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Yazdani M. Cellular and Molecular Responses to Mitochondrial DNA Deletions in Kearns-Sayre Syndrome: Some Underlying Mechanisms. Mol Neurobiol 2024; 61:5665-5679. [PMID: 38224444 DOI: 10.1007/s12035-024-03938-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2024]
Abstract
Kearns-Sayre syndrome (KSS) is a rare multisystem mitochondrial disorder. It is caused by mitochondrial DNA (mtDNA) rearrangements, mostly large-scale deletions of 1.1-10 kb. These deletions primarily affect energy supply through impaired oxidative phosphorylation and reduced ATP production. This impairment gives rise to dysfunction of several tissues, in particular those with high energy demand like brain and muscles. Over the past decades, changes in respiratory chain complexes and energy metabolism have been emphasized, whereas little attention has been paid to other reports on ROS overproduction, protein synthesis inhibition, myelin vacuolation, demyelination, autophagy, apoptosis, and involvement of lipid raft and oligodendrocytes in KSS. Therefore, this paper draws attention towards these relatively underemphasized findings that might further clarify the pathologic cascades following deletions in the mtDNA.
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Affiliation(s)
- Mazyar Yazdani
- Department of Medical Biochemistry, Oslo University Hospital, Rikshospitalet, Oslo, 0027, Norway.
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Kidere D, Zayakin P, Livcane D, Makrecka-Kuka M, Stavusis J, Lace B, Lin TK, Liou CW, Inashkina I. Impact of the m.13513G>A Variant on the Functions of the OXPHOS System and Cell Retrograde Signaling. Curr Issues Mol Biol 2023; 45:1794-1809. [PMID: 36975485 PMCID: PMC10047405 DOI: 10.3390/cimb45030115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/08/2023] [Accepted: 02/16/2023] [Indexed: 02/24/2023] Open
Abstract
Mitochondria are involved in many vital functions in living cells, including the synthesis of ATP by oxidative phosphorylation (OXPHOS) and regulation of nuclear gene expression through retrograde signaling. Leigh syndrome is a heterogeneous neurological disorder resulting from an isolated complex I deficiency that causes damage to mitochondrial energy production. The pathogenic mitochondrial DNA (mtDNA) variant m.13513G>A has been associated with Leigh syndrome. The present study investigated the effects of this mtDNA variant on the OXPHOS system and cell retrograde signaling. Transmitochondrial cytoplasmic hybrid (cybrid) cell lines harboring 50% and 70% of the m.13513G>A variant were generated and tested along with wild-type (WT) cells. The functionality of the OXPHOS system was evaluated by spectrophotometric assessment of enzyme activity and high-resolution respirometry. Nuclear gene expression was investigated by RNA sequencing and droplet digital PCR. Increasing levels of heteroplasmy were associated with reduced OXPHOS system complex I, IV, and I + III activities, and high-resolution respirometry also showed a complex I defect. Profound changes in transcription levels of nuclear genes were observed in the cell lines harboring the pathogenic mtDNA variant, indicating the physiological processes associated with defective mitochondria.
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Affiliation(s)
- Dita Kidere
- Latvian Biomedical Research and Study Centre, LV-1067 Riga, Latvia
| | - Pawel Zayakin
- Latvian Biomedical Research and Study Centre, LV-1067 Riga, Latvia
| | - Diana Livcane
- Latvian Biomedical Research and Study Centre, LV-1067 Riga, Latvia
| | | | - Janis Stavusis
- Latvian Biomedical Research and Study Centre, LV-1067 Riga, Latvia
| | - Baiba Lace
- Latvian Biomedical Research and Study Centre, LV-1067 Riga, Latvia
- Children’s Clinical University Hospital, LV-1004 Riga, Latvia
| | - Tsu-Kung Lin
- Department of Neurology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 83305, Taiwan
- Center for Mitochondrial Research and Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 83301, Taiwan
| | - Chia-Wei Liou
- Department of Neurology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 83305, Taiwan
- Center for Mitochondrial Research and Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 83301, Taiwan
| | - Inna Inashkina
- Latvian Biomedical Research and Study Centre, LV-1067 Riga, Latvia
- Correspondence:
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Atilano SR, Udar N, Satalich TA, Udar V, Chwa M, Kenney MC. Low frequency mitochondrial DNA heteroplasmy SNPs in blood, retina, and [RPE+choroid] of age-related macular degeneration subjects. PLoS One 2021; 16:e0246114. [PMID: 33513185 PMCID: PMC7846006 DOI: 10.1371/journal.pone.0246114] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 01/13/2021] [Indexed: 01/07/2023] Open
Abstract
Purpose Mitochondrial (mt) DNA damage is associated with age-related macular degeneration (AMD) and other human aging diseases. This study was designed to quantify and characterize mtDNA low-frequency heteroplasmy single nucleotide polymorphisms (SNPs) of three different tissues isolated from AMD subjects using Next Generation Sequencing (NGS) technology. Methods DNA was extracted from neural retina, [RPE+choroid] and blood from three deceased age-related macular degeneration (AMD) subjects. Entire mitochondrial genomes were analyzed for low-frequency heteroplasmy SNPs using NGS technology that independently sequenced both mtDNA strands. This deep sequencing method (average sequencing depth of 30,000; range 1,000–100,000) can accurately differentiate low-frequency heteroplasmy SNPs from DNA modification artifacts. Twenty-three ‘hot-spot’ heteroplasmy mtDNA SNPs were analyzed in 222 additional blood samples. Results Germline homoplasmy SNPs that defined mtDNA haplogroups were consistent in the three tissues of each subject. Analyses of SNPs with <40% heteroplasmy revealed the blood had significantly greater numbers of heteroplasmy SNPs than retina alone (p≤0.05) or retina+choroid combined (p = 0.008). Twenty-three ‘hot-spot’ mtDNA heteroplasmy SNPs were present, with three being non-synonymous (amino acid change). Four ‘hot-spot’ heteroplasmy SNPs (m.1120C>T, m.1284T>C, m.1556C>T, m.7256C>T) were found in additional samples (n = 222). Five heteroplasmy SNPs (m.4104A>G, m.5320C>T, m.5471G>A, m.5474A>G, m.5498A>G) declined with age. Two heteroplasmy SNPs (m.13095T>C, m.13105A>G) increased in AMD compared to Normal samples. In the heteroplasmy SNPs, very few transversion mutations (purine to pyrimidine or vice versa, associated with oxidative damage) were found and the majority were transition changes (purine to purine or pyrimidine to pyrimidine, associated with replication errors). Conclusion Within an individual, the blood, retina and [RPE+choroid] contained identical homoplasmy SNPs representing inherited germline mtDNA haplogroup. NGS methodology showed significantly more mtDNA heteroplasmy SNPs in blood compared to retina and [RPE+choroid], suggesting the latter tissues have substantial protection. Significantly higher heteroplasmy levels of m.13095T>C and m.13105A>G may represent potential AMD biomarkers. Finally, high levels of transition mutations suggest that accumulation of heteroplasmic SNPs may occur through replication errors rather than oxidative damage.
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Affiliation(s)
- Shari R. Atilano
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA, United States of America
| | - Nitin Udar
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA, United States of America
| | - Timothy A. Satalich
- Institute for Mathematical Behavioral Science, University of California Irvine, Irvine, CA, United States of America
| | - Viraat Udar
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA, United States of America
| | - Marilyn Chwa
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA, United States of America
| | - M. Cristina Kenney
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA, United States of America
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, CA, United States of America
- * E-mail:
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Ranganathan A, Owiredu S, Jang DH, Eckmann DM. Prophylaxis of mitochondrial dysfunction caused by cellular decompression from hyperbaric exposure. Mitochondrion 2020; 52:8-19. [PMID: 32045716 DOI: 10.1016/j.mito.2020.02.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 01/24/2020] [Accepted: 02/07/2020] [Indexed: 02/07/2023]
Abstract
Mitochondrial dysfunction occurring in response to cellular perturbations can include altered mitochondrial motility and bioenergetic function having intracellular heterogeneity. Exogenous mitochondrial directed therapy may correct these dysfunctions. Using in vitro approaches, we find that cell perturbations induced by rapid decompression from hyperbaric conditions with specific gas exposures has differential effects on mitochondrial motility, inner membrane potential, cellular respiration, reactive oxygen species production, impaired maintenance of cell shape and altered intracellular distribution of bioenergetic capacity in perinuclear and cell peripheral domains. Addition of a first-generation cell-permeable succinate prodrug to support mitochondrial function has positive overall effects in blunting the resultant bioenergy responses. Our results with this model of perturbed cell function induced by rapid decompression indicate that alterations in bioenergetic state are partitioned within the cell, as directly assessed by a combination of mitochondrial respiration and dynamics measurements. Reductions in the observed level of dysfunction produced can be achieved with application of the cell-permeable succinate prodrug.
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Affiliation(s)
- Abhay Ranganathan
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Shawn Owiredu
- Department of Emergency Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - David H Jang
- Department of Emergency Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - David M Eckmann
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States; Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA 19104, United States.
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Meseguer S, Panadero J, Navarro-González C, Villarroya M, Boutoual R, Comi GP, Armengod ME. The MELAS mutation m.3243A>G promotes reactivation of fetal cardiac genes and an epithelial-mesenchymal transition-like program via dysregulation of miRNAs. Biochim Biophys Acta Mol Basis Dis 2018; 1864:3022-3037. [PMID: 29928977 DOI: 10.1016/j.bbadis.2018.06.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 05/25/2018] [Accepted: 06/13/2018] [Indexed: 12/25/2022]
Abstract
The pathomechanisms underlying oxidative phosphorylation (OXPHOS) diseases are not well-understood, but they involve maladaptive changes in mitochondria-nucleus communication. Many studies on the mitochondria-nucleus cross-talk triggered by mitochondrial dysfunction have focused on the role played by regulatory proteins, while the participation of miRNAs remains poorly explored. MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) is mostly caused by mutation m.3243A>G in mitochondrial tRNALeu(UUR) gene. Adverse cardiac and neurological events are the commonest causes of early death in m.3243A>G patients. Notably, the incidence of major clinical features associated with this mutation has been correlated to the level of m.3243A>G mutant mitochondrial DNA (heteroplasmy) in skeletal muscle. In this work, we used a transmitochondrial cybrid model of MELAS (100% m.3243A>G mutant mitochondrial DNA) to investigate the participation of miRNAs in the mitochondria-nucleus cross-talk associated with OXPHOS dysfunction. High-throughput analysis of small-RNA-Seq data indicated that expression of 246 miRNAs was significantly altered in MELAS cybrids. Validation of selected miRNAs, including miR-4775 and miR-218-5p, in patient muscle samples revealed miRNAs whose expression declined with high levels of mutant heteroplasmy. We show that miR-218-5p and miR-4775 are direct regulators of fetal cardiac genes such as NODAL, RHOA, ISL1 and RXRB, which are up-regulated in MELAS cybrids and in patient muscle samples with heteroplasmy above 60%. Our data clearly indicate that TGF-β superfamily signaling and an epithelial-mesenchymal transition-like program are activated in MELAS cybrids, and suggest that down-regulation of miRNAs regulating fetal cardiac genes is a risk marker of heart failure in patients with OXPHOS diseases.
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Affiliation(s)
- Salvador Meseguer
- RNA Modification and Mitochondrial Diseases Laboratory, Centro de Investigación Príncipe Felipe (CIPF), Carrer d'Eduardo Primo Yúfera 3, Valencia 46012, Spain.
| | - Joaquin Panadero
- Unidad de Genómica, Instituto de Investigación Sanitaria La Fe, Avenida Fernando Abril Martorell, 106 Torre A 7ª planta, Valencia 46026, Spain.
| | - Carmen Navarro-González
- RNA Modification and Mitochondrial Diseases Laboratory, Centro de Investigación Príncipe Felipe (CIPF), Carrer d'Eduardo Primo Yúfera 3, Valencia 46012, Spain.
| | - Magda Villarroya
- RNA Modification and Mitochondrial Diseases Laboratory, Centro de Investigación Príncipe Felipe (CIPF), Carrer d'Eduardo Primo Yúfera 3, Valencia 46012, Spain.
| | - Rachid Boutoual
- RNA Modification and Mitochondrial Diseases Laboratory, Centro de Investigación Príncipe Felipe (CIPF), Carrer d'Eduardo Primo Yúfera 3, Valencia 46012, Spain.
| | - Giacomo Pietro Comi
- Dino Ferrari Centre, Department of Pathophysiology and Transplantation (DEPT), University of Milan, I.R.C.C.S. Foundation Ca' Granda, Ospedale Maggiore Policlinico, via F. Sforza 35, 20122 Milan, Italy.
| | - M-Eugenia Armengod
- RNA Modification and Mitochondrial Diseases Laboratory, Centro de Investigación Príncipe Felipe (CIPF), Carrer d'Eduardo Primo Yúfera 3, Valencia 46012, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER) node 721, Madrid 28029, Spain.
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Jang DH, Seeger SC, Grady ME, Shofer FS, Eckmann DM. Mitochondrial dynamics and respiration within cells with increased open pore cytoskeletal meshes. Biol Open 2017; 6:1831-1839. [PMID: 29109116 PMCID: PMC5769657 DOI: 10.1242/bio.029009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The cytoskeletal architecture directly affects the morphology, motility, and tensional homeostasis of the cell. In addition, the cytoskeleton is important for mitosis, intracellular traffic, organelle motility, and even cellular respiration. The organelle responsible for a majority of the energy conversion for the cell, the mitochondrion, has a dependence on the cytoskeleton for mobility and function. In previous studies, we established that cytoskeletal inhibitors altered the movement of the mitochondria, their morphology, and their respiration in human dermal fibroblasts. Here, we use this protocol to investigate applicability of power law diffusion to describe mitochondrial locomotion, assessment of rates of fission and fusion in healthy and diseased cells, and differences in mitochondria locomotion in more open networks either in response to cytoskeletal destabilizers or by cell line. We found that mitochondria within fibrosarcoma cells and within fibroblast cells treated with an actin-destabilizing toxin resulted in increased net travel, increased average velocity, and increased diffusion of mitochondria when compared to control fibroblasts. Although the mitochondria within the fibrosarcoma travel further than mitochondria within their healthy counterparts, fibroblasts, the dependence on mitochondria for respiration is much lower with higher rates ofhydrogen peroxide production and was confirmed using the OROBOROS O2K. We also found that rates of fission and fusion of the mitochondria equilibrate despite significant alteration of the cytoskeleton. Rates ranged from 15% to 25%, where the highest rates were observed within the fibrosarcoma cell line. This result is interesting because the fibrosarcoma cell line does not have increased respiration metrics including when compared to fibroblast. Mitochondria travel further, faster, and have an increase in percent mitochondria splitting or joining while not dependent on the mitochondria for a majority of its energy production. This study illustrates the complex interaction between mitochondrial movement and respiration through the disruption of the cytoskeleton. Summary: We assessed the effect of cytoskeletal inhibitors and the use of a calcium ionophore as an additional stressor on mitochondrial motility and bioenergetic function in fibroblasts and fibrosarcoma cells.
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Affiliation(s)
- David H Jang
- Department of Emergency Medicine, Division of Medical Toxicology and Critical Care Medicine, Perelman School of Medicine, University of Pennsylvania, 3620 Hamilton Walk, John Morgan Building Room 12, Philadelphia, PA 19104, USA
| | - Sarah C Seeger
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Martha E Grady
- Department of Mechanical Engineering, University of Kentucky, 151 RGAN Building, Lexington, KY 40506, USA
| | - Frances S Shofer
- Department of Emergency Medicine, Division of Medical Toxicology and Critical Care Medicine, Perelman School of Medicine, University of Pennsylvania, 3620 Hamilton Walk, John Morgan Building Room 12, Philadelphia, PA 19104, USA
| | - David M Eckmann
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, 3620 Hamilton Walk, John Morgan Building Room 27B, Philadelphia, PA 19104, USA .,Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
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