI: 10.1038/s41467-021-26829-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 10/18/2021] [Indexed: 11/21/2022] Open
Abstract
Pathological variants of human mitochondrial DNA (mtDNA) typically co-exist with wild-type molecules, but the factors driving the selection of each are not understood. Because mitochondrial fitness does not favour the propagation of functional mtDNAs in disease states, we sought to create conditions where it would be advantageous. Glucose and glutamine consumption are increased in mtDNA dysfunction, and so we targeted the use of both in cells carrying the pathogenic m.3243A>G variant with 2-Deoxy-D-glucose (2DG), or the related 5-thioglucose. Here, we show that both compounds selected wild-type over mutant mtDNA, restoring mtDNA expression and respiration. Mechanistically, 2DG selectively inhibits the replication of mutant mtDNA; and glutamine is the key target metabolite, as its withdrawal, too, suppresses mtDNA synthesis in mutant cells. Additionally, by restricting glucose utilization, 2DG supports functional mtDNAs, as glucose-fuelled respiration is critical for mtDNA replication in control cells, when glucose and glutamine are scarce. Hence, we demonstrate that mitochondrial fitness dictates metabolite preference for mtDNA replication; consequently, interventions that restrict metabolite availability can suppress pathological mtDNAs, by coupling mitochondrial fitness and replication. It has been a longstanding goal to promote the propagation of functional mitochondrial DNAs at the expense of pathological molecules in cells where the two species coexist. Here, the authors show that restricting the availability of glucose and glutamine can achieve this outcome.
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Affiliation(s)
- Boris Pantic
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Royal Free Campus, London, NW3 2PF, UK
| | - Daniel Ives
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Royal Free Campus, London, NW3 2PF, UK
| | - Mara Mennuni
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Royal Free Campus, London, NW3 2PF, UK
| | - Diego Perez-Rodriguez
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Royal Free Campus, London, NW3 2PF, UK
| | | | | | - Mikel Muñoz-Oreja
- Biodonostia Health Research Institute, 20014, San Sebastián, Spain.,Department of Pediatrics, Medicine and Nursing Faculty, Universidad de País Vasco, Bilbao, Spain
| | | | - Thanh-Mai Julie Dang
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Royal Free Campus, London, NW3 2PF, UK
| | - Lodovica Vergani
- Department of Neurosciences, University of Padova, 35128, Padova, Italy
| | - Iain G Johnston
- Faculty of Mathematics and Natural Sciences, University of Bergen, 5007, Bergen, Norway
| | - Robert D S Pitceathly
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, WC1N 3BG, UK
| | - Robert McFarland
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Michael G Hanna
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, WC1N 3BG, UK
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Ian J Holt
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Royal Free Campus, London, NW3 2PF, UK. .,Biodonostia Health Research Institute, 20014, San Sebastián, Spain. .,IKERBASQUE, Basque Foundation for Science, 48013, Bilbao, Spain. .,CIBERNED (Center for Networked Biomedical Research on Neurodegenerative Diseases, Ministry of Economy and Competitiveness, Institute Carlos III), 28031, Madrid, Spain. .,Universidad de País Vasco, Barrio Sarriena s/n, 48940, Leioa, Bilbao, Spain.
| | - Antonella Spinazzola
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Royal Free Campus, London, NW3 2PF, UK.
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17
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Saccharomyces cerevisiae as a Tool for Studying Mutations in Nuclear Genes Involved in Diseases Caused by Mitochondrial DNA Instability. Genes (Basel) 2021; 12:genes12121866. [PMID: 34946817 PMCID: PMC8701800 DOI: 10.3390/genes12121866] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/20/2021] [Accepted: 11/23/2021] [Indexed: 01/03/2023] Open
Abstract
Mitochondrial DNA (mtDNA) maintenance is critical for oxidative phosphorylation (OXPHOS) since some subunits of the respiratory chain complexes are mitochondrially encoded. Pathological mutations in nuclear genes involved in the mtDNA metabolism may result in a quantitative decrease in mtDNA levels, referred to as mtDNA depletion, or in qualitative defects in mtDNA, especially in multiple deletions. Since, in the last decade, most of the novel mutations have been identified through whole-exome sequencing, it is crucial to confirm the pathogenicity by functional analysis in the appropriate model systems. Among these, the yeast Saccharomyces cerevisiae has proved to be a good model for studying mutations associated with mtDNA instability. This review focuses on the use of yeast for evaluating the pathogenicity of mutations in six genes, MPV17/SYM1, MRM2/MRM2, OPA1/MGM1, POLG/MIP1, RRM2B/RNR2, and SLC25A4/AAC2, all associated with mtDNA depletion or multiple deletions. We highlight the techniques used to construct a specific model and to measure the mtDNA instability as well as the main results obtained. We then report the contribution that yeast has given in understanding the pathogenic mechanisms of the mutant variants, in finding the genetic suppressors of the mitochondrial defects and in the discovery of molecules able to improve the mtDNA stability.
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18
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di Punzio G, Gilberti M, Baruffini E, Lodi T, Donnini C, Dallabona C. A Yeast-Based Repurposing Approach for the Treatment of Mitochondrial DNA Depletion Syndromes Led to the Identification of Molecules Able to Modulate the dNTP Pool. Int J Mol Sci 2021; 22:ijms222212223. [PMID: 34830106 PMCID: PMC8621932 DOI: 10.3390/ijms222212223] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/08/2021] [Accepted: 11/09/2021] [Indexed: 12/30/2022] Open
Abstract
Mitochondrial DNA depletion syndromes (MDS) are clinically heterogenous and often severe diseases, characterized by a reduction of the number of copies of mitochondrial DNA (mtDNA) in affected tissues. In the context of MDS, yeast has proved to be both an excellent model for the study of the mechanisms underlying mitochondrial pathologies and for the discovery of new therapies via high-throughput assays. Among the several genes involved in MDS, it has been shown that recessive mutations in MPV17 cause a hepatocerebral form of MDS and Navajo neurohepatopathy. MPV17 encodes a non selective channel in the inner mitochondrial membrane, but its physiological role and the nature of its cargo remains elusive. In this study we identify ten drugs active against MPV17 disorder, modelled in yeast using the homologous gene SYM1. All ten of the identified molecules cause a concomitant increase of both the mitochondrial deoxyribonucleoside triphosphate (mtdNTP) pool and mtDNA stability, which suggests that the reduced availability of DNA synthesis precursors is the cause for the mtDNA deletion and depletion associated with Sym1 deficiency. We finally evaluated the effect of these molecules on mtDNA stability in two other MDS yeast models, extending the potential use of these drugs to a wider range of MDS patients.
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Landoni JC, Wang L, Suomalainen A. Whole-Cell and Mitochondrial dNTP Pool Quantification from Cells and Tissues. Methods Mol Biol 2021; 2276:143-151. [PMID: 34060038 DOI: 10.1007/978-1-0716-1266-8_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Deoxynucleoside 5'-triphosphates (dNTPs) are the molecular building blocks for DNA synthesis, and their balanced concentration in the cell is fundamental for health. dNTP imbalance can lead to genomic instability and other metabolic disturbances, resulting in devastating mitochondrial diseases.The accurate and efficient measurement of dNTPs from different biological samples and cellular compartments is vital to understand the mechanisms behind these diseases and develop and scrutinize their possible treatments. This chapter describes an update on the most recent development of the traditional radiolabeled polymerase extension method and its adaptation for the measurement of whole-cell and mitochondrial dNTP pools from cultured cells and tissue samples. The solid-phase reaction setting enables an increase in efficiency, accuracy, and measurement scale.
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Affiliation(s)
- Juan C Landoni
- Research Programs Unit, Stem Cells and Metabolism, University of Helsinki, Helsinki, Finland
| | - Liya Wang
- Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Anu Suomalainen
- University Hospital, Department of Neurology, Helsinki, Finland.
- Neuroscience Center, University of Helsinki, Helsinki, Finland.
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20
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Ramón J, Vila-Julià F, Molina-Granada D, Molina-Berenguer M, Melià MJ, García-Arumí E, Torres-Torronteras J, Cámara Y, Martí R. Therapy Prospects for Mitochondrial DNA Maintenance Disorders. Int J Mol Sci 2021; 22:6447. [PMID: 34208592 PMCID: PMC8234938 DOI: 10.3390/ijms22126447] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 06/10/2021] [Accepted: 06/11/2021] [Indexed: 02/07/2023] Open
Abstract
Mitochondrial DNA depletion and multiple deletions syndromes (MDDS) constitute a group of mitochondrial diseases defined by dysfunctional mitochondrial DNA (mtDNA) replication and maintenance. As is the case for many other mitochondrial diseases, the options for the treatment of these disorders are rather limited today. Some aggressive treatments such as liver transplantation or allogeneic stem cell transplantation are among the few available options for patients with some forms of MDDS. However, in recent years, significant advances in our knowledge of the biochemical pathomechanisms accounting for dysfunctional mtDNA replication have been achieved, which has opened new prospects for the treatment of these often fatal diseases. Current strategies under investigation to treat MDDS range from small molecule substrate enhancement approaches to more complex treatments, such as lentiviral or adenoassociated vector-mediated gene therapy. Some of these experimental therapies have already reached the clinical phase with very promising results, however, they are hampered by the fact that these are all rare disorders and so the patient recruitment potential for clinical trials is very limited.
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Affiliation(s)
- Javier Ramón
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Ferran Vila-Julià
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - David Molina-Granada
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Miguel Molina-Berenguer
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Maria Jesús Melià
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Elena García-Arumí
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Javier Torres-Torronteras
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Yolanda Cámara
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Ramon Martí
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
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21
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Sperl LE, Hagn F. NMR Structural and Biophysical Analysis of the Disease-Linked Inner Mitochondrial Membrane Protein MPV17. J Mol Biol 2021; 433:167098. [PMID: 34116124 DOI: 10.1016/j.jmb.2021.167098] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 05/19/2021] [Accepted: 06/03/2021] [Indexed: 11/30/2022]
Abstract
MPV17 is an integral inner mitochondrial membrane protein, whose loss-of-function is linked to the hepatocerebral form of the mitochondrial-DNA-depletion syndrome, leading to a tissue-specific reduction of mitochondrial DNA and organ failure in infants. Several disease-causing mutations in MPV17 have been identified and earlier studies with reconstituted protein suggest that MPV17 forms a high conductivity channel in the membrane. However, the molecular and structural basis of the MPV17 functionality remain only poorly understood. In order to make MPV17 accessible to high-resolution structural studies, we here present an efficient protocol for its high-level production in E. coli and refolding into detergent micelles. Using biophysical and NMR methods, we show that refolded MPV17 in detergent micelles adopts a compact structure consisting of six membrane-embedded α-helices. Furthermore, we demonstrate that MPV17 forms oligomers in a lipid bilayer that are further stabilized by disulfide-bridges. In line with these findings, MPV17 could only be inserted into lipid nanodiscs of 8-12 nm in diameter if intrinsic cysteines were either removed by mutagenesis or blocked by chemical modification. Using this nanodisc reconstitution approach, we could show that disease-linked mutations in MPV17 abolish its oligomerization properties in the membrane. These data suggest that, induced by oxidative stress, MPV17 can alter its oligomeric state from a properly folded monomer to a disulfide-stabilized oligomeric pore which might be required for the transport of metabolic DNA precursors into the mitochondrial matrix to compensate for the damage caused by reactive oxygen species.
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Affiliation(s)
- Laura E Sperl
- Structural Membrane Biochemistry, Bavarian NMR Center (BNMRZ) at the Department of Chemistry, Technical University of Munich, Ernst-Otto-Fischer-Str. 2, 85748 Garching, Germany
| | - Franz Hagn
- Structural Membrane Biochemistry, Bavarian NMR Center (BNMRZ) at the Department of Chemistry, Technical University of Munich, Ernst-Otto-Fischer-Str. 2, 85748 Garching, Germany; Institute of Structural Biology, Helmholtz Center Munich, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany.
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22
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Hong KT, Lim BC, Moon JS, Ko JS. MPV17-related Hepatocerebral Mitochondrial DNA Depletion Syndrome. THE KOREAN JOURNAL OF GASTROENTEROLOGY 2021; 77:248-252. [PMID: 34035203 DOI: 10.4166/kjg.2020.170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/09/2021] [Accepted: 02/11/2021] [Indexed: 11/03/2022]
Abstract
Mitochondrial DNA (mtDNA) depletion syndrome comprises diseases resulting from a deficiency of proteins involved in mtDNA synthesis. MPV17 is a mitochondrial membrane protein whose mutation causes mitochondrial deoxynucleotide insufficiency. MPV17-related hepatocerebral mtDNA depletion syndrome is a rare autosomal recessive disease. This case report describes the clinical manifestations of MPV17-related hepatocerebral mtDNA depletion syndrome analyzed by performing whole-exome sequencing (WES). A 17-month-old girl presented with developmental delay, jaundice, and failure to thrive. The laboratory findings revealed cholestatic hepatitis, increased lactate-to-pyruvate ratio, and prolongation of the prothrombin time. She developed a hypoglycemic seizure. Brain magnetic resonance imaging revealed extensive demyelination of the white matter. WES detected the p.Leu151fs and p.Pro98Leu variants in MPV17. Her parents and sibling were found to be MPV17 heterozygous carriers. She was administered supportive treatment, such as replacement of fat-soluble vitamins and cornstarch to prevent further hypoglycemic events. The patient is currently being considered for liver transplantation. Overall, WES can help diagnose hepatocerebral mtDNA depletion syndrome in patients with hepatopathy, developmental delay, lactic acidosis, and hypomyelination based on brain magnetic resonance imaging.
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Affiliation(s)
- Ki Teak Hong
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
| | - Byung Chan Lim
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
| | - Jin Soo Moon
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
| | - Jae Sung Ko
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
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23
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Jacinto S, Guerreiro P, de Oliveira RM, Cunha-Oliveira T, Santos MJ, Grazina M, Rego AC, Outeiro TF. MPV17 Mutations Are Associated With a Quiescent Energetic Metabolic Profile. Front Cell Neurosci 2021; 15:641264. [PMID: 33815063 PMCID: PMC8011494 DOI: 10.3389/fncel.2021.641264] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 02/08/2021] [Indexed: 02/03/2023] Open
Abstract
Mutations in the MPV17 gene are associated with hepatocerebral form of mitochondrial depletion syndrome. The mechanisms through which MPV17 mutations cause respiratory chain dysfunction and mtDNA depletion is still unclear. The MPV17 gene encodes an inner membrane mitochondrial protein that was recently described to function as a non-selective channel. Although its exact function is unknown, it is thought to be important in the maintenance of mitochondrial membrane potential (ΔΨm). To obtain more information about the role of MPV17 in human disease, we investigated the effect of MPV17 knockdown and of selected known MPV17 mutations associated with MPV17 disease in vitro. We used different approaches in order to evaluate the cellular consequences of MPV17 deficiency. We found that lower levels of MPV17 were associated with impaired mitochondrial respiration and with a quiescent energetic metabolic profile. All the mutations studied destabilized the protein, resulting in reduced protein levels. We also demonstrated that different mutations caused different cellular abnormalities, including increased ROS production, decreased oxygen consumption, loss of ΔΨm, and mislocalization of MPV17 protein. Our study provides novel insight into the molecular effects of MPV17 mutations and opens novel possibilities for testing therapeutic strategies for a devastating group of disorders.
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Affiliation(s)
- Sandra Jacinto
- Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Serviço de Neurologia Pediátrica, Hospital Dona Estefânia, Centro Hospitalar Universitário Lisboa Central-EPE, Lisboa, Portugal
| | - Patrícia Guerreiro
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany.,Switch Laboratory, Center for Brain and Disease Research, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium.,Switch Laboratory, Department of Cellular and Molecular Medicine, Katholiek Universiteit (KU), Leuven, Belgium
| | - Rita Machado de Oliveira
- CEDOC - Chronic Diseases Research Center, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
| | | | - Maria João Santos
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,CIBB - Center for Innovative Biomedicine and Biotechnology, University of Coimbra, Portugal
| | - Manuela Grazina
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,CIBB - Center for Innovative Biomedicine and Biotechnology, University of Coimbra, Portugal
| | - Ana Cristina Rego
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Tiago F Outeiro
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany.,Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom.,Max Planck Institute for Experimental Medicine, Göttingen, Germany
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24
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Müller‐Nedebock AC, Westhuizen FH, Kõks S, Bardien S. Nuclear Genes Associated with Mitochondrial
DNA
Processes as Contributors to Parkinson's Disease Risk. Mov Disord 2021; 36:815-831. [DOI: 10.1002/mds.28475] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 12/07/2020] [Accepted: 12/16/2020] [Indexed: 12/11/2022] Open
Affiliation(s)
- Amica C. Müller‐Nedebock
- Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences Stellenbosch University Cape Town South Africa
| | | | - Sulev Kõks
- Perron Institute for Neurological and Translational Science Nedlands Western Australia Australia
- Centre for Molecular Medicine and Innovative Therapeutics Murdoch University Murdoch Western Australia Australia
| | - Soraya Bardien
- Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences Stellenbosch University Cape Town South Africa
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25
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Luna-Sanchez M, Benincá C, Cerutti R, Brea-Calvo G, Yeates A, Scorrano L, Zeviani M, Viscomi C. Opa1 Overexpression Protects from Early-Onset Mpv17 -/--Related Mouse Kidney Disease. Mol Ther 2020; 28:1918-1930. [PMID: 32562616 PMCID: PMC7403474 DOI: 10.1016/j.ymthe.2020.06.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 05/06/2020] [Accepted: 06/08/2020] [Indexed: 12/29/2022] Open
Abstract
Moderate overexpression of Opa1, the master regulator of mitochondrial cristae morphology, significantly improved mitochondrial damage induced by drugs, surgical denervation, or oxidative phosphorylation (OXPHOS) defects due to specific impairment of a single mitochondrial respiratory chain complex. Here, we investigated the effectiveness of this approach in the Mpv17-/- mouse, characterized by profound, multisystem mitochondrial DNA (mtDNA) depletion. After the crossing with Opa1tg mice, we found a surprising anticipation of the severe, progressive focal segmental glomerulosclerosis, previously described in Mpv17-/- animals as a late-onset clinical feature (after 12-18 months of life). In contrast, Mpv17-/- animals from this new "mixed" strain died at 8-9 weeks after birth because of severe kidney failure However, Mpv17-/-::Opa1tg mice lived much longer than Mpv17-/- littermates and developed the kidney dysfunction much later. mtDNA content and OXPHOS activities were significantly higher in Mpv17-/-::Opa1tg than in Mpv17-/- kidneys and similar to those for wild-type (WT) littermates. Mitochondrial network and cristae ultrastructure were largely preserved in Mpv17-/-::Opa1tg versus Mpv17-/- kidney and isolated podocytes. Mechanistically, the protective effect of Opa1 overexpression in this model was mediated by a block in apoptosis due to the stabilization of the mitochondrial cristae. These results demonstrate that strategies aiming at increasing Opa1 expression or activity can be effective against mtDNA depletion syndromes.
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Affiliation(s)
- Marta Luna-Sanchez
- University of Cambridge - MRC Mitochondrial Biology Unit, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Cristiane Benincá
- University of Cambridge - MRC Mitochondrial Biology Unit, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Raffaele Cerutti
- University of Cambridge - MRC Mitochondrial Biology Unit, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Gloria Brea-Calvo
- Centro Andaluz de Biología de Desarrollo and CIBERER, ISCIII, Universidad Pablo de Olavide-CSIC-JA, 41013 Sevilla, Spain
| | - Anna Yeates
- Medical Research Council - Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Luca Scorrano
- Venetian Institute of Molecular Medicine, Via Orus 2, 35128 Padova, Italy; Department of Biology, University of Padova, via Ugo Bassi 58/B, 35131 Padova, Italy
| | - Massimo Zeviani
- Venetian Institute of Molecular Medicine, Via Orus 2, 35128 Padova, Italy; Department of Neurosciences, University of Padova, via Giustiniani 2, 35128 Padova, Italy.
| | - Carlo Viscomi
- Department of Biomedical Sciences, University of Padova, via Ugo Bassi 58/B, 35131 Padova, Italy.
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26
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Madungwe NB, Feng Y, Imam Aliagan A, Tombo N, Kaya F, Bopassa JC. Inner mitochondrial membrane protein MPV17 mutant mice display increased myocardial injury after ischemia/reperfusion. Am J Transl Res 2020; 12:3412-3428. [PMID: 32774709 PMCID: PMC7407695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 06/01/2020] [Indexed: 06/11/2023]
Abstract
MPV17 is an inner mitochondrial membrane protein whose mutation results in mitochondrial DNA (mtDNA) depletion diseases such as neurohepatopathy. MPV17 is expressed in several organs including the liver and kidneys. Here, we investigated its role and mechanism of action in cardiac ischemia/reperfusion (I/R) injury. Using isolated hearts from wild type and Mpv17 mutant (Mpv17mut) mice, we found that mtDNA levels and normal cardiac function were similar between the groups. Furthermore, reactive oxygen species (ROS) generation, mitochondrial morphology, and calcium levels required to trigger mitochondrial permeability transition pore (mPTP) opening were all similar in normal/non-ischemic animals. However, following I/R, we found that mutant mice had poorer cardiac functional recovery and exhibited more mitochondrial structural damage. We also found that after I/R, Mpv17mut heart mitochondria did not produce more ROS than wild type hearts but that calcium retention capacity was gravely compromised. Using immunoprecipitation and mass spectrometry, we identified ATP synthase, Cyclophilin D, MIC60 and GRP75 as proteins critical to mitochondrial cristae organization and calcium handling that interact with MPV17, and this interaction is reduced by I/R. Together our results suggest that MPV17 has a protective function in the heart and is necessary for recovery following insults to the heart.
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Affiliation(s)
- Ngonidzashe B Madungwe
- Department of Cellular and Integrative Physiology, School of Medicine, University of Texas Health Science Center at San AntonioTX 78229, USA
- Department of Biomedical Engineering, University of Texas at San AntonioTX 78249, USA
| | - Yansheng Feng
- Department of Cellular and Integrative Physiology, School of Medicine, University of Texas Health Science Center at San AntonioTX 78229, USA
| | - Abdulhafiz Imam Aliagan
- Department of Cellular and Integrative Physiology, School of Medicine, University of Texas Health Science Center at San AntonioTX 78229, USA
| | - Nathalie Tombo
- Department of Cellular and Integrative Physiology, School of Medicine, University of Texas Health Science Center at San AntonioTX 78229, USA
| | - Ferdinand Kaya
- Department of Ophthalmology, University of California DavisCA 95616, USA
| | - Jean C Bopassa
- Department of Cellular and Integrative Physiology, School of Medicine, University of Texas Health Science Center at San AntonioTX 78229, USA
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27
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Wi J, Na Y, Yang E, Lee JH, Jeong WJ, Choi DW. Arabidopsis AtMPV17, a homolog of mice MPV17, enhances osmotic stress tolerance. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2020; 26:1341-1348. [PMID: 32647452 PMCID: PMC7326884 DOI: 10.1007/s12298-020-00834-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 04/28/2020] [Accepted: 06/07/2020] [Indexed: 06/11/2023]
Abstract
Mutation in the human MPV17 gene or the functional yeast orthologue SYM1 result in mitochondrial DNA depletion. MPV17 homologs are also found in plants including Arabidopsis, but the function of these genes remain unclear. Arabidopsis genome contains 10 MPV17 homologs. Among these, the AtMPV17 protein was localized in mitochondria as MPV17 and SYM1. The yeast sym1 knock out mutant cannot grow on ethanol-containing medium at 37 °C. AtMPV17 complements the ethanol growth defection of sym1 yeast MPV17 ortholog cells at 37 °C, suggesting that AtMPV17 is a functional ortholog of SYM1. AtMPV17 knock out mutant, atmpv17 show similar growth and seed development to those of the wild-type plant on normal growth condition. However, atmpv17 mutant is more sensitive to ABA and mannitol during germination and seedling growth than wild type plants. Growth retardation of the atmpv17 knock out mutant on medium containing ABA and mannitol is complemented by AtMPV17 overexpression. These results suggest that the AtMPV17 contributes to osmotic stress tolerance in plants.
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Affiliation(s)
- Jiwoong Wi
- Department of Biology Education, Chonnam National University, Gwangju, 61186 Republic of Korea
| | - Yeonju Na
- Department of Biology Education, Chonnam National University, Gwangju, 61186 Republic of Korea
| | - Eunju Yang
- Department of Biology Education, Chonnam National University, Gwangju, 61186 Republic of Korea
| | - Jung-Hyun Lee
- Department of Biology Education, Chonnam National University, Gwangju, 61186 Republic of Korea
| | - Won-Joong Jeong
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, 34141 Republic of Korea
| | - Dong-Woog Choi
- Department of Biology Education, Chonnam National University, Gwangju, 61186 Republic of Korea
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28
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Canonne M, Wanet A, Nguyen TTA, Khelfi A, Ayama-Canden S, Van Steenbrugge M, Fattaccioli A, Sokal E, Najimi M, Arnould T, Renard P. MPV17 does not control cancer cell proliferation. PLoS One 2020; 15:e0229834. [PMID: 32155188 PMCID: PMC7064194 DOI: 10.1371/journal.pone.0229834] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 02/14/2020] [Indexed: 11/19/2022] Open
Abstract
MPV17 is described as a mitochondrial inner membrane channel. Although its function remains elusive, mutations in the MPV17 gene result in hepato-cerebral mitochondrial DNA depletion syndrome in humans. In this study, we show that MPV17 silencing does not induce depletion in mitochondrial DNA content in cancer cells. We also show that MPV17 does not control cancer cell proliferation despite the fact that we initially observed a reduced proliferation rate in five MPV17-silenced cancer cell lines with two different shRNAs. However, shRNA-mediated MPV17 knockdown performed in this work provided misguiding results regarding the resulting proliferation phenotype and only a rescue experiment was able to shed definitive light on the implication of MPV17 in cancer cell proliferation. Our results therefore emphasize the caution that is required when scientific conclusions are drawn from a work based on lentiviral vector-based gene silencing and clearly demonstrate the need to systematically perform a rescue experiment in order to ascertain the specific nature of the experimental results.
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Affiliation(s)
- Morgane Canonne
- Laboratory of Biochemistry and Cell Biology (URBC), NAmur Research Institute for LIfe Sciences (NARILIS), University of Namur (UNamur), Namur, Belgium
| | - Anaïs Wanet
- Laboratory of Biochemistry and Cell Biology (URBC), NAmur Research Institute for LIfe Sciences (NARILIS), University of Namur (UNamur), Namur, Belgium
| | - Thuy Truong An Nguyen
- Laboratory of Biochemistry and Cell Biology (URBC), NAmur Research Institute for LIfe Sciences (NARILIS), University of Namur (UNamur), Namur, Belgium
| | - Alexis Khelfi
- Laboratory of Biochemistry and Cell Biology (URBC), NAmur Research Institute for LIfe Sciences (NARILIS), University of Namur (UNamur), Namur, Belgium
| | - Sophie Ayama-Canden
- Laboratory of Biochemistry and Cell Biology (URBC), NAmur Research Institute for LIfe Sciences (NARILIS), University of Namur (UNamur), Namur, Belgium
| | - Martine Van Steenbrugge
- Laboratory of Biochemistry and Cell Biology (URBC), NAmur Research Institute for LIfe Sciences (NARILIS), University of Namur (UNamur), Namur, Belgium
| | - Antoine Fattaccioli
- Laboratory of Biochemistry and Cell Biology (URBC), NAmur Research Institute for LIfe Sciences (NARILIS), University of Namur (UNamur), Namur, Belgium
| | - Etienne Sokal
- Laboratory of Pediatric Hepatology and Cell Therapy, Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain, Brussels, Belgium
| | - Mustapha Najimi
- Laboratory of Pediatric Hepatology and Cell Therapy, Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain, Brussels, Belgium
| | - Thierry Arnould
- Laboratory of Biochemistry and Cell Biology (URBC), NAmur Research Institute for LIfe Sciences (NARILIS), University of Namur (UNamur), Namur, Belgium
| | - Patricia Renard
- Laboratory of Biochemistry and Cell Biology (URBC), NAmur Research Institute for LIfe Sciences (NARILIS), University of Namur (UNamur), Namur, Belgium
- * E-mail:
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29
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Sommerville EW, Dalla Rosa I, Rosenberg MM, Bruni F, Thompson K, Rocha M, Blakely EL, He L, Falkous G, Schaefer AM, Yu‐Wai‐Man P, Chinnery PF, Hedstrom L, Spinazzola A, Taylor RW, Gorman GS. Identification of a novel heterozygous guanosine monophosphate reductase (GMPR) variant in a patient with a late-onset disorder of mitochondrial DNA maintenance. Clin Genet 2020; 97:276-286. [PMID: 31600844 PMCID: PMC7004030 DOI: 10.1111/cge.13652] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 09/18/2019] [Accepted: 09/27/2019] [Indexed: 12/18/2022]
Abstract
Autosomal dominant progressive external ophthalmoplegia (adPEO) is a late-onset, Mendelian mitochondrial disorder characterised by paresis of the extraocular muscles, ptosis, and skeletal-muscle restricted multiple mitochondrial DNA (mtDNA) deletions. Although dominantly inherited, pathogenic variants in POLG, TWNK and RRM2B are among the most common genetic defects of adPEO, identification of novel candidate genes and the underlying pathomechanisms remains challenging. We report the clinical, genetic and molecular investigations of a patient who presented in the seventh decade of life with PEO. Oxidative histochemistry revealed cytochrome c oxidase-deficient fibres and occasional ragged red fibres showing subsarcolemmal mitochondrial accumulation in skeletal muscle, while molecular studies identified the presence of multiple mtDNA deletions. Negative candidate screening of known nuclear genes associated with PEO prompted diagnostic exome sequencing, leading to the prioritisation of a novel heterozygous c.547G>C variant in GMPR (NM_006877.3) encoding guanosine monophosphate reductase, a cytosolic enzyme required for maintaining the cellular balance of adenine and guanine nucleotides. We show that the novel c.547G>C variant causes aberrant splicing, decreased GMPR protein levels in patient skeletal muscle, proliferating and quiescent cells, and is associated with subtle changes in nucleotide homeostasis protein levels and evidence of disturbed mtDNA maintenance in skeletal muscle. Despite confirmation of GMPR deficiency, demonstrating marked defects of mtDNA replication or nucleotide homeostasis in patient cells proved challenging. Our study proposes that GMPR is the 19th locus for PEO and highlights the complexities of uncovering disease mechanisms in late-onset PEO phenotypes.
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Affiliation(s)
- Ewen W. Sommerville
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Ilaria Dalla Rosa
- Department of Clinical and Movement Neurosciences, UCL Queens Square Institute of Neurology, Royal Free CampusUniversity College LondonLondonUK
| | | | - Francesco Bruni
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
- Department of Biosciences, Biotechnologies and BiopharmaceuticsUniversity of Bari “ldo Moro”BariItaly
| | - Kyle Thompson
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Mariana Rocha
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Emma L. Blakely
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Langping He
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Gavin Falkous
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Andrew M. Schaefer
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Patrick Yu‐Wai‐Man
- NIHR Biomedical Research Centre at Moorfields Eye Hospital and UCL Institute of OphthalmologyLondonUK
- MRC Mitochondrial Biology UnitUniversity of CambridgeCambridgeUK
- Cambridge Centre for Brain Repair, Department of Clinical NeurosciencesUniversity of CambridgeCambridgeUK
| | - Patrick F. Chinnery
- Department of Clinical Neuroscience & Medical Research Council Mitochondrial Biology UnitSchool of Clinical Medicine, University of CambridgeCambridgeUK
| | - Lizbeth Hedstrom
- Department of BiologyBrandeis UniversityWalthamMA
- Department of ChemistryBrandeis University, 415 South St.WalthamMA
| | - Antonella Spinazzola
- Department of Clinical and Movement Neurosciences, UCL Queens Square Institute of Neurology, Royal Free CampusUniversity College LondonLondonUK
- MRC Centre for Neuromuscular DiseasesUCL Institute of Neurology and National Hospital for Neurology and NeurosurgeryLondonUK
| | - Robert W. Taylor
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Gráinne S. Gorman
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
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30
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Singh R, Manivannan S, Krikken AM, de Boer R, Bordin N, Devos DP, van der Klei IJ. Hansenula polymorpha Pex37 is a peroxisomal membrane protein required for organelle fission and segregation. FEBS J 2019; 287:1742-1757. [PMID: 31692262 PMCID: PMC7318627 DOI: 10.1111/febs.15123] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 08/29/2019] [Accepted: 11/04/2019] [Indexed: 11/30/2022]
Abstract
Here, we describe a novel peroxin, Pex37, in the yeast Hansenula polymorpha. H. polymorpha Pex37 is a peroxisomal membrane protein, which belongs to a protein family that includes, among others, the Neurospora crassa Woronin body protein Wsc, the human peroxisomal membrane protein PXMP2, the Saccharomyces cerevisiae mitochondrial inner membrane protein Sym1, and its mammalian homologue MPV17. We show that deletion of H. polymorpha PEX37 does not appear to have a significant effect on peroxisome biogenesis or proliferation in cells grown at peroxisome‐inducing growth conditions (methanol). However, the absence of Pex37 results in a reduction in peroxisome numbers and a defect in peroxisome segregation in cells grown at peroxisome‐repressing conditions (glucose). Conversely, overproduction of Pex37 in glucose‐grown cells results in an increase in peroxisome numbers in conjunction with a decrease in their size. The increase in numbers in PEX37‐overexpressing cells depends on the dynamin‐related protein Dnm1. Together our data suggest that Pex37 is involved in peroxisome fission in glucose‐grown cells. Introduction of human PXMP2 in H. polymorpha pex37 cells partially restored the peroxisomal phenotype, indicating that PXMP2 represents a functional homologue of Pex37. H.polymorpha pex37 cells did not show aberrant growth on any of the tested carbon and nitrogen sources that are metabolized by peroxisomal enzymes, suggesting that Pex37 may not fulfill an essential function in transport of these substrates or compounds required for their metabolism across the peroxisomal membrane.
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Affiliation(s)
- Ritika Singh
- Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, the Netherlands
| | - Selvambigai Manivannan
- Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, the Netherlands
| | - Arjen M Krikken
- Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, the Netherlands
| | - Rinse de Boer
- Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, the Netherlands
| | - Nicola Bordin
- Centro Andaluz de Biología del Desarrollo, CSIC, Universidad Pablo de Olavide, Seville, Spain.,Structural and Molecular Biology, University College London, UK
| | - Damien P Devos
- Centro Andaluz de Biología del Desarrollo, CSIC, Universidad Pablo de Olavide, Seville, Spain
| | - Ida J van der Klei
- Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, the Netherlands
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31
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Mahjoub G, Habibzadeh P, Dastsooz H, Mirzaei M, Kavosi A, Jamali L, Javanmardi H, Katibeh P, Faghihi MA, Dastgheib SA. Clinical and molecular characterization of three patients with Hepatocerebral form of mitochondrial DNA depletion syndrome: a case series. BMC MEDICAL GENETICS 2019; 20:167. [PMID: 31664948 PMCID: PMC6819644 DOI: 10.1186/s12881-019-0893-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 09/10/2019] [Indexed: 12/31/2022]
Abstract
Background Mitochondrial DNA depletion syndromes (MDS) are clinically and phenotypically heterogeneous disorders resulting from nuclear gene mutations. The affected individuals represent a notable reduction in mitochondrial DNA (mtDNA) content, which leads to malfunction of the components of the respiratory chain. MDS is classified according to the type of affected tissue; the most common type is hepatocerebral form, which is attributed to mutations in nuclear genes such as DGUOK and MPV17. These two genes encode mitochondrial proteins and play major roles in mtDNA synthesis. Case presentation In this investigation patients in three families affected by hepatocerebral form of MDS who were initially diagnosed with tyrosinemia underwent full clinical evaluation. Furthermore, the causative mutations were identified using next generation sequencing and were subsequently validated using sanger sequencing. The effect of the mutations on the gene expression was also studied using real-time PCR. A pathogenic heterozygous frameshift deletion mutation in DGUOK gene was identified in parents of two affected patients (c.706–707 + 2 del: p.k236 fs) presenting with jaundice, impaired fetal growth, low-birth weight, and failure to thrive who died at the age of 3 and 6 months in family I. Moreover, a novel splice site mutation in MPV17 gene (c.461 + 1G > C) was identified in a patient with jaundice, muscle weakness, and failure to thrive who died due to hepatic failure at the age of 4 months. A 5-month-old infant presenting with jaundice, dark urine, poor sucking, and feeding problems was also identified to have another novel mutation in MPV17 gene leading to stop gain mutation (c.277C > T: p.(Gln93*)). Conclusions These patients had overlapping clinical features with tyrosinemia. MDS should be considered a differential diagnosis in patients presenting with signs and symptoms of tyrosinemia.
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Affiliation(s)
- Ghazale Mahjoub
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Parham Habibzadeh
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran.,Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Hassan Dastsooz
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran.,Italian Institute for Genomic Medicine (IIGM), University of Turin, Turin, Italy
| | - Malihe Mirzaei
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Arghavan Kavosi
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Laila Jamali
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Haniyeh Javanmardi
- Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Pegah Katibeh
- Department of Pediatrics, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad Ali Faghihi
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran.,Center for Therapeutic Innovation, Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, Miami, USA
| | - Seyed Alireza Dastgheib
- Department of Medical Genetics, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
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32
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Baechler SA, Dalla Rosa I, Spinazzola A, Pommier Y. Beyond the unwinding: role of TOP1MT in mitochondrial translation. Cell Cycle 2019; 18:2377-2384. [PMID: 31345095 DOI: 10.1080/15384101.2019.1646563] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Mitochondria contain their own genome (mtDNA), encoding 13 proteins of the enzyme complexes of the oxidative phosphorylation. Synthesis of these 13 mitochondrial proteins requires a specific translation machinery, the mitoribosomes whose RNA components are encoded by the mtDNA, whereas more than 80 proteins are encoded by nuclear genes. It has been well established that mitochondrial topoisomerase I (TOP1MT) is important for mtDNA integrity and mitochondrial transcription as it prevents excessive mtDNA negative supercoiling and releases topological stress during mtDNA replication and transcription. We recently showed that TOP1MT also supports mitochondrial protein synthesis, and thus is critical for promoting tumor growth. Impaired mitochondrial protein synthesis leads to activation of the mitonuclear stress response through the transcription factor ATF4, and induces cytoprotective genes in order to prevent mitochondrial and cellular dysfunction. In this perspective, we highlight the novel role of TOP1MT in mitochondrial protein synthesis and as potential target for chemotherapy.
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Affiliation(s)
- Simone A Baechler
- Laboratory of Molecular Pharmacology, Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, NIH , Bethesda , MD , USA
| | - Ilaria Dalla Rosa
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology , London , UK
| | - Antonella Spinazzola
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology , London , UK
| | - Yves Pommier
- Laboratory of Molecular Pharmacology, Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, NIH , Bethesda , MD , USA
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Blázquez-Bermejo C, Molina-Granada D, Vila-Julià F, Jiménez-Heis D, Zhou X, Torres-Torronteras J, Karlsson A, Martí R, Cámara Y. Age-related metabolic changes limit efficacy of deoxynucleoside-based therapy in thymidine kinase 2-deficient mice. EBioMedicine 2019; 46:342-355. [PMID: 31351931 PMCID: PMC6711114 DOI: 10.1016/j.ebiom.2019.07.042] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/05/2019] [Accepted: 07/15/2019] [Indexed: 01/01/2023] Open
Abstract
Background Thymidine kinase 2 (TK2) catalyses the phosphorylation of deoxythymidine (dThd) and deoxycytidine (dCtd) within mitochondria. TK2 deficiency leads to mtDNA depletion or accumulation of multiple deletions. In patients, TK2 mutations typically manifest as a rapidly progressive myopathy with infantile onset, leading to respiratory insufficiency and encephalopathy in the most severe clinical presentations. TK2-deficient mice develop the most severe form of the disease and die at average postnatal day 16. dThd+dCtd administration delayed disease progression and expanded lifespan of a knockin murine model of the disease. Methods We daily administered TK2 knockout mice (Tk2KO) from postnatal day 4 with equimolar doses of dThd+dCtd, dTMP+dCMP, dThd alone or dCtd alone. We monitored body weight and survival and studied different variables at 12 or 29 days of age. We determined metabolite levels in plasma and target tissues, mtDNA copy number in tissues, and the expression and activities of enzymes with a relevant role in mitochondrial dNTP anabolism or catabolism. Findings dThd+dCtd treatment extended average lifespan of Tk2KO mice from 16 to 34 days, attenuated growth retardation, and rescued mtDNA depletion in skeletal muscle and other target tissues of 12-day-old mice, except in brain. However, the treatment was ineffective in 29-day-old mice that still died prematurely. Bioavailability of dThd and dCtd markedly decreased during mouse development. Activity of enzymes catabolizing dThd and dCtd increased with age in small intestine. Conversely, the activity of the anabolic enzymes decreased in target tissues during mouse development. We also found that administration of dThd alone had the same impact on survival to that of dThd+dCtd, whereas dCtd alone had no influence on lifespan. Interpretation dThd+dCtd treatment recruits alternative cytosolic salvage pathways for dNTP synthesis, suggesting that this therapy would be of benefit for any Tk2 mutation. dThd accounts for the therapeutic effect of the combined treatment in mice. During the first weeks after birth, mice experience marked tissue-specific metabolic regulations and ontogenetic changes in dNTP metabolism-related enzymes that limit therapeutic efficacy to early developmental stages. Fund This study was funded by grants from the Spanish Ministry of Industry, Economy and Competitiveness, the Spanish Instituto de Salud Carlos III, the Fundación Inocente, Inocente, AFM Téléthon and the Generalitat de Catalunya. The disclosed funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
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Affiliation(s)
- Cora Blázquez-Bermejo
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Spain; Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - David Molina-Granada
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Spain; Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Ferran Vila-Julià
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Spain; Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Daniel Jiménez-Heis
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Xiaoshan Zhou
- Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institute, Karolinska University Hospital, 141 86 Stockholm, Sweden
| | - Javier Torres-Torronteras
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Spain; Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Anna Karlsson
- Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institute, Karolinska University Hospital, 141 86 Stockholm, Sweden
| | - Ramon Martí
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Spain; Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Yolanda Cámara
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Spain; Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.
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Souza PVS, Bortholin T, Teixeira CAC, Seneor DD, Marin VDGB, Dias RB, Farias IB, Badia BML, Silva LHL, Pinto WBVR, Oliveira ASB, DiMauro S. Leigh syndrome caused by mitochondrial DNA-maintenance defects revealed by whole exome sequencing. Mitochondrion 2019; 49:25-34. [PMID: 31271879 DOI: 10.1016/j.mito.2019.06.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 11/17/2018] [Accepted: 06/24/2019] [Indexed: 01/30/2023]
Abstract
Leigh syndrome represents a complex inherited neurometabolic and neurodegenerative disorder associated with different clinical, genetic and neuroimaging findings in the context of bilateral symmetrical lesions involving the brainstem and basal ganglia. Heterogeneous neurological manifestations such as spasticity, cerebellar ataxia, dystonia, choreoathetosis and parkinsonism are associated with multisystemic and ophthalmological abnormalities due to >75 different monogenic causes. Here, we describe the clinical and genetic features of a Brazilian cohort of patients with Leigh Syndrome in which muscle biopsy analysis showed mitochondrial DNA defects and determine the utility of whole exome sequencing for a final genetic diagnostic in this cohort.
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Affiliation(s)
- P V S Souza
- Division of Neuromuscular Diseases, Department of Neurology, Department of Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil.
| | - Thiago Bortholin
- Division of Neuromuscular Diseases, Department of Neurology, Department of Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Carlos Alberto Castro Teixeira
- Division of Neuromuscular Diseases, Department of Neurology, Department of Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Daniel Delgado Seneor
- Division of Neuromuscular Diseases, Department of Neurology, Department of Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Vitor Dias Gomes Barrios Marin
- Division of Neuromuscular Diseases, Department of Neurology, Department of Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Renan Braido Dias
- Division of Neuromuscular Diseases, Department of Neurology, Department of Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Igor Braga Farias
- Division of Neuromuscular Diseases, Department of Neurology, Department of Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - B M L Badia
- Division of Neuromuscular Diseases, Department of Neurology, Department of Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Luiz Henrique Libardi Silva
- Division of Neuromuscular Diseases, Department of Neurology, Department of Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - W B V R Pinto
- Division of Neuromuscular Diseases, Department of Neurology, Department of Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Acary Souza Bulle Oliveira
- Division of Neuromuscular Diseases, Department of Neurology, Department of Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Salvatore DiMauro
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
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35
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Carreño-Gago L, Blázquez-Bermejo C, Díaz-Manera J, Cámara Y, Gallardo E, Martí R, Torres-Torronteras J, García-Arumí E. Identification and Characterization of New RNASEH1 Mutations Associated With PEO Syndrome and Multiple Mitochondrial DNA Deletions. Front Genet 2019; 10:576. [PMID: 31258551 PMCID: PMC6588129 DOI: 10.3389/fgene.2019.00576] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 05/31/2019] [Indexed: 12/13/2022] Open
Abstract
Mitochondrial DNA (mtDNA) depletion and deletion syndrome encompasses a group of disorders caused by mutations in genes involved in mtDNA replication and maintenance. The clinical phenotype ranges from fatal infantile hepatocerebral forms to mild adult onset progressive external ophthalmoplegia (PEO). We report the case of a patient with PEO and multiple mtDNA deletions, with two new homozygous mutations in RNASEH1. The first mutation (c.487T>C) is located in the same catalytic domain as the four previously reported mutations, and the second (c.258_260del) is located in the connection domain, where no mutations have been reported. In silico study of the mutations predicted only the first mutation as pathogenic, but functional studies showed that both mutations cause loss of ribonuclease H1 activity. mtDNA replication dysfunction was demonstrated in patient fibroblasts, which were unable to recover normal mtDNA copy number after ethidium bromide-induced mtDNA depletion. Our results demonstrate the pathogenicity of two new RNASEH1 variants found in a patient with PEO syndrome, multiple deletions, and mild mitochondrial myopathy.
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Affiliation(s)
- Lidia Carreño-Gago
- Departament de Patologia Mitocondrial i Neuromuscular, Hospital Universitari Vall d'Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain
| | - Cora Blázquez-Bermejo
- Departament de Patologia Mitocondrial i Neuromuscular, Hospital Universitari Vall d'Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain
| | - Jordi Díaz-Manera
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain.,Servei de Neurologia, Malalties Neuromusculars, Hospital de la Santa Creu i Sant Pau i Institut de Recerca de HSCSP, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Yolanda Cámara
- Departament de Patologia Mitocondrial i Neuromuscular, Hospital Universitari Vall d'Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain
| | - Eduard Gallardo
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain.,Servei de Neurologia, Malalties Neuromusculars, Hospital de la Santa Creu i Sant Pau i Institut de Recerca de HSCSP, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Ramon Martí
- Departament de Patologia Mitocondrial i Neuromuscular, Hospital Universitari Vall d'Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain
| | - Javier Torres-Torronteras
- Departament de Patologia Mitocondrial i Neuromuscular, Hospital Universitari Vall d'Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain
| | - Elena García-Arumí
- Departament de Patologia Mitocondrial i Neuromuscular, Hospital Universitari Vall d'Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain.,Àrea de Genètica Clínica i Molecular, Hospital Universitari Vall d'Hebron, Barcelona, Spain
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36
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Wanrooij PH, Chabes A. Ribonucleotides in mitochondrial DNA. FEBS Lett 2019; 593:1554-1565. [PMID: 31093968 DOI: 10.1002/1873-3468.13440] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 05/09/2019] [Accepted: 05/09/2019] [Indexed: 01/05/2023]
Abstract
The incorporation of ribonucleotides (rNMPs) into DNA during genome replication has gained substantial attention in recent years and has been shown to be a significant source of genomic instability. Studies in yeast and mammals have shown that the two genomes, the nuclear DNA (nDNA) and the mitochondrial DNA (mtDNA), differ with regard to their rNMP content. This is largely due to differences in rNMP repair - whereas rNMPs are efficiently removed from the nuclear genome, mitochondria lack robust mechanisms for removal of single rNMPs incorporated during DNA replication. In this minireview, we describe the processes that determine the frequency of rNMPs in the mitochondrial genome and summarise recent findings regarding the effect of incorporated rNMPs on mtDNA stability and function.
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Affiliation(s)
- Paulina H Wanrooij
- Department of Medical Biochemistry and Biophysics, Umeå University, Sweden
| | - Andrei Chabes
- Department of Medical Biochemistry and Biophysics, Umeå University, Sweden.,Laboratory for Molecular Infection Medicine Sweden, Umeå University, Sweden
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37
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Durigon R, Mitchell AL, Jones AW, Manole A, Mennuni M, Hirst EM, Houlden H, Maragni G, Lattante S, Doronzio PN, Dalla Rosa I, Zollino M, Holt IJ, Spinazzola A. LETM1 couples mitochondrial DNA metabolism and nutrient preference. EMBO Mol Med 2019; 10:emmm.201708550. [PMID: 30012579 PMCID: PMC6127893 DOI: 10.15252/emmm.201708550] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The diverse clinical phenotypes of Wolf–Hirschhorn syndrome (WHS) are the result of haploinsufficiency of several genes, one of which, LETM1, encodes a protein of the mitochondrial inner membrane of uncertain function. Here, we show that LETM1 is associated with mitochondrial ribosomes, is required for mitochondrial DNA distribution and expression, and regulates the activity of an ancillary metabolic enzyme, pyruvate dehydrogenase. LETM1 deficiency in WHS alters mitochondrial morphology and DNA organization, as does substituting ketone bodies for glucose in control cells. While this change in nutrient availability leads to the death of fibroblasts with normal amounts of LETM1, WHS‐derived fibroblasts survive on ketone bodies, which can be attributed to their reduced dependence on glucose oxidation. Thus, remodeling of mitochondrial nucleoprotein complexes results from the inability of mitochondria to use specific substrates for energy production and is indicative of mitochondrial dysfunction. However, the dysfunction could be mitigated by a modified diet—for WHS, one high in lipids and low in carbohydrates.
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Affiliation(s)
- Romina Durigon
- Department of Clinical and Movement Neurosciences, UCL Institute of Neurology, London, UK
| | - Alice L Mitchell
- Department of Clinical and Movement Neurosciences, UCL Institute of Neurology, London, UK
| | - Aleck We Jones
- Department of Clinical and Movement Neurosciences, UCL Institute of Neurology, London, UK
| | - Andreea Manole
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK.,Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Mara Mennuni
- Department of Clinical and Movement Neurosciences, UCL Institute of Neurology, London, UK
| | | | - Henry Houlden
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK.,Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | | | - Serena Lattante
- Institute of Genomic Medicine, Catholic University, Rome, Italy
| | | | - Ilaria Dalla Rosa
- Department of Clinical and Movement Neurosciences, UCL Institute of Neurology, London, UK
| | | | - Ian J Holt
- Department of Clinical and Movement Neurosciences, UCL Institute of Neurology, London, UK.,Biodonostia Health Research Institute, San Sebastián, Spain.,IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Antonella Spinazzola
- Department of Clinical and Movement Neurosciences, UCL Institute of Neurology, London, UK .,MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK
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38
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Martorano L, Peron M, Laquatra C, Lidron E, Facchinello N, Meneghetti G, Tiso N, Rasola A, Ghezzi D, Argenton F. The zebrafish orthologue of the human hepatocerebral disease gene MPV17 plays pleiotropic roles in mitochondria. Dis Model Mech 2019; 12:dmm.037226. [PMID: 30833296 PMCID: PMC6451431 DOI: 10.1242/dmm.037226] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 02/25/2019] [Indexed: 12/12/2022] Open
Abstract
Mitochondrial DNA depletion syndromes (MDS) are a group of rare autosomal recessive disorders with early onset and no cure available. MDS are caused by mutations in nuclear genes involved in mitochondrial DNA (mtDNA) maintenance, and characterized by both a strong reduction in mtDNA content and severe mitochondrial defects in affected tissues. Mutations in MPV17, a nuclear gene encoding a mitochondrial inner membrane protein, have been associated with hepatocerebral forms of MDS. The zebrafish mpv17 null mutant lacks the guanine-based reflective skin cells named iridophores and represents a promising model to clarify the role of Mpv17. In this study, we characterized the mitochondrial phenotype of mpv17−/− larvae and found early and severe ultrastructural alterations in liver mitochondria, as well as significant impairment of the respiratory chain, leading to activation of the mitochondrial quality control. Our results provide evidence for zebrafish Mpv17 being essential for maintaining mitochondrial structure and functionality, while its effects on mtDNA copy number seem to be subordinate. Considering that a role in nucleotide availability had already been postulated for MPV17, that embryos blocked in pyrimidine synthesis do phenocopy mpv17−/− knockouts (KOs) and that mpv17−/− KOs have impaired Dihydroorotate dehydrogenase activity, we provided mpv17 mutants with the pyrimidine precursor orotic acid (OA). Treatment with OA, an easily available food supplement, significantly increased both iridophore number and mtDNA content in mpv17−/− mutants, thus linking the loss of Mpv17 to pyrimidine de novo synthesis and opening a new simple therapeutic approach for MPV17-related MDS. Summary: The zebrafish mpv17−/− mutant shows a severe mitochondrial phenotype with ultrastructural alterations and oxidative phosphorylation impairment. The pyrimidine precursor orotic acid ameliorates mpv17−/− phenotype and increases mitochondrial DNA content, linking the loss of Mpv17 to pyrimidine de novo synthesis.
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Affiliation(s)
- Laura Martorano
- Department of Biology, University of Padova, Via Ugo Bassi, 58/B, 35131 Padova, Italy
| | - Margherita Peron
- Department of Biology, University of Padova, Via Ugo Bassi, 58/B, 35131 Padova, Italy
| | - Claudio Laquatra
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi, 58/B, 35131 Padova, Italy
| | - Elisa Lidron
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi, 58/B, 35131 Padova, Italy
| | - Nicola Facchinello
- Department of Biology, University of Padova, Via Ugo Bassi, 58/B, 35131 Padova, Italy
| | - Giacomo Meneghetti
- Department of Biology, University of Padova, Via Ugo Bassi, 58/B, 35131 Padova, Italy
| | - Natascia Tiso
- Department of Biology, University of Padova, Via Ugo Bassi, 58/B, 35131 Padova, Italy
| | - Andrea Rasola
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi, 58/B, 35131 Padova, Italy
| | - Daniele Ghezzi
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Via Amadeo 42, 20133 Milan, Italy.,Department of Pathophysiology and Transplantation, University of Milan, Via Libero Temolo 4, 20126 Milan, Italy
| | - Francesco Argenton
- Department of Biology, University of Padova, Via Ugo Bassi, 58/B, 35131 Padova, Italy
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Blázquez-Bermejo C, Carreño-Gago L, Molina-Granada D, Aguirre J, Ramón J, Torres-Torronteras J, Cabrera-Pérez R, Martín MÁ, Domínguez-González C, de la Cruz X, Lombès A, García-Arumí E, Martí R, Cámara Y. Increased dNTP pools rescue mtDNA depletion in human POLG-deficient fibroblasts. FASEB J 2019; 33:7168-7179. [PMID: 30848931 DOI: 10.1096/fj.201801591r] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Polymerase γ catalytic subunit (POLG) gene encodes the enzyme responsible for mitochondrial DNA (mtDNA) synthesis. Mutations affecting POLG are the most prevalent cause of mitochondrial disease because of defective mtDNA replication and lead to a wide spectrum of clinical phenotypes characterized by mtDNA deletions or depletion. Enhancing mitochondrial deoxyribonucleoside triphosphate (dNTP) synthesis effectively rescues mtDNA depletion in different models of defective mtDNA maintenance due to dNTP insufficiency. In this study, we studied mtDNA copy number recovery rates following ethidium bromide-forced depletion in quiescent fibroblasts from patients harboring mutations in different domains of POLG. Whereas control cells spontaneously recovered initial mtDNA levels, POLG-deficient cells experienced a more severe depletion and could not repopulate mtDNA. However, activation of deoxyribonucleoside (dN) salvage by supplementation with dNs plus erythro-9-(2-hydroxy-3-nonyl) adenine (inhibitor of deoxyadenosine degradation) led to increased mitochondrial dNTP pools and promoted mtDNA repopulation in all tested POLG-mutant cells independently of their specific genetic defect. The treatment did not compromise POLG fidelity because no increase in multiple deletions or point mutations was detected. Our study suggests that physiologic dNTP concentration limits the mtDNA replication rate. We thus propose that increasing mitochondrial dNTP availability could be of therapeutic interest for POLG deficiency and other conditions in which mtDNA maintenance is challenged.-Blázquez-Bermejo, C., Carreño-Gago, L., Molina-Granada, D., Aguirre, J., Ramón, J., Torres-Torronteras, J., Cabrera-Pérez, R., Martín, M. Á., Domínguez-González, C., de la Cruz, X., Lombès, A., García-Arumí, E., Martí, R., Cámara, Y. Increased dNTP pools rescue mtDNA depletion in human POLG-deficient fibroblasts.
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Affiliation(s)
- Cora Blázquez-Bermejo
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca-Universitat Autònoma de Barcelona, Barcelona, Spain.,Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Lidia Carreño-Gago
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca-Universitat Autònoma de Barcelona, Barcelona, Spain.,Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - David Molina-Granada
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca-Universitat Autònoma de Barcelona, Barcelona, Spain.,Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Josu Aguirre
- Translational Bioinformatics Group, Vall d'Hebron Institut de Recerca-Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Javier Ramón
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca-Universitat Autònoma de Barcelona, Barcelona, Spain.,Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Javier Torres-Torronteras
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca-Universitat Autònoma de Barcelona, Barcelona, Spain.,Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Raquel Cabrera-Pérez
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca-Universitat Autònoma de Barcelona, Barcelona, Spain.,Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Miguel Ángel Martín
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.,Laboratorio de Enfermedades Mitocondriales, Instituto de Investigación Hospital 12 de Octubre (i+12), Madrid, Spain
| | - Cristina Domínguez-González
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.,Unidad de Neuromuscular, Instituto de Investigación Hospital 12 de Octubre (i+12), Madrid, Spain
| | - Xavier de la Cruz
- Translational Bioinformatics Group, Vall d'Hebron Institut de Recerca-Universitat Autònoma de Barcelona, Barcelona, Spain.,Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain; and
| | - Anne Lombès
- Institut Cochin, INSERM Unité 1016-Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 8104-Service de Biochimie Métabolique et Centre de Génétique Moléculaire et Chromosomique, Groupement Hospitalier Universitaire (GHU) Pitié-Salpétrière, Assistance Publique-Hôpitaux de Paris (AP-HP)-Université Paris Descartes, Paris, France
| | - Elena García-Arumí
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca-Universitat Autònoma de Barcelona, Barcelona, Spain.,Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Ramon Martí
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca-Universitat Autònoma de Barcelona, Barcelona, Spain.,Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Yolanda Cámara
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca-Universitat Autònoma de Barcelona, Barcelona, Spain.,Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
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Guha M, Srinivasan S, Johnson FB, Ruthel G, Guja K, Garcia-Diaz M, Kaufman BA, Glineburg MR, Fang J, Nakagawa H, Basha J, Kundu T, Avadhani NG. hnRNPA2 mediated acetylation reduces telomere length in response to mitochondrial dysfunction. PLoS One 2018; 13:e0206897. [PMID: 30427907 PMCID: PMC6241121 DOI: 10.1371/journal.pone.0206897] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Accepted: 10/22/2018] [Indexed: 11/19/2022] Open
Abstract
Telomeres protect against chromosomal damage. Accelerated telomere loss has been associated with premature aging syndromes such as Werner's syndrome and Dyskeratosis Congenita, while, progressive telomere loss activates a DNA damage response leading to chromosomal instability, typically observed in cancer cells and senescent cells. Therefore, identifying mechanisms of telomere length maintenance is critical for understanding human pathologies. In this paper we demonstrate that mitochondrial dysfunction plays a causal role in telomere shortening. Furthermore, hnRNPA2, a mitochondrial stress responsive lysine acetyltransferase (KAT) acetylates telomere histone H4at lysine 8 of (H4K8) and this acetylation is associated with telomere attrition. Cells containing dysfunctional mitochondria have higher telomere H4K8 acetylation and shorter telomeres independent of cell proliferation rates. Ectopic expression of KAT mutant hnRNPA2 rescued telomere length possibly due to impaired H4K8 acetylation coupled with inability to activate telomerase expression. The phenotypic outcome of telomere shortening in immortalized cells included chromosomal instability (end-fusions) and telomerase activation, typical of an oncogenic transformation; while in non-telomerase expressing fibroblasts, mitochondrial dysfunction induced-telomere attrition resulted in senescence. Our findings provide a mechanistic association between dysfunctional mitochondria and telomere loss and therefore describe a novel epigenetic signal for telomere length maintenance.
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Affiliation(s)
- Manti Guha
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Satish Srinivasan
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - F. Bradley Johnson
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Gordon Ruthel
- Penn Vet Imaging Core, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Kip Guja
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY, United States of America
| | - Miguel Garcia-Diaz
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY, United States of America
| | - Brett A. Kaufman
- Vascular Medicine Institute, University of Pittsburg, Pittsburgh, PA United States of America
| | - M. Rebecca Glineburg
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - JiKang Fang
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Hiroshi Nakagawa
- Department of Gastroenterology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Jeelan Basha
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
| | - Tapas Kundu
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
| | - Narayan G. Avadhani
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
- * E-mail:
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41
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Alonzo JR, Venkataraman C, Field MS, Stover PJ. The mitochondrial inner membrane protein MPV17 prevents uracil accumulation in mitochondrial DNA. J Biol Chem 2018; 293:20285-20294. [PMID: 30385507 DOI: 10.1074/jbc.ra118.004788] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 10/24/2018] [Indexed: 11/06/2022] Open
Abstract
Mitochondrial inner membrane protein MPV17 is a protein of unknown function that is associated with mitochondrial DNA (mtDNA)-depletion syndrome (MDS). MPV17 loss-of-function has been reported to result in tissue-specific nucleotide pool imbalances, which can occur in states of perturbed folate-mediated one-carbon metabolism (FOCM), but MPV17 has not been directly linked to FOCM. FOCM is a metabolic network that provides one-carbon units for the de novo synthesis of purine and thymidylate nucleotides (e.g. dTMP) for both nuclear DNA (nuDNA) and mtDNA replication. In this study, we investigated the impact of reduced MPV17 expression on markers of impaired FOCM in HeLa cells. Depressed MPV17 expression reduced mitochondrial folate levels by 43% and increased uracil levels, a marker of impaired dTMP synthesis, in mtDNA by 3-fold. The capacity of mitochondrial de novo and salvage pathway dTMP biosynthesis was unchanged by the reduced MPV17 expression, but the elevated levels of uracil in mtDNA suggested that other sources of mitochondrial dTMP are compromised in MPV17-deficient cells. These results indicate that MPV17 provides a third dTMP source, potentially by serving as a transporter that transfers dTMP from the cytosol to mitochondria to sustain mtDNA synthesis. We propose that MPV17 loss-of-function and related hepatocerebral MDS are linked to impaired FOCM in mitochondria by providing insufficient access to cytosolic dTMP pools and by severely reducing mitochondrial folate pools.
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Affiliation(s)
- Judith R Alonzo
- From the Graduate Field of Biochemistry, Molecular, and Cellular Biology and
| | - Chantel Venkataraman
- the Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853
| | - Martha S Field
- the Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853
| | - Patrick J Stover
- From the Graduate Field of Biochemistry, Molecular, and Cellular Biology and; the Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853.
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42
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Baumann M, Schreiber H, Schlotter‐Weigel B, Löscher WN, Stucka R, Karall D, Strom TM, Bauer P, Krabichler B, Fauth C, Glaeser D, Senderek J. MPV17
mutations in juvenile‐ and adult‐onset axonal sensorimotor polyneuropathy. Clin Genet 2018; 95:182-186. [DOI: 10.1111/cge.13462] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 07/19/2018] [Accepted: 07/30/2018] [Indexed: 01/27/2023]
Affiliation(s)
- Matthias Baumann
- Department of Pediatrics IMedical University of Innsbruck Innsbruck Austria
| | - Herbert Schreiber
- Neurological Practice Center and Neuropoint Patient Academy Ulm Germany
| | - Beate Schlotter‐Weigel
- Friedrich‐Baur‐Institute at the Department of NeurologyUniversity Hospital Munich Germany
| | - Wolfgang N. Löscher
- Clinical Department of NeurologyMedical University of Innsbruck Innsbruck Austria
| | - Rolf Stucka
- Friedrich‐Baur‐Institute at the Department of NeurologyUniversity Hospital Munich Germany
| | - Daniela Karall
- Department of Pediatrics IMedical University of Innsbruck Innsbruck Austria
| | - Tim M. Strom
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, and Institute of Human GeneticsTechnische Universität München Munich Germany
| | - Peter Bauer
- Institute for Medical Genetics and Applied Genomics Tübingen Germany
| | - Birgit Krabichler
- Division of Human GeneticsMedical University of Innsbruck Innsbruck Austria
| | - Christine Fauth
- Division of Human GeneticsMedical University of Innsbruck Innsbruck Austria
| | | | - Jan Senderek
- Friedrich‐Baur‐Institute at the Department of NeurologyUniversity Hospital Munich Germany
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43
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Landoni JC, Wang L, Suomalainen A. Quantitative solid-phase assay to measure deoxynucleoside triphosphate pools. Biol Methods Protoc 2018; 3:bpy011. [PMID: 32161804 PMCID: PMC6994031 DOI: 10.1093/biomethods/bpy011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 08/09/2018] [Accepted: 08/15/2018] [Indexed: 12/25/2022] Open
Abstract
deoxynucleoside triphosphate (dNTPs) are the reduced nucleotides used as the building blocks and energy source for deoxyribonucleic acid (DNA) replication and maintenance in all living systems. They are present in highly regulated amounts and ratios in the cell, and their balance has been implicated in the most important cell processes, from determining the fidelity of DNA replication to affecting cell fate. Furthermore, many cancer drugs target biosynthetic enzymes in dNTP metabolism, and mutations in genes directly or indirectly affecting these pathways that are the cause of devastating diseases. The accurate and systematic measurement of these pools is key to understanding the mechanisms behind these diseases and their treatment. We present a new method for measuring dNTP pools from biological samples, utilizing the current state-of-the-art polymerase method, modified to a solid-phase setting and optimized for larger scale measurements.
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Affiliation(s)
- Juan Cruz Landoni
- Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
| | - Liya Wang
- Department of Anatomy, Physiology, and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Anu Suomalainen
- Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland.,Department of Neurosciences, Helsinki University Hospital, Helsinki, Finland.,Neuroscience Center, HiLife, University of Helsinki, Helsinki, Finland
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44
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Gilberti M, Baruffini E, Donnini C, Dallabona C. Pathological alleles of MPV17 modeled in the yeast Saccharomyces cerevisiae orthologous gene SYM1 reveal their inability to take part in a high molecular weight complex. PLoS One 2018; 13:e0205014. [PMID: 30273399 PMCID: PMC6166979 DOI: 10.1371/journal.pone.0205014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 09/18/2018] [Indexed: 01/07/2023] Open
Abstract
Mitochondrial DNA depletion syndromes (MDDS) are a genetically and clinically heterogeneous group of human diseases caused by mutations in nuclear genes and characterized by a severe reduction in mitochondrial DNA (mtDNA) copy number leading to impaired energy production in affected tissues and organs. Mutations in the MPV17 gene, whose role is still elusive, were described as cause of the hepatocerebral form of MDDS and Navajo neuro-hepathopathy. The high degree of conservation observed between MPV17 and its yeast homolog SYM1 made the latter a good model for the study of the pathology. Here, we used Saccharomyces cerevisiae to elucidate the molecular consequences of seven MPV17 missense mutations identified in patients and localized in different protein domains. The phenotypic analysis of the appropriate sym1 mutant strains created demonstrated deleterious effect for all mutations regarding OXPHOS metabolism and mtDNA stability. We deepened the pathogenic effect of the mutations by investigating whether they prevented the correct protein localization into the mitochondria or affected the stability of the proteins. All the Sym1 mutant proteins correctly localized into the mitochondria and only one mutation predominantly affects protein stability. All the other mutations compromised the formation of the high molecular weight complex of unknown composition, previously identified both in yeast, cell cultures and mouse tissues, as demonstrated by the consistent fraction of the Sym1 mutant proteins found free or in not fully assembled complex, strengthening its role as protein forming part of a high molecular weight complex.
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Affiliation(s)
- Micol Gilberti
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Enrico Baruffini
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Claudia Donnini
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
- * E-mail:
| | - Cristina Dallabona
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
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45
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Mitochondrial DNA replication: clinical syndromes. Essays Biochem 2018; 62:297-308. [PMID: 29950321 DOI: 10.1042/ebc20170101] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 03/17/2018] [Accepted: 05/23/2018] [Indexed: 02/08/2023]
Abstract
Each nucleated cell contains several hundreds of mitochondria, which are unique organelles in being under dual genome control. The mitochondria contain their own DNA, the mtDNA, but most of mitochondrial proteins are encoded by nuclear genes, including all the proteins required for replication, transcription, and repair of mtDNA. MtDNA replication is a continuous process that requires coordinated action of several enzymes that are part of the mtDNA replisome. It also requires constant supply of deoxyribonucleotide triphosphates(dNTPs) and interaction with other mitochondria for mixing and unifying the mitochondrial compartment. MtDNA maintenance defects are a growing list of disorders caused by defects in nuclear genes involved in different aspects of mtDNA replication. As a result of defects in these genes, mtDNA depletion and/or multiple mtDNA deletions develop in affected tissues resulting in variable manifestations that range from adult-onset mild disease to lethal presentation early in life.
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46
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Mice lacking the mitochondrial exonuclease MGME1 accumulate mtDNA deletions without developing progeria. Nat Commun 2018; 9:1202. [PMID: 29572490 PMCID: PMC5865154 DOI: 10.1038/s41467-018-03552-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 02/21/2018] [Indexed: 12/17/2022] Open
Abstract
Replication of mammalian mitochondrial DNA (mtDNA) is an essential process that requires high fidelity and control at multiple levels to ensure proper mitochondrial function. Mutations in the mitochondrial genome maintenance exonuclease 1 (MGME1) gene were recently reported in mitochondrial disease patients. Here, to study disease pathophysiology, we generated Mgme1 knockout mice and report that homozygous knockouts develop depletion and multiple deletions of mtDNA. The mtDNA replication stalling phenotypes vary dramatically in different tissues of Mgme1 knockout mice. Mice with MGME1 deficiency accumulate a long linear subgenomic mtDNA species, similar to the one found in mtDNA mutator mice, but do not develop progeria. This finding resolves a long-standing debate by showing that point mutations of mtDNA are the main cause of progeria in mtDNA mutator mice. We also propose a role for MGME1 in the regulation of replication and transcription termination at the end of the control region of mtDNA. It has been debated whether premature ageing in mitochondrial DNA mutator mice is driven by point mutations or deletions of mtDNA. Matic et al generate Mgme1 knockout mice and show here that these mice have tissue-specific replication stalling and accumulate deleted mtDNA, without developing progeria.
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47
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Abstract
Mitochondrial DNA (mtDNA), which is essential for mitochondrial and cell function, is replicated and transcribed in the organelle by proteins that are entirely coded in the nucleus. Replication of mtDNA is challenged not only by threats related to the replication machinery and orchestration of DNA synthesis, but also by factors linked to the peculiarity of this genome. Indeed the architecture, organization, copy number, and location of mtDNA, which are markedly distinct from the nuclear genome, require ad hoc and complex regulation to ensure coordinated replication. As a consequence sub-optimal mtDNA replication, which results from compromised regulation of these factors, is generally associated with mitochondrial dysfunction and disease. Mitochondrial DNA replication should be considered in the context of the organelle and the whole cell, and not just a single genome or a single replication event. Major threats to mtDNA replication are linked to its dependence on both mitochondrial and nuclear factors, which require exquisite coordination of these crucial subcellular compartments. Moreover, regulation of replication events deals with a dynamic population of multiple mtDNA molecules rather than with a fixed number of genome copies, as it is the case for nuclear DNA. Importantly, the mechanistic aspects of mtDNA replication are still debated. We describe here major challenges for human mtDNA replication, the mechanistic aspects of the process that are to a large extent original, and their consequences on disease.
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Affiliation(s)
- Miria Ricchetti
- Institut Pasteur, Department of Developmental and Stem Cell Biology, Stem Cells and Development, 75724 Cedex15, Paris, France; Team Stability of Nuclear and Mitochondrial DNA, CNRS UMR 3738, 75724, Cedex15, Paris, France.
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48
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Moss CF, Dalla Rosa I, Hunt LE, Yasukawa T, Young R, Jones AWE, Reddy K, Desai R, Virtue S, Elgar G, Voshol P, Taylor MS, Holt IJ, Reijns MAM, Spinazzola A. Aberrant ribonucleotide incorporation and multiple deletions in mitochondrial DNA of the murine MPV17 disease model. Nucleic Acids Res 2018; 45:12808-12815. [PMID: 29106596 PMCID: PMC5728394 DOI: 10.1093/nar/gkx1009] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 10/17/2017] [Indexed: 12/24/2022] Open
Abstract
All DNA polymerases misincorporate ribonucleotides despite their preference for deoxyribonucleotides, and analysis of cultured cells indicates that mammalian mitochondrial DNA (mtDNA) tolerates such replication errors. However, it is not clear to what extent misincorporation occurs in tissues, or whether this plays a role in human disease. Here, we show that mtDNA of solid tissues contains many more embedded ribonucleotides than that of cultured cells, consistent with the high ratio of ribonucleotide to deoxynucleotide triphosphates in tissues, and that riboadenosines account for three-quarters of them. The pattern of embedded ribonucleotides changes in a mouse model of Mpv17 deficiency, which displays a marked increase in rGMPs in mtDNA. However, while the mitochondrial dGTP is low in the Mpv17−/− liver, the brain shows no change in the overall dGTP pool, leading us to suggest that Mpv17 determines the local concentration or quality of dGTP. Embedded rGMPs are expected to distort the mtDNA and impede its replication, and elevated rGMP incorporation is associated with early-onset mtDNA depletion in liver and late-onset multiple deletions in brain of Mpv17−/− mice. These findings suggest aberrant ribonucleotide incorporation is a primary mtDNA abnormality that can result in pathology.
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Affiliation(s)
| | - Ilaria Dalla Rosa
- MRC Laboratory, Mill Hill, London NW7 1AA, UK.,Department of Clinical Neurosciences, Institute of Neurology, Royal Free Campus, University College London NW3 2PF, UK
| | - Lilian E Hunt
- Advanced Sequencing Facility, Francis Crick Institute, London NW1 1AT, UK
| | | | - Robert Young
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, The University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Aleck W E Jones
- MRC Laboratory, Mill Hill, London NW7 1AA, UK.,Department of Clinical Neurosciences, Institute of Neurology, Royal Free Campus, University College London NW3 2PF, UK
| | - Kaalak Reddy
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, The University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Radha Desai
- MRC Laboratory, Mill Hill, London NW7 1AA, UK
| | - Sam Virtue
- MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge CB2 0QQ, UK
| | - Greg Elgar
- Advanced Sequencing Facility, Francis Crick Institute, London NW1 1AT, UK
| | - Peter Voshol
- MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge CB2 0QQ, UK
| | - Martin S Taylor
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, The University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Ian J Holt
- MRC Laboratory, Mill Hill, London NW7 1AA, UK.,Department of Clinical Neurosciences, Institute of Neurology, Royal Free Campus, University College London NW3 2PF, UK.,Biodonostia Health Research Institute, 20014 San Sebastián, Spain and IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
| | - Martin A M Reijns
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, The University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Antonella Spinazzola
- MRC Laboratory, Mill Hill, London NW7 1AA, UK.,Department of Clinical Neurosciences, Institute of Neurology, Royal Free Campus, University College London NW3 2PF, UK.,MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
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49
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El-Hattab AW, Wang J, Dai H, Almannai M, Staufner C, Alfadhel M, Gambello MJ, Prasun P, Raza S, Lyons HJ, Afqi M, Saleh MAM, Faqeih EA, Alzaidan HI, Alshenqiti A, Flore LA, Hertecant J, Sacharow S, Barbouth DS, Murayama K, Shah AA, Lin HC, Wong LJC. MPV17-related mitochondrial DNA maintenance defect: New cases and review of clinical, biochemical, and molecular aspects. Hum Mutat 2018; 39:461-470. [PMID: 29282788 DOI: 10.1002/humu.23387] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 12/04/2017] [Accepted: 12/15/2017] [Indexed: 02/02/2023]
Abstract
Mitochondrial DNA (mtDNA) maintenance defects are a group of diseases caused by deficiency of proteins involved in mtDNA synthesis, mitochondrial nucleotide supply, or mitochondrial dynamics. One of the mtDNA maintenance proteins is MPV17, which is a mitochondrial inner membrane protein involved in importing deoxynucleotides into the mitochondria. In 2006, pathogenic variants in MPV17 were first reported to cause infantile-onset hepatocerebral mtDNA depletion syndrome and Navajo neurohepatopathy. To date, 75 individuals with MPV17-related mtDNA maintenance defect have been reported with 39 different MPV17 pathogenic variants. In this report, we present an additional 25 affected individuals with nine novel MPV17 pathogenic variants. We summarize the clinical features of all 100 affected individuals and review the total 48 MPV17 pathogenic variants. The vast majority of affected individuals presented with an early-onset encephalohepatopathic disease characterized by hepatic and neurological manifestations, failure to thrive, lactic acidemia, and mtDNA depletion detected mainly in liver tissue. Rarely, MPV17 deficiency can cause a late-onset neuromyopathic disease characterized by myopathy and peripheral neuropathy with no or minimal liver involvement. Approximately half of the MPV17 pathogenic variants are missense. A genotype with biallelic missense variants, in particular homozygous p.R50Q, p.P98L, and p.R41Q, can carry a relatively better prognosis.
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Affiliation(s)
- Ayman W El-Hattab
- Division of Clinical Genetics and Metabolic Disorders, Pediatric Department, Tawam Hospital, Al-Ain, United Arab Emirates
| | - Julia Wang
- Medical Scientist Training Program and Program in Developmental Biology, Baylor College of Medicine, Houston, Texas
| | - Hongzheng Dai
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Mohammed Almannai
- Section of Medical Genetics, King Fahad Medical City, Children's Specialist Hospital, Riyadh, Saudi Arabia
| | - Christian Staufner
- Division of Neuropediatrics and Metabolic Medicine, Department of General Pediatrics, University Hospital Heidelberg, Heidelberg, Germany
| | - Majid Alfadhel
- King Abdullah International Medical Research Centre, King Saud bin Abdulaziz University for Health Sciences, Division of Genetics, Department of Pediatrics, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia
| | - Michael J Gambello
- Division of Medical Genetics, Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia
| | - Pankaj Prasun
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Saleem Raza
- Department of Pediatrics, St John Hospital and Medical Center and Wayne State University School of Medicine, Detroit, Michigan
| | - Hernando J Lyons
- Department of Pediatrics, St John Hospital and Medical Center and Wayne State University School of Medicine, Detroit, Michigan
| | - Manal Afqi
- Section of Medical Genetics, King Fahad Medical City, Children's Specialist Hospital, Riyadh, Saudi Arabia
| | - Mohammed A M Saleh
- Section of Medical Genetics, King Fahad Medical City, Children's Specialist Hospital, Riyadh, Saudi Arabia
| | - Eissa A Faqeih
- Section of Medical Genetics, King Fahad Medical City, Children's Specialist Hospital, Riyadh, Saudi Arabia
| | - Hamad I Alzaidan
- Department of Medical Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Abduljabbar Alshenqiti
- Department of Medical Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Leigh Anne Flore
- Division of Genetic, Genomic, and Metabolic Disorders, Children's Hospital of Michigan and Wayne State University, Detroit, Michigan
| | - Jozef Hertecant
- Division of Clinical Genetics and Metabolic Disorders, Pediatric Department, Tawam Hospital, Al-Ain, United Arab Emirates
| | - Stephanie Sacharow
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts
| | - Deborah S Barbouth
- Division of Clinical and Translational Genetics, Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami, Miller School of Medicine, Miami, Florida
| | - Kei Murayama
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Amit A Shah
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Henry C Lin
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Lee-Jun C Wong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
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50
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Regulation of Small Mitochondrial DNA Replicative Advantage by Ribonucleotide Reductase in Saccharomyces cerevisiae. G3-GENES GENOMES GENETICS 2017; 7:3083-3090. [PMID: 28717049 PMCID: PMC5592933 DOI: 10.1534/g3.117.043851] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Small mitochondrial genomes can behave as selfish elements by displacing wild-type genomes regardless of their detriment to the host organism. In the budding yeast Saccharomyces cerevisiae, small hypersuppressive mtDNA transiently coexist with wild-type in a state of heteroplasmy, wherein the replicative advantage of the small mtDNA outcompetes wild-type and produces offspring without respiratory capacity in >95% of colonies. The cytosolic enzyme ribonucleotide reductase (RNR) catalyzes the rate-limiting step in dNTP synthesis and its inhibition has been correlated with increased petite colony formation, reflecting loss of respiratory function. Here, we used heteroplasmic diploids containing wild-type (rho+) and suppressive (rho−) or hypersuppressive (HS rho−) mitochondrial genomes to explore the effects of RNR activity on mtDNA heteroplasmy in offspring. We found that the proportion of rho+ offspring was significantly increased by RNR overexpression or deletion of its inhibitor, SML1, while reducing RNR activity via SML1 overexpression produced the opposite effects. In addition, using Ex Taq and KOD Dash polymerases, we observed a replicative advantage for small over large template DNA in vitro, but only at low dNTP concentrations. These results suggest that dNTP insufficiency contributes to the replicative advantage of small mtDNA over wild-type and cytosolic dNTP synthesis by RNR is an important regulator of heteroplasmy involving small mtDNA molecules in yeast.
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