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Shim G, Youn YS. Precise subcellular targeting approaches for organelle-related disorders. Adv Drug Deliv Rev 2024:115411. [PMID: 39032657 DOI: 10.1016/j.addr.2024.115411] [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: 04/23/2024] [Revised: 06/14/2024] [Accepted: 07/14/2024] [Indexed: 07/23/2024]
Abstract
Pharmacological research has expanded to the nanoscale level with advanced imaging technologies, enabling the analysis of drug distribution at the cellular organelle level. These advances in research techniques have contributed to the targeting of cellular organelles to address the fundamental causes of diseases. Beyond navigating the hurdles of reaching lesion tissues upon administration and identifying target cells within these tissues, controlling drug accumulation at the organelle level is the most refined method of disease management. This approach opens new avenues for the development of more potent therapeutic strategies by delving into the intricate roles and interplay of cellular organelles. Thus, organelle-targeted approaches help overcome the limitations of conventional therapies by precisely regulating functionally compartmentalized spaces based on their environment. This review discusses the basic concepts of organelle targeting research and proposes strategies to target diseases arising from organelle dysfunction. We also address the current challenges faced by organelle targeting and explore future research directions.
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Affiliation(s)
- Gayong Shim
- School of Systems Biomedical Science and Integrative Institute of Basic Sciences, Soongsil University, Seoul 06978, Republic of Korea
| | - Yu Seok Youn
- School of Pharmacy, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do, 16419, Republic of Korea.
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2
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Ozlu C, Messahel S, Minassian B, Kayani S. Mitochondrial encephalopathies and myopathies: Our tertiary center's experience. Eur J Paediatr Neurol 2024; 50:31-40. [PMID: 38583367 DOI: 10.1016/j.ejpn.2024.03.005] [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: 01/19/2024] [Revised: 03/12/2024] [Accepted: 03/22/2024] [Indexed: 04/09/2024]
Abstract
Mitochondrial diseases have a heterogeneous phenotype and can result from mutations in the mitochondrial or nuclear genomes, constituting a diagnostically and therapeutically challenging group of disorders. We report our center's experience with mitochondrial encephalopathies and myopathies with a cohort of 50 genetically and phenotypically diverse patients followed in the Neurology clinic over the last ten years. Seventeen patients had mitochondrial DNA mutations, presented over a wide range of ages with seizures, feeding difficulties, extraocular movements abnormalities, and had high rates of stroke-like episodes and regression. Twenty-seven patients had nuclear DNA mutations, presented early in life with feeding difficulty, failure-to-thrive, and seizures, and had high proportions of developmental delay, wheelchair dependence, spine abnormalities and dystonia. In six patients, a mutation could not be identified, but they were included for having mitochondrial disease confirmed by histopathology, enzyme analysis and clinical features. These patients had similar characteristics to patients with nuclear DNA mutations, suggesting missed underlying mutations in the nuclear genome. Management was variable among patients, but outcomes were universally poor with severe disability in all cases. Therapeutic entryways through elucidation of disease pathways and remaining unknown genes are acutely needed.
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Affiliation(s)
- Can Ozlu
- University of Texas Southwestern Medical Center ,Dallas, TX, USA; Children's Medical Center, Dallas, TX, USA
| | | | - Berge Minassian
- University of Texas Southwestern Medical Center ,Dallas, TX, USA; Children's Medical Center, Dallas, TX, USA
| | - Saima Kayani
- University of Texas Southwestern Medical Center ,Dallas, TX, USA; Children's Medical Center, Dallas, TX, USA.
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3
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Brañas Casas R, Zuppardo A, Risato G, Dinarello A, Celeghin R, Fontana C, Grelloni E, Gilea AI, Viscomi C, Rasola A, Dalla Valle L, Lodi T, Baruffini E, Facchinello N, Argenton F, Tiso N. Zebrafish polg2 knock-out recapitulates human POLG-disorders; implications for drug treatment. Cell Death Dis 2024; 15:281. [PMID: 38643274 PMCID: PMC11032366 DOI: 10.1038/s41419-024-06622-9] [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: 11/30/2023] [Revised: 03/15/2024] [Accepted: 03/18/2024] [Indexed: 04/22/2024]
Abstract
The human mitochondrial DNA polymerase gamma is a holoenzyme, involved in mitochondrial DNA (mtDNA) replication and maintenance, composed of a catalytic subunit (POLG) and a dimeric accessory subunit (POLG2) conferring processivity. Mutations in POLG or POLG2 cause POLG-related diseases in humans, leading to a subset of Mendelian-inherited mitochondrial disorders characterized by mtDNA depletion (MDD) or accumulation of multiple deletions, presenting multi-organ defects and often leading to premature death at a young age. Considering the paucity of POLG2 models, we have generated a stable zebrafish polg2 mutant line (polg2ia304) by CRISPR/Cas9 technology, carrying a 10-nucleotide deletion with frameshift mutation and premature stop codon. Zebrafish polg2 homozygous mutants present slower development and decreased viability compared to wild type siblings, dying before the juvenile stage. Mutants display a set of POLG-related phenotypes comparable to the symptoms of human patients affected by POLG-related diseases, including remarkable MDD, altered mitochondrial network and dynamics, and reduced mitochondrial respiration. Histological analyses detected morphological alterations in high-energy demanding tissues, along with a significant disorganization of skeletal muscle fibres. Consistent with the last finding, locomotor assays highlighted a decreased larval motility. Of note, treatment with the Clofilium tosylate drug, previously shown to be effective in POLG models, could partially rescue MDD in Polg2 mutant animals. Altogether, our results point at zebrafish as an effective model to study the etiopathology of human POLG-related disorders linked to POLG2, and a suitable platform to screen the efficacy of POLG-directed drugs in POLG2-associated forms.
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Affiliation(s)
| | - Alessandro Zuppardo
- Department of Biomedical Sciences, University of Padova, Padova, 35131, Italy
| | - Giovanni Risato
- Department of Biology, University of Padova, Padova, 35131, Italy
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padova, Padova, 35128, Italy
| | - Alberto Dinarello
- Department of Biology, University of Padova, Padova, 35131, Italy
- Novo Nordisk Foundation Center for Stem Cell Medicine (reNEW), University of Copenhagen, Copenhagen, 2200, Denmark
| | - Rudy Celeghin
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padova, Padova, 35128, Italy
| | - Camilla Fontana
- Department of Biology, University of Padova, Padova, 35131, Italy
- Department of Animal and Aquatic Sciences, Faculty of Agriculture, Chiang Mai University, Chiang Mai, 50200, Thailand
| | | | - Alexandru Ionut Gilea
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, 43124, Italy
| | - Carlo Viscomi
- Department of Biomedical Sciences, University of Padova, Padova, 35131, Italy
| | - Andrea Rasola
- Department of Biomedical Sciences, University of Padova, Padova, 35131, Italy
| | | | - Tiziana Lodi
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, 43124, Italy
| | - Enrico Baruffini
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, 43124, Italy
| | - Nicola Facchinello
- Neuroscience Institute, Italian Research Council (CNR), 35131, Padova, Italy.
| | | | - Natascia Tiso
- Department of Biology, University of Padova, Padova, 35131, Italy.
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4
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Scaravilli A, Tranfa M, Pontillo G, Brais B, De Michele G, La Piana R, Saccà F, Santorelli FM, Synofzik M, Brunetti A, Cocozza S. A Review of Brain and Pituitary Gland MRI Findings in Patients with Ataxia and Hypogonadism. CEREBELLUM (LONDON, ENGLAND) 2024; 23:757-774. [PMID: 37155088 DOI: 10.1007/s12311-023-01562-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/26/2023] [Indexed: 05/10/2023]
Abstract
The association of cerebellar ataxia and hypogonadism occurs in a heterogeneous group of disorders, caused by different genetic mutations often associated with a recessive inheritance. In these patients, magnetic resonance imaging (MRI) plays a pivotal role in the diagnostic workflow, with a variable involvement of the cerebellar cortex, alone or in combination with other brain structures. Neuroimaging involvement of the pituitary gland is also variable. Here, we provide an overview of the main clinical and conventional brain and pituitary gland MRI imaging findings of the most common genetic mutations associated with the clinical phenotype of ataxia and hypogonadism, with the aim of helping neuroradiologists in the identification of these disorders.
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Affiliation(s)
- Alessandra Scaravilli
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Via Pansini 5, 80131, Naples, Italy
| | - Mario Tranfa
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Via Pansini 5, 80131, Naples, Italy
| | - Giuseppe Pontillo
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Via Pansini 5, 80131, Naples, Italy
- Department of Electrical Engineering and Information Technology (DIETI), University of Naples "Federico II", Naples, Italy
| | - Bernard Brais
- Department of Neurology and Neurosurgery, Montreal Neurological Hospital and Institute, Montreal, Canada
| | - Giovanna De Michele
- Department of Neurosciences and Reproductive and Odontostomatological Sciences, University of Naples "Federico II", Naples, Italy
| | - Roberta La Piana
- Department of Neurology and Neurosurgery, Montreal Neurological Hospital and Institute, Montreal, Canada
| | - Francesco Saccà
- Department of Neurosciences and Reproductive and Odontostomatological Sciences, University of Naples "Federico II", Naples, Italy
| | | | - Matthis Synofzik
- German Center for Neurodegenerative Diseases (DZNE), Tubingen, Germany
- Division Translational Genomics of Neurodegenerative Diseases, Center for Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Otfried-Müller-Strasse 27, 72076, Tubingen, Germany
| | - Arturo Brunetti
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Via Pansini 5, 80131, Naples, Italy
| | - Sirio Cocozza
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Via Pansini 5, 80131, Naples, Italy.
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5
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Kadohisa M, Okamoto T, Yamamoto M, Uebayashi EY, Sonoda M, Ogawa E, Yokoyama A, Kawasaki H, Hiejima E, Ito S, Togawa T, Imagawa K, Murayama K, Okajima H, Hatano E. Living donor liver transplantation for myocerebrohepatopathy spectrum due to POLG mutations. Pediatr Transplant 2024; 28:e14659. [PMID: 38012111 DOI: 10.1111/petr.14659] [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: 06/06/2023] [Revised: 09/26/2023] [Accepted: 11/15/2023] [Indexed: 11/29/2023]
Abstract
BACKGROUND POLG is one of several nuclear genes associated with mitochondrial DNA maintenance defects and is a group of diseases caused by mitochondrial DNA deficiency that results in impaired adenosine triphosphate production and organ dysfunction. Myocerebrohepatopathy spectrum (MCHS) is the most severe and earliest presentation of POLG mutations, and liver transplantation (LT) for MCHS has never been reported. CASE PRESENTATION The patient was a 3-month-old boy with acute liver failure and no neurological manifestations (e.g., seizures). We performed a living donor LT using a left lateral segment graft from his father. The postoperative course was uneventful. Subsequently, a homozygous POLG mutation (c.2890C>T, p. R964C) was identified by multigene analysis of neonatal/infantile intrahepatic cholestasis. Moreover, respiratory chain complex I, II, and III enzyme activities and the ratio of mtDNA to nuclear DNA in the liver were reduced. Therefore, we considered that these clinical manifestations and examination findings met the definition for MCHS. During meticulous follow-up, the patient had shown satisfactory physical growth and mental development until the time of writing this report. CONCLUSION We presumed that the absence of remarkable neurologic manifestations prior to LT in patients with MCHS is a good indication for LT and contributes to a better prognosis in the present case.
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Affiliation(s)
- Masashi Kadohisa
- Department of Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Pediatric Surgery, Kyoto University Hospital, Kyoto, Japan
| | - Tatsuya Okamoto
- Department of Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Pediatric Surgery, Kyoto University Hospital, Kyoto, Japan
| | - Miki Yamamoto
- Department of Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Pediatric Surgery, Kyoto University Hospital, Kyoto, Japan
| | - Elena Yukie Uebayashi
- Department of Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Pediatric Surgery, Kyoto University Hospital, Kyoto, Japan
| | - Mari Sonoda
- Department of Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Pediatric Surgery, Kyoto University Hospital, Kyoto, Japan
| | - Eri Ogawa
- Department of Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Pediatric Surgery, Kyoto University Hospital, Kyoto, Japan
| | - Atsushi Yokoyama
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Hidenori Kawasaki
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Eitaro Hiejima
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Shogo Ito
- Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Takao Togawa
- Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Kazuo Imagawa
- Department of Child Health, Institute of Medicine, University of Tsukuba, Ibaraki, Japan
| | - Kei Murayama
- Department of Metabolism, Center for Medical Genetics, Chiba Children's Hospital, Chiba, Japan
| | - Hideaki Okajima
- Department of Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Pediatric Surgery, Kanazawa Medical University, Kanazawa, Japan
| | - Etsuro Hatano
- Department of Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Pediatric Surgery, Kyoto University Hospital, Kyoto, Japan
- Department of Hepato-Biliary-Pancreatic Surgery and Transplantation, Kyoto University Hospital, Kyoto, Japan
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6
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Hong Y, Zhang Z, Yangzom T, Chen A, Lundberg BC, Fang EF, Siller R, Sullivan GJ, Zeman J, Tzoulis C, Bindoff LA, Liang KX. The NAD + Precursor Nicotinamide Riboside Rescues Mitochondrial Defects and Neuronal Loss in iPSC derived Cortical Organoid of Alpers' Disease. Int J Biol Sci 2024; 20:1194-1217. [PMID: 38385069 PMCID: PMC10878163 DOI: 10.7150/ijbs.91624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Accepted: 01/11/2024] [Indexed: 02/23/2024] Open
Abstract
Alpers' syndrome is an early-onset neurodegenerative disorder usually caused by biallelic pathogenic variants in the gene encoding the catalytic subunit of polymerase-gamma (POLG), which is essential for mitochondrial DNA (mtDNA) replication. The disease is progressive, incurable, and inevitably it leads to death from drug-resistant status epilepticus. The neurological features of Alpers' syndrome are intractable epilepsy and developmental regression, with no effective treatment; the underlying mechanisms are still elusive, partially due to lack of good experimental models. Here, we generated the patient derived induced pluripotent stem cells (iPSCs) from one Alpers' patient carrying the compound heterozygous mutations of A467T (c.1399G>A) and P589L (c.1766C>T), and further differentiated them into cortical organoids and neural stem cells (NSCs) for mechanistic studies of neural dysfunction in Alpers' syndrome. Patient cortical organoids exhibited a phenotype that faithfully replicated the molecular changes found in patient postmortem brain tissue, as evidenced by cortical neuronal loss and depletion of mtDNA and complex I (CI). Patient NSCs showed mitochondrial dysfunction leading to ROS overproduction and downregulation of the NADH pathway. More importantly, the NAD+ precursor nicotinamide riboside (NR) significantly ameliorated mitochondrial defects in patient brain organoids. Our findings demonstrate that the iPSC model and brain organoids are good in vitro models of Alpers' disease; this first-in-its-kind stem cell platform for Alpers' syndrome enables therapeutic exploration and has identified NR as a viable drug candidate for Alpers' disease and, potentially, other mitochondrial diseases with similar causes.
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Affiliation(s)
- Yu Hong
- Department of Clinical Medicine (K1), University of Bergen, Bergen, Norway
- Neuro-SysMed, Center of Excellence for Clinical Research in Neurological Diseases, Haukeland University Hospital, Bergen, Norway
- Department of Neurology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Zhuoyuan Zhang
- Department of Clinical Medicine (K1), University of Bergen, Bergen, Norway
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China School of Stomatology, Sichuan University, Chengdu, China
- Department of Head and Neck Cancer Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Tsering Yangzom
- Department of Clinical Medicine (K1), University of Bergen, Bergen, Norway
- Neuro-SysMed, Center of Excellence for Clinical Research in Neurological Diseases, Haukeland University Hospital, Bergen, Norway
- Centre for International Health, University of Bergen, Bergen, Norway
| | - Anbin Chen
- Department of Clinical Medicine (K1), University of Bergen, Bergen, Norway
- Neuro-SysMed, Center of Excellence for Clinical Research in Neurological Diseases, Haukeland University Hospital, Bergen, Norway
| | - Bjørn Christian Lundberg
- Department of Clinical Medicine (K1), University of Bergen, Bergen, Norway
- Neuro-SysMed, Center of Excellence for Clinical Research in Neurological Diseases, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Molecular Biology, Akershus University Hospital, University of Oslo, Oslo, Norway
| | - Evandro Fei Fang
- Department of Clinical Molecular Biology, Akershus University Hospital, University of Oslo, Oslo, Norway
- The Norwegian Centre on Healthy Ageing, Oslo, Norway
| | - Richard Siller
- Norwegian Center for Stem Cell Research, University of Oslo, 0317, Oslo, Norway
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317, Oslo, Norway
| | - Gareth John Sullivan
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317, Oslo, Norway
- Institute of Immunology, Oslo University Hospital, Oslo, Norway
- Department of Pediatric Research, Oslo University Hospital, Oslo, Norway
| | - Jiri Zeman
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Charalampos Tzoulis
- Department of Clinical Medicine (K1), University of Bergen, Bergen, Norway
- Neuro-SysMed, Center of Excellence for Clinical Research in Neurological Diseases, Haukeland University Hospital, Bergen, Norway
- KG Jebsen Center for Parkinson's disease, University of Bergen, Bergen, Norway
| | - Laurence A. Bindoff
- Department of Clinical Medicine (K1), 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 (K1), 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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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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Harju T, Hurme-Niiranen A, Suo-Palosaari M, Nygaard Nielsen S, Hinttala R, Schmiegelow K, Uusimaa J, Harila A, Niinimäki R. DNA polymerase gamma variants and hepatotoxicity during maintenance therapy of childhood acute lymphoblastic leukemia: is there a causal relationship? THE PHARMACOGENOMICS JOURNAL 2023; 23:105-111. [PMID: 37138020 PMCID: PMC10506908 DOI: 10.1038/s41397-023-00303-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 03/03/2023] [Accepted: 03/13/2023] [Indexed: 05/05/2023]
Abstract
Hepatotoxicity is a frequent complication during maintenance therapy of acute lymphoblastic leukemia (ALL) with 6-mercaptopurine and methotrexate. Elevated levels of methylated 6-mercaptopurine metabolites (MeMP) are associated with hepatotoxicity. However, not all mechanisms are known that lead to liver failure in patients with ALL. Variants in the POLG gene, which encodes the catalytic subunit of mitochondrial DNA polymerase gamma (POLG1), have been related to drug-induced hepatotoxicity, for example, by sodium valproate. The association of common POLG variants with hepatotoxicity during maintenance therapy was studied in 34 patients with childhood ALL. Of the screened POLG variants, four different variants were detected in 12 patients. One patient developed severe hepatotoxicity without elevated MeMP levels and harbored a heterozygous POLG p.G517V variant, which was not found in the other patients.
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Affiliation(s)
- Tekla Harju
- Research Unit of Clinical Medicine, University of Oulu, Oulu, Finland.
- Department of Children and Adolescents, Oulu University Hospital, Oulu, Finland.
| | - Anri Hurme-Niiranen
- Research Unit of Clinical Medicine, University of Oulu, Oulu, Finland
- Medical Research Center, University of Oulu and Oulu University Hospital, Oulu, Finland
| | - Maria Suo-Palosaari
- Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland
- Research Unit of Health Sciences and Technology, Oulu University Hospital and University of Oulu, Oulu, Finland
| | - Stine Nygaard Nielsen
- Department of Pediatrics and Adolescent Medicine, Rigshospitalet, Copenhagen University Hospital, and Institute of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Reetta Hinttala
- Research Unit of Clinical Medicine, University of Oulu, Oulu, Finland
- Medical Research Center, University of Oulu and Oulu University Hospital, Oulu, Finland
- Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Kjeld Schmiegelow
- Pediatric Oncology Laboratory, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Johanna Uusimaa
- Research Unit of Clinical Medicine, University of Oulu, Oulu, Finland
- Department of Children and Adolescents, Oulu University Hospital, Oulu, Finland
- Medical Research Center, University of Oulu and Oulu University Hospital, Oulu, Finland
| | - Arja Harila
- Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden
| | - Riitta Niinimäki
- Research Unit of Clinical Medicine, University of Oulu, Oulu, Finland
- Department of Children and Adolescents, Oulu University Hospital, Oulu, Finland
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9
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Tyler SE, Tyler LD. Pathways to healing: Plants with therapeutic potential for neurodegenerative diseases. IBRO Neurosci Rep 2023; 14:210-234. [PMID: 36880056 PMCID: PMC9984566 DOI: 10.1016/j.ibneur.2023.01.006] [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: 09/24/2022] [Accepted: 01/25/2023] [Indexed: 02/12/2023] Open
Abstract
Some of the greatest challenges in medicine are the neurodegenerative diseases (NDs), which remain without a cure and mostly progress to death. A companion study employed a toolkit methodology to document 2001 plant species with ethnomedicinal uses for alleviating pathologies relevant to NDs, focusing on its relevance to Alzheimer's disease (AD). This study aimed to find plants with therapeutic bioactivities for a range of NDs. 1339 of the 2001 plant species were found to have a bioactivity from the literature of therapeutic relevance to NDs such as Parkinson's disease, Huntington's disease, AD, motor neurone diseases, multiple sclerosis, prion diseases, Neimann-Pick disease, glaucoma, Friedreich's ataxia and Batten disease. 43 types of bioactivities were found, such as reducing protein misfolding, neuroinflammation, oxidative stress and cell death, and promoting neurogenesis, mitochondrial biogenesis, autophagy, longevity, and anti-microbial activity. Ethno-led plant selection was more effective than random selection of plant species. Our findings indicate that ethnomedicinal plants provide a large resource of ND therapeutic potential. The extensive range of bioactivities validate the usefulness of the toolkit methodology in the mining of this data. We found that a number of the documented plants are able to modulate molecular mechanisms underlying various key ND pathologies, revealing a promising and even profound capacity to halt and reverse the processes of neurodegeneration.
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Key Words
- A-H, Alpers-Huttenlocher syndrome
- AD, Alzheimer’s disease
- ALS, Amyotrophic lateral sclerosis
- BBB, blood-brain barrier
- C. elegans,, Caenorhabditis elegans
- CJD, Creutzfeldt-Jakob disease
- CMT, Charcot–Marie–Tooth disease
- CS, Cockayne syndrome
- Ech A, Echinochrome A
- FDA, Food and Drug Administration
- FRDA, Friedreich’s ataxia
- FTD, Frontotemporal dementia
- HD, Huntington’s disease
- Hsp, Heat shock protein
- LSD, Lysosomal storage diseases
- MS, Multiple sclerosis
- MSA, Multiple system atrophy
- MSP, Multisystem proteinopathy
- Medicinal plant
- ND, neurodegenerative disease
- NPC, Neimann-Pick disease type C
- NSC, neural stem cells
- Neuro-inflammation
- Neurodegeneration
- Neurogenesis
- PC, pharmacological chaperone
- PD, Parkinson’s disease
- Protein misfolding
- SMA, Spinal muscular atrophy
- VD, Vascular dementia
- prion dis, prion diseases
- α-syn, alpha-synuclein
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Affiliation(s)
- Sheena E.B. Tyler
- John Ray Research Field Station, Cheshire, United Kingdom
- Corresponding author.
| | - Luke D.K. Tyler
- School of Natural Sciences, Bangor University, Gwynedd, United Kingdom
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10
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Nerve-Wracking Eye Puzzle: A Rare Case of Alpers-Huttenlocher Syndrome. J Neuroophthalmol 2023; 43:e6-e8. [PMID: 34812764 DOI: 10.1097/wno.0000000000001341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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11
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Naren P, Cholkar A, Kamble S, Khan SS, Srivastava S, Madan J, Mehra N, Tiwari V, Singh SB, Khatri DK. Pathological and Therapeutic Advances in Parkinson's Disease: Mitochondria in the Interplay. J Alzheimers Dis 2023; 94:S399-S428. [PMID: 36093711 PMCID: PMC10473111 DOI: 10.3233/jad-220682] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2022] [Indexed: 11/15/2022]
Abstract
Parkinson's disease (PD) is the second most common neurodegenerative illness majorly affecting the population between the ages of 55 to 65 years. Progressive dopaminergic neuronal loss and the collective assemblage of misfolded alpha-synuclein in the substantia nigra, remain notable neuro-pathological hallmarks of the disease. Multitudes of mechanistic pathways have been proposed in attempts to unravel the pathogenesis of PD but still, it remains elusive. The convergence of PD pathology is found in organelle dysfunction where mitochondria remain a major contributor. Mitochondrial processes like bioenergetics, mitochondrial dynamics, and mitophagy are under strict regulation by the mitochondrial genome and nuclear genome. These processes aggravate neurodegenerative activities upon alteration through neuroinflammation, oxidative damage, apoptosis, and proteostatic stress. Therefore, the mitochondria have grabbed a central position in the patho-mechanistic exploration of neurodegenerative diseases like PD. The management of PD remains a challenge to physicians to date, due to the variable therapeutic response of patients and the limitation of conventional chemical agents which only offer symptomatic relief with minimal to no disease-modifying effect. This review describes the patho-mechanistic pathways involved in PD not only limited to protein dyshomeostasis and oxidative stress, but explicit attention has been drawn to exploring mechanisms like organelle dysfunction, primarily mitochondria and mitochondrial genome influence, while delineating the newer exploratory targets such as GBA1, GLP, LRRK2, and miRNAs and therapeutic agents targeting them.
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Affiliation(s)
- Padmashri Naren
- Department of Pharmacology & Toxicology, National Institute of Pharmaceutical Education and Research, Hyderabad, Telangana, India
| | - Anjali Cholkar
- Department of Pharmacology & Toxicology, National Institute of Pharmaceutical Education and Research, Hyderabad, Telangana, India
| | - Suchita Kamble
- Department of Pharmacology & Toxicology, National Institute of Pharmaceutical Education and Research, Hyderabad, Telangana, India
| | - Sabiya Samim Khan
- Department of Pharmacology & Toxicology, National Institute of Pharmaceutical Education and Research, Hyderabad, Telangana, India
| | - Saurabh Srivastava
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER)-Hyderabad, Telangana, India
| | - Jitender Madan
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER)-Hyderabad, Telangana, India
| | - Neelesh Mehra
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER)-Hyderabad, Telangana, India
| | - Vinod Tiwari
- Department of Pharmaceutical Engineering & Technology, Indian Institute of Technology (B.H.U.) Varanasi (U.P.), India
| | - Shashi Bala Singh
- Department of Pharmacology & Toxicology, National Institute of Pharmaceutical Education and Research, Hyderabad, Telangana, India
| | - Dharmendra Kumar Khatri
- Department of Pharmacology & Toxicology, National Institute of Pharmaceutical Education and Research, Hyderabad, Telangana, India
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12
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ÖZDEMİR M, HAMİTOĞLU Ş, ÖZLÜ F, YAPICIOĞLU H, GÜL MERT G, SATAR M. The first living newborn case with 7706G˃A missense mutation: Alpers-Huttenlocher syndrome. CUKUROVA MEDICAL JOURNAL 2022. [DOI: 10.17826/cumj.1170135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Alpers-Huttenlocher syndrome (AHS) is an uncommon autosomal recessive mitochondrial DNA depletion disease. The classic clinical triad of progressive developmental regression, liver degeneration, and seizures helps define the disorder, but a wide range of clinical expressions occur. The most common mutations in childhood have been identified in the cytochrome c oxidase Ⅰ and Ⅳ genes. The 7706G˃A missense mutation in the Cox Ⅱ gene was previously reported in one case after postmortem histological study. Consequently, our patient is the first patient diagnosed with AHS with a 7706G˃A missense mutation in the Cox Ⅱ gene while alive. We proposed that 7706G˃A missense mutation is rare and should be more lethal than other mutations that cause Alpers-Huttenlocher syndrome.
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Affiliation(s)
| | | | - Ferda ÖZLÜ
- Cukurova University Medical Faculty, Neonatology Department
| | | | - Gülen GÜL MERT
- Cukurova University Medical Faculty, Division of Pediatric Neurology
| | - Mehmet SATAR
- Cukurova University Medical Faculty, Neonatology Department
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13
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Pedersen ZO, Holm-Yildiz S, Dysgaard T. Nutritional Interventions for Patients with Mitochondrial POLG-Related Diseases: A Systematic Review on Efficacy and Safety. Int J Mol Sci 2022; 23:ijms231810658. [PMID: 36142570 PMCID: PMC9502393 DOI: 10.3390/ijms231810658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 09/08/2022] [Accepted: 09/09/2022] [Indexed: 12/03/2022] Open
Abstract
Ketogenic diet is recommended as a treatment to reduce seizure frequency in patients with intractable epilepsy. The evidence and safety results are sparse for diet interventions in patients with pathogenic polymerase gamma (POLG) variants and intractable epilepsy. The aim of this systematic review is to summarize the efficacy of diet treatment on seizure frequency, clinical symptoms, and potential deleterious effect of liver involvement in patients with mitochondrial diseases caused by pathogenic POLG variants. Literature was searched in PubMed, Embase; and Cochrane in April 2022; no filter restrictions were imposed. The reference lists of retrieved studies were checked for additional literature. Eligibility criteria included verified pathogenic POLG variant and diet treatment. Overall, 880 studies were identified, providing eight case-reports representing nine patients eligible for inclusion. In eight of nine cases, clinical symptoms were improved; six out of nine cases reported improvements in seizure frequency. However, increasing levels of liver enzymes after initiating ketogenic diet were found in four of the nine cases, with one case revealing decreased levels of liver enzymes after initiating long-chain triglyceride restriction. Viewed together, the studies imply that ketogenic diet can have a positive impact on seizure frequency, but may induce progression of liver impairment in patients with pathogenic POLG variants.
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14
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A new pathogenic POLG variant. Mol Genet Metab Rep 2022; 32:100890. [PMID: 35860755 PMCID: PMC9289853 DOI: 10.1016/j.ymgmr.2022.100890] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 06/22/2022] [Accepted: 06/23/2022] [Indexed: 11/20/2022] Open
Abstract
POLG gene mutations are the most common causes of inherited mitochondrial disorders. The enzyme produced by this gene is responsible for the replication and repair of mitochondrial DNA. To date, around 300 pathogenic variants have been described in this gene. The resulting clinical outcomes of POLG mutations are widely variable in both phenotype and severity. There is considerable overlap in the phenotype of the so-called POLG syndromes with no clear genotype-phenotype correlation. Here we describe a newly discovered pathogenic variant in the POLG gene in a 7-year-old male that died of uncontrollable refractory status epilepticus. Genetic epilepsy panel sequencing identified two variants in the POLG gene, the common p.A467T pathological mutation and a novel p.S809R POLG variant found in trans with the p.A467T POLG that accompanied a severely reduced mitochondrial DNA level in the patient's tissues.
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15
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Harrar D, Mondok L, Adams S, Farias-Moeller R. Zebras Seize the Day. Crit Care Clin 2022; 38:349-373. [DOI: 10.1016/j.ccc.2021.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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16
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Abstract
The presence of unprovoked, recurrent seizures, particularly when drug resistant and associated with cognitive and behavioral deficits, warrants investigation for an underlying genetic cause. This article provides an overview of the major classes of genes associated with epilepsy phenotypes divided into functional categories along with the recommended work-up and therapeutic considerations. Gene discovery in epilepsy supports counseling and anticipatory guidance but also opens the door for precision medicine guiding therapy with a focus on those with disease-modifying effects.
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Affiliation(s)
- Luis A Martinez
- Department of Pediatrics, Section of Pediatric Neurology and Developmental Neuroscience, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Drive, Houston, TX 77030, USA
| | - Yi-Chen Lai
- Department of Pediatrics, Section of Pediatric Critical Care Medicine, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Drive, Houston, TX 77030, USA
| | - J Lloyd Holder
- Department of Pediatrics, Section of Pediatric Neurology and Developmental Neuroscience, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Drive, Houston, TX 77030, USA
| | - Anne E Anderson
- Department of Pediatrics, Section of Pediatric Neurology and Developmental Neuroscience, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Drive, Houston, TX 77030, USA.
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17
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Senthilvelan S, Sekar SS, Kesavadas C, Thomas B. Neuromitochondrial Disorders : Genomic Basis and an Algorithmic Approach to Imaging Diagnostics. Clin Neuroradiol 2021; 31:559-574. [PMID: 34106285 DOI: 10.1007/s00062-021-01030-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 04/28/2021] [Indexed: 10/21/2022]
Abstract
Mitochondrial disorders have been an enigma for a long time due to the varied clinical presentations. Although a genetic confirmation will be mandatory most of the time, half the number of Leigh syndrome would be negative for genetic mutations. There are a growing number of mutations in clinical practice, which escape detection on routine clinical exome sequencing. Imaging would render help in pointing towards a mitochondrial disorder. There are a few case reports which brief about specific mitochondrial mutations and their specific imaging appearance. This article tries to provide a comprehensive review on the imaging-genomic correlation of mitochondrial disorders with an objective of performing a specific genetic testing to arrive at an accurate diagnosis.
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Affiliation(s)
- Santhakumar Senthilvelan
- Department of IS&IR, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Kerala, Trivandrum, India
| | - Sabarish S Sekar
- Department of IS&IR, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Kerala, Trivandrum, India
| | - Chandrasekharan Kesavadas
- Department of IS&IR, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Kerala, Trivandrum, India
| | - Bejoy Thomas
- Department of IS&IR, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Kerala, Trivandrum, India.
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18
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Mitochondrial Syndromes Revisited. J Clin Med 2021; 10:jcm10061249. [PMID: 33802970 PMCID: PMC8002645 DOI: 10.3390/jcm10061249] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 03/01/2021] [Accepted: 03/12/2021] [Indexed: 12/19/2022] Open
Abstract
In the last ten years, the knowledge of the genetic basis of mitochondrial diseases has significantly advanced. However, the vast phenotypic variability linked to mitochondrial disorders and the peculiar characteristics of their genetics make mitochondrial disorders a complex group of disorders. Although specific genetic alterations have been associated with some syndromic presentations, the genotype–phenotype relationship in mitochondrial disorders is complex (a single mutation can cause several clinical syndromes, while different genetic alterations can cause similar phenotypes). This review will revisit the most common syndromic pictures of mitochondrial disorders, from a clinical rather than a molecular perspective. We believe that the new phenotype definitions implemented by recent large multicenter studies, and revised here, may contribute to a more homogeneous patient categorization, which will be useful in future studies on natural history and clinical trials.
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19
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Fang Y, Yu J, Lou J, Peng K, Zhao H, Chen J. Clinical and Genetic Spectra of Inherited Liver Disease in Children in China. Front Pediatr 2021; 9:631620. [PMID: 33763395 PMCID: PMC7982861 DOI: 10.3389/fped.2021.631620] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 01/18/2021] [Indexed: 11/18/2022] Open
Abstract
Background: Children presenting with chronic liver disease or acute liver failure often have an underlying genetic disorder. The aim of this study was to analyze the clinical and genetic spectra of inherited liver disease in children in a tertiary hospital. Methods: A total of 172 patients were classified into three groups according to their clinical presentation: cholestasis (Group A), liver enzyme elevation (Group B), and hepato/splenomegaly (Group C). Next-generation sequencing (NGS) was performed on all patients recruited in this study. The genotypic and phenotypic spectra of disease in these patients were reviewed. Results: The median age at enrollment of the 172 patients was 12.0 months (IQR: 4.9, 42.5 months), with 52.3% males and 47.7% females. The overall diagnostic rate was 55.8% (96/172) in this group. The diagnostic rates of whole-exome sequencing (WES) and targeted gene panel sequencing (TGPS) were 47.2% and 62.0%, respectively (no significant difference, p = 0.054). We identified 25 genes related to different phenotypes, including 46 novel disease-related pathogenic mutations. The diagnostic rates in the three groups were 46.0% (29/63), 48.6% (34/70), and 84.6% (33/39). ATP7B, SLC25A13, and G6PC were the top three genes related to monogenic liver disease in this study. Conclusion: WES and TGPS show similar diagnostic rates in the diagnosis of monogenic liver disease. NGS has an important role in the diagnosis of monogenetic liver disease and can provide more precise medical treatment and predict the prognosis of these diseases.
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Affiliation(s)
- Youhong Fang
- National Clinical Research Center for Child Health, Department of Gastroenterology, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jindan Yu
- National Clinical Research Center for Child Health, Department of Gastroenterology, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jingan Lou
- National Clinical Research Center for Child Health, Department of Gastroenterology, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Kerong Peng
- National Clinical Research Center for Child Health, Department of Gastroenterology, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Hong Zhao
- National Clinical Research Center for Child Health, Department of Gastroenterology, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jie Chen
- National Clinical Research Center for Child Health, Department of Gastroenterology, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
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20
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Saneto RP. Mitochondrial diseases: expanding the diagnosis in the era of genetic testing. JOURNAL OF TRANSLATIONAL GENETICS AND GENOMICS 2020; 4:384-428. [PMID: 33426505 PMCID: PMC7791531 DOI: 10.20517/jtgg.2020.40] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mitochondrial diseases are clinically and genetically heterogeneous. These diseases were initially described a little over three decades ago. Limited diagnostic tools created disease descriptions based on clinical, biochemical analytes, neuroimaging, and muscle biopsy findings. This diagnostic mechanism continued to evolve detection of inherited oxidative phosphorylation disorders and expanded discovery of mitochondrial physiology over the next two decades. Limited genetic testing hampered the definitive diagnostic identification and breadth of diseases. Over the last decade, the development and incorporation of massive parallel sequencing has identified approximately 300 genes involved in mitochondrial disease. Gene testing has enlarged our understanding of how genetic defects lead to cellular dysfunction and disease. These findings have expanded the understanding of how mechanisms of mitochondrial physiology can induce dysfunction and disease, but the complete collection of disease-causing gene variants remains incomplete. This article reviews the developments in disease gene discovery and the incorporation of gene findings with mitochondrial physiology. This understanding is critical to the development of targeted therapies.
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Affiliation(s)
- Russell P. Saneto
- Center for Integrative Brain Research, Neuroscience Institute, Seattle, WA 98101, USA
- Department of Neurology/Division of Pediatric Neurology, Seattle Children’s Hospital/University of Washington, Seattle, WA 98105, USA
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21
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Sanderson KG, Millar E, Tumber A, Klatt R, Sondheimer N, Vincent A. Rod bipolar cell dysfunction in POLG retinopathy. Doc Ophthalmol 2020; 142:111-118. [PMID: 32567010 DOI: 10.1007/s10633-020-09777-w] [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: 04/21/2020] [Accepted: 06/09/2020] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To report the clinical and novel electrophysiological features in a child with POLG-related sensory ataxic neuropathy, dysarthria and ophthalmoparesis (SANDO). METHODS The proband, a male child of Indian descent, underwent serial systemic and ophthalmological evaluations from birth until 14 years of age. Eye examinations included visual acuity and extraocular movement assessments, fundus photography, spectral domain optical coherence tomography and full-field electroretinography (ERG). Detailed genetic testing was also performed. RESULTS The child carried a homozygous mutation in POLG (c.911T > G/p.Leu304Arg) and manifested systemic features such as seizures, headaches, areflexia, hypotonia, myopathy and vomiting. The child's distance visual acuity was 0.50 and 0.40 LogMAR in the right and left eyes, respectively. Bilateral ophthalmoplegia and ptosis were observed at 5 years of age. The dark-adapted (DA) ERG responses to 2.29 cd s m-2 and 7.6 cd s m-2 stimuli showed a markedly reduced b/a ratio; an electronegative configuration was noted to a DA 7.6 ERG. CONCLUSION This is the first documented case of an electronegative ERG in a POLG-related disorder consistent with generalized rod ON-bipolar dysfunction. The rest of the proband's systemic and ophthalmological features were consistent with SANDO but some features overlapped with other POLG-related disorders such as Alpers-Huttenlocher syndrome and autosomal dominant progressive external ophthalmoplegia demonstrating the wide phenotypic overlap expected due to POLG mutations.
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Affiliation(s)
- Kit Green Sanderson
- Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Canada
| | - Eoghan Millar
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - Anupreet Tumber
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - Regan Klatt
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - Neal Sondheimer
- Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Canada.,Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto, Canada
| | - Ajoy Vincent
- Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Canada. .,Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, Canada.
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22
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Granat L, Hunt RJ, Bateman JM. Mitochondrial retrograde signalling in neurological disease. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190415. [PMID: 32362256 DOI: 10.1098/rstb.2019.0415] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Neuronal mitochondrial dysfunction causes primary mitochondrial diseases and likely contributes to neurodegenerative diseases including Parkinson's and Alzheimer's disease. Mitochondrial dysfunction has also been documented in neurodevelopmental disorders such as tuberous sclerosis complex and autism spectrum disorder. Only symptomatic treatments exist for neurodevelopmental disorders, while neurodegenerative diseases are largely untreatable. Altered mitochondrial function activates mitochondrial retrograde signalling pathways, which enable signalling to the nucleus to reprogramme nuclear gene expression. In this review, we discuss the role of mitochondrial retrograde signalling in neurological diseases. We summarize how mitochondrial dysfunction contributes to neurodegenerative disease and neurodevelopmental disorders. Mitochondrial signalling mechanisms that have relevance to neurological disease are discussed. We then describe studies documenting retrograde signalling pathways in neurons and glia, and in animal models of neuronal mitochondrial dysfunction and neurological disease. Finally, we suggest how specific retrograde signalling pathways can be targeted to develop novel treatments for neurological diseases. This article is part of the theme issue 'Retrograde signalling from endosymbiotic organelles'.
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Affiliation(s)
- Lucy Granat
- Maurice Wohl Clinical Neuroscience Institute, King's College London, 125 Coldharbour Lane, London SE5 9NU, UK
| | - Rachel J Hunt
- Maurice Wohl Clinical Neuroscience Institute, King's College London, 125 Coldharbour Lane, London SE5 9NU, UK
| | - Joseph M Bateman
- Maurice Wohl Clinical Neuroscience Institute, King's College London, 125 Coldharbour Lane, London SE5 9NU, UK
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23
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Dard L, Blanchard W, Hubert C, Lacombe D, Rossignol R. Mitochondrial functions and rare diseases. Mol Aspects Med 2020; 71:100842. [PMID: 32029308 DOI: 10.1016/j.mam.2019.100842] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 12/26/2019] [Accepted: 12/27/2019] [Indexed: 12/19/2022]
Abstract
Mitochondria are dynamic cellular organelles responsible for a large variety of biochemical processes as energy transduction, REDOX signaling, the biosynthesis of hormones and vitamins, inflammation or cell death execution. Cell biology studies established that 1158 human genes encode proteins localized to mitochondria, as registered in MITOCARTA. Clinical studies showed that a large number of these mitochondrial proteins can be altered in expression and function through genetic, epigenetic or biochemical mechanisms including the interaction with environmental toxics or iatrogenic medicine. As a result, pathogenic mitochondrial genetic and functional defects participate to the onset and the progression of a growing number of rare diseases. In this review we provide an exhaustive survey of the biochemical, genetic and clinical studies that demonstrated the implication of mitochondrial dysfunction in human rare diseases. We discuss the striking diversity of the symptoms caused by mitochondrial dysfunction and the strategies proposed for mitochondrial therapy, including a survey of ongoing clinical trials.
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Affiliation(s)
- L Dard
- Bordeaux University, 33000, Bordeaux, France; INSERM U1211, 33000, Bordeaux, France; CELLOMET, CGFB-146 Rue Léo Saignat, Bordeaux, France
| | - W Blanchard
- Bordeaux University, 33000, Bordeaux, France; INSERM U1211, 33000, Bordeaux, France; CELLOMET, CGFB-146 Rue Léo Saignat, Bordeaux, France
| | - C Hubert
- Bordeaux University, 33000, Bordeaux, France; INSERM U1211, 33000, Bordeaux, France
| | - D Lacombe
- Bordeaux University, 33000, Bordeaux, France; INSERM U1211, 33000, Bordeaux, France; CHU de Bordeaux, Service de Génétique Médicale, F-33076, Bordeaux, France
| | - R Rossignol
- Bordeaux University, 33000, Bordeaux, France; INSERM U1211, 33000, Bordeaux, France; CELLOMET, CGFB-146 Rue Léo Saignat, Bordeaux, France.
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24
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Lim A, Thomas RH. The mitochondrial epilepsies. Eur J Paediatr Neurol 2020; 24:47-52. [PMID: 31973983 DOI: 10.1016/j.ejpn.2019.12.021] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 12/17/2019] [Accepted: 12/18/2019] [Indexed: 01/19/2023]
Abstract
Mitochondria are vital organelles within cells that undertake many important metabolic roles, the most significant of which is to generate energy to support organ function. Dysfunction of the mitochondrion can lead to a wide range of clinical features, predominantly affecting organs with a high metabolic demand such as the brain. One of the main neurological manifestations of mitochondrial disease is metabolic epilepsies. These epileptic seizures are more frequently of posterior quadrant and occipital lobe onset, more likely to present with non-convulsive status epilepticus which may last months and be more resistant to treatment from the onset. The onset of can be of any age. Childhood onset epilepsy is a major phenotypic feature in mitochondrial disorders such as Alpers-Huttenlocher syndrome, pyruvate dehydrogenase complex deficiencies, and Leigh syndrome. Meanwhile, adults with classical mitochondrial disease syndrome such as MELAS, MERFF or POLG-related disorders could present with either focal or generalised seizures. There are no specific curative treatments for mitochondrial epilepsy. Generally, the epileptic seizures should be managed by specialist neurologist with appropriate use of anticonvulsants. As a general rule, especially in disorders associated with mutation in POLG, sodium valproate is best avoided because hepato-toxicity can be fulminant and fatal.
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Affiliation(s)
- Albert Lim
- Department of Paediatrics, Great Northern Children's Hospital, Queen Victoria Rd, Newcastle-Upon-Tyne, NE1 4LP, United Kingdom; Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle-Upon-Tyne, NE2 4HH, United Kingdom
| | - Rhys H Thomas
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle-Upon-Tyne, NE2 4HH, United Kingdom; Department of Neurology, Royal Victoria Infirmary, Queen Victoria Rd, Newcastle-Upon-Tyne, NE1 4LP, United Kingdom; Institute of Neuroscience, Henry Wellcome Building, Framlington Place, Newcastle University, Newcastle-Upon-Tyne, NE2 4HH, United Kingdom.
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25
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Pauly MG, Tunc S, Bäumer T, Gillessen-Kaesbach G, Münchau A. "Twitching" and Stiffness in POLG1 Mutation Carriers: Red Flag or Red Herring? Mov Disord Clin Pract 2019; 7:91-93. [PMID: 31970219 DOI: 10.1002/mdc3.12860] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 10/04/2019] [Accepted: 10/16/2019] [Indexed: 11/11/2022] Open
Affiliation(s)
- Martje G Pauly
- Institute of Neurogenetics University of Lübeck Lübeck Germany
| | - Sinem Tunc
- Institute of Neurogenetics University of Lübeck Lübeck Germany.,Department of Neurology University of Lübeck Lübeck Germany
| | - Tobias Bäumer
- Institute of Neurogenetics University of Lübeck Lübeck Germany
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26
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Piekutowska-Abramczuk D, Kaliszewska M, Sułek A, Jurkowska N, Ołtarzewski M, Jabłońska E, Trubicka J, Głowacka A, Ciara E, Kowalski P, Langiewicz-Wojciechowska K, Tesarova M, Zeman J, Kierdaszuk B, Kuczyński D, Chmielewski D, Szymańska E, Bakuła A, Łusakowska A, Lipowska M, Brodacki B, Pera J, Dorobek M, Rydzanicz M, Płoski R, Chrzanowska KH, Bartnik E, Placha G, Kamińska A, Kostera-Pruszczyk A, Krajewska-Walasek M, Tońska K, Pronicka E. The frequency of mitochondrial polymerase gamma related disorders in a large Polish population cohort. Mitochondrion 2019; 47:179-187. [DOI: 10.1016/j.mito.2018.11.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 10/02/2018] [Accepted: 11/02/2018] [Indexed: 02/06/2023]
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27
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Amyloid Beta and Phosphorylated Tau-Induced Defective Autophagy and Mitophagy in Alzheimer's Disease. Cells 2019; 8:cells8050488. [PMID: 31121890 PMCID: PMC6562604 DOI: 10.3390/cells8050488] [Citation(s) in RCA: 266] [Impact Index Per Article: 53.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Revised: 05/10/2019] [Accepted: 05/21/2019] [Indexed: 12/22/2022] Open
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disease characterized by memory loss and multiple cognitive impairments. Several decades of intense research have revealed that multiple cellular changes are implicated in the development and progression of AD, including mitochondrial damage, synaptic dysfunction, amyloid beta (Aβ) formation and accumulation, hyperphosphorylated tau (P-Tau) formation and accumulation, deregulated microRNAs, synaptic damage, and neuronal loss in patients with AD. Among these, mitochondrial dysfunction and synaptic damage are early events in the disease process. Recent research also revealed that Aβ and P-Tau-induced defective autophagy and mitophagy are prominent events in AD pathogenesis. Age-dependent increased levels of Aβ and P-Tau reduced levels of several autophagy and mitophagy proteins. In addition, abnormal interactions between (1) Aβ and mitochondrial fission protein Drp1; (2) P-Tau and Drp1; and (3) Aβ and PINK1/parkin lead to an inability to clear damaged mitochondria and other cellular debris from neurons. These events occur selectively in affected AD neurons. The purpose of our article is to highlight recent developments of a Aβ and P-Tau-induced defective autophagy and mitophagy in AD. This article also summarizes several aspects of mitochondrial dysfunction, including abnormal mitochondrial dynamics (increased fission and reduced fusion), defective mitochondrial biogenesis, reduced ATP, increased free radicals and lipid peroxidation, and decreased cytochrome c oxidase (COX) activity and calcium dyshomeostasis in AD pathogenesis. Our article also discusses how reduced levels of Drp1, Aβ, and P-Tau can enhance the clearance of damaged mitochondria and other cellular debris by autophagy and mitophagy mechanisms.
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Set KK, Sen K, Huq AHM, Agarwal R. Mitochondrial Disorders of the Nervous System: A Review. Clin Pediatr (Phila) 2019; 58:381-394. [PMID: 30607979 DOI: 10.1177/0009922818821890] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Kallol K Set
- 1 Dayton Children's Hospital, Dayton, OH, USA.,2 Wright State University Boonshoft School of Medicine, Dayton, OH, USA
| | - Kuntal Sen
- 3 Children's Hospital of Michigan, Detroit, MI, USA.,4 Wayne State University School of Medicine, Detroit, MI, USA
| | - A H M Huq
- 3 Children's Hospital of Michigan, Detroit, MI, USA.,4 Wayne State University School of Medicine, Detroit, MI, USA
| | - Rajkumar Agarwal
- 1 Dayton Children's Hospital, Dayton, OH, USA.,2 Wright State University Boonshoft School of Medicine, Dayton, OH, USA
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29
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Saneto RP. An update on Alpers-Huttenlocher syndrome: pathophysiology of disease and rational treatment designs. Expert Opin Orphan Drugs 2018. [DOI: 10.1080/21678707.2018.1540979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Russell P. Saneto
- Department of Neurology, Division of Pediatric Neurology, University of Washington and Seattle Children’s Hospital, Seattle, WA, USA
- Neuroscience Institute, Center for Integrative Brain Research, Seattle Children’s Hospital, Seattle, WA, USA
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Hayhurst H, Anagnostou ME, Bogle HJ, Grady JP, Taylor RW, Bindoff LA, McFarland R, Turnbull DM, Lax NZ. Dissecting the neuronal vulnerability underpinning Alpers' syndrome: a clinical and neuropathological study. Brain Pathol 2018; 29:97-113. [PMID: 30021052 PMCID: PMC7379503 DOI: 10.1111/bpa.12640] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 06/29/2018] [Indexed: 11/28/2022] Open
Abstract
Alpers’ syndrome is an early‐onset neurodegenerative disorder often caused by biallelic pathogenic variants in the gene encoding the catalytic subunit of polymerase‐gamma (POLG) which is essential for mitochondrial DNA (mtDNA) replication. Alpers’ syndrome is characterized by intractable epilepsy, developmental regression and liver failure which typically affects children aged 6 months–3 years. Although later onset variants are now recognized, they differ in that they are primarily an epileptic encephalopathy with ataxia. The disorder is progressive, without cure and inevitably leads to death from drug‐resistant status epilepticus, often with concomitant liver failure. Since our understanding of the mechanisms contributing the neurological features in Alpers’ syndrome is rudimentary, we performed a detailed and quantitative neuropathological study on 13 patients with clinically and histologically‐defined Alpers’ syndrome with ages ranging from 2 months to 18 years. Quantitative immunofluorescence showed severe respiratory chain deficiencies involving mitochondrial respiratory chain subunits of complex I and, to a lesser extent, complex IV in inhibitory interneurons and pyramidal neurons in the occipital cortex and in Purkinje cells of the cerebellum. Diminished densities of these neuronal populations were also observed. This study represents the largest cohort of post‐mortem brains from patients with clinically defined Alpers’ syndrome where we provide quantitative evidence of extensive complex I defects affecting interneurons and Purkinje cells for the first time. We believe interneuron and Purkinje cell pathology underpins the clinical development of seizures and ataxia seen in Alpers’ syndrome. This study also further highlights the extensive involvement of GABAergic neurons in mitochondrial disease.
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Affiliation(s)
- Hannah Hayhurst
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Maria-Eleni Anagnostou
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Helen J Bogle
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - John P Grady
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Laurence A Bindoff
- Department of Clinical Medicine, University of Bergen, Bergen, Norway.,Department of Neurology, Haukeland University, Bergen, Norway
| | - Robert McFarland
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Doug M Turnbull
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Nichola Z Lax
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
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31
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Hynynen J, Pokka T, Komulainen-Ebrahim J, Myllynen P, Kärppä M, Pylvänen L, Kälviäinen R, Sokka A, Jyrkilä A, Lähdetie J, Haataja L, Mäkitalo A, Ylikotila P, Eriksson K, Haapala P, Ansakorpi H, Hinttala R, Vieira P, Majamaa K, Rantala H, Uusimaa J. Variants p.Q1236H and p.E1143G in mitochondrial DNA polymerase gamma POLG1 are not associated with increased risk for valproate-induced hepatotoxicity or pancreatic toxicity: A retrospective cohort study of patients with epilepsy. Epilepsia 2018; 59:2125-2136. [PMID: 30255931 DOI: 10.1111/epi.14568] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 08/28/2018] [Accepted: 08/28/2018] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Previous studies have suggested that heterozygous variants p.Q1236H and p.E1143G in mitochondrial DNA polymerase gamma (POLG1) increase the risk for liver injury for patients on valproate (VPA) therapy. We assessed the prevalence of these common variants and seven other pathogenic mutations in POLG1 and determined the occurrence of VPA-induced hepatotoxicity (VHT) or pancreatic toxicity in a cohort of patients with epilepsy. METHODS Patients with epilepsy (N = 367) were retrospectively identified from medical record files and screened for mutations in POLG1. Patients who had received VPA monotherapy and carried either of the two variants, p.Q1236H or p.E1143G, without other pathogenic mutations in POLG1 (n = 33, variant group) and patients without these variants (n = 28, nonvariant group) were included in the study. Clinical data on epilepsy, characteristics of VPA treatment, risk factors for VHT, laboratory data on liver and pancreas functions, and adverse effects were collected. RESULTS A total of 122 patients had either the POLG1 p.Q1236H (n = 99) or p.E1143G (n = 24) variant in the heterozygous or homozygous state. Transient liver dysfunction was identified in three (n = 33, 9.1%) variant group patients and in one (n = 28, 3.6%) nonvariant group patient (P = 0.62). Mild to moderate elevations in liver enzymes were encountered in both groups. Furthermore, two patients on VPA polytherapy developed acute pancreatitis, and two pediatric patients with heterozygous p.Q1236H variants and mutations in IQSEC2 and GLDC, respectively, had elevated levels of VPA metabolites in urine, elevated plasma glycine, and/or increased acylglycine excretion. SIGNIFICANCE POLG1 p.Q1236H and p.E1143G variants could not be identified as statistically significant risk factors for VHT or pancreatic toxicity. We suggest that VPA treatment could be suitable for patients who harbor these common variants in the absence of other pathogenic mutations in POLG1.
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Affiliation(s)
- Johanna Hynynen
- Research Unit for Pediatrics, Pediatric Neurology, Pediatric Surgery, Child Psychiatry, Dermatology, Clinical Genetics, Obstetrics and Gynecology, Otorhinolaryngology and Ophthalmology, University of Oulu, Oulu, Finland.,Medical Research Center, Oulu University Hospital, Oulu, Finland.,Biocenter Oulu, University of Oulu, Oulu, Finland.,Department of Children and Adolescents, Division of Pediatric Neurology, Oulu University Hospital, Oulu, Finland
| | - Tytti Pokka
- Research Unit for Pediatrics, Pediatric Neurology, Pediatric Surgery, Child Psychiatry, Dermatology, Clinical Genetics, Obstetrics and Gynecology, Otorhinolaryngology and Ophthalmology, University of Oulu, Oulu, Finland.,Department of Children and Adolescents, Division of Pediatric Neurology, Oulu University Hospital, Oulu, Finland
| | - Jonna Komulainen-Ebrahim
- Research Unit for Pediatrics, Pediatric Neurology, Pediatric Surgery, Child Psychiatry, Dermatology, Clinical Genetics, Obstetrics and Gynecology, Otorhinolaryngology and Ophthalmology, University of Oulu, Oulu, Finland.,Medical Research Center, Oulu University Hospital, Oulu, Finland.,Biocenter Oulu, University of Oulu, Oulu, Finland.,Department of Children and Adolescents, Division of Pediatric Neurology, Oulu University Hospital, Oulu, Finland
| | | | - Mikko Kärppä
- Medical Research Center, Oulu University Hospital, Oulu, Finland.,Department of Neurology, Oulu University Hospital, Oulu, Finland.,Research Unit of Clinical Neuroscience, Neurology, University of Oulu, Oulu, Finland
| | - Laura Pylvänen
- Department of Neurology, Oulu University Hospital, Oulu, Finland
| | - Reetta Kälviäinen
- Department of Neurology, Kuopio University Hospital, Kuopio, Finland.,Institute of Clinical Medicine, School of Medicine, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
| | - Arja Sokka
- Institute of Clinical Medicine, School of Medicine, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland.,Department of Pediatric Neurology, Kuopio University Hospital, Kuopio, Finland
| | - Aino Jyrkilä
- Institute of Clinical Medicine, School of Medicine, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland.,Department of Pediatric Neurology, Kuopio University Hospital, Kuopio, Finland
| | - Jaana Lähdetie
- Department of Child Neurology, University of Turku and Turku University Central Hospital, Turku, Finland
| | - Leena Haataja
- Department of Pediatric Neurology, Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Anna Mäkitalo
- Department of Child Neurology, University of Turku and Turku University Central Hospital, Turku, Finland.,Department of Geriatric Medicine, University of Turku, Turku, Finland
| | - Pauli Ylikotila
- Department of Neurology, Institute of Clinical Medicine, University of Turku, Turku, Finland.,Division of Clinical Neurosciences, Turku University Hospital, Turku, Finland
| | - Kai Eriksson
- Tampere Center for Child Health Research and Pediatric Neurology, Tampere University Hospital, Tampere, Finland
| | - Piia Haapala
- Outpatient Intellectual Disabilities Clinic, Tampere University Hospital, Tampere, Finland
| | - Hanna Ansakorpi
- Medical Research Center, Oulu University Hospital, Oulu, Finland.,Department of Neurology, Oulu University Hospital, Oulu, Finland.,Research Unit of Clinical Neuroscience, Neurology, University of Oulu, Oulu, Finland
| | - Reetta Hinttala
- Research Unit for Pediatrics, Pediatric Neurology, Pediatric Surgery, Child Psychiatry, Dermatology, Clinical Genetics, Obstetrics and Gynecology, Otorhinolaryngology and Ophthalmology, University of Oulu, Oulu, Finland.,Medical Research Center, Oulu University Hospital, Oulu, Finland.,Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Päivi Vieira
- Research Unit for Pediatrics, Pediatric Neurology, Pediatric Surgery, Child Psychiatry, Dermatology, Clinical Genetics, Obstetrics and Gynecology, Otorhinolaryngology and Ophthalmology, University of Oulu, Oulu, Finland.,Medical Research Center, Oulu University Hospital, Oulu, Finland.,Department of Children and Adolescents, Division of Pediatric Neurology, Oulu University Hospital, Oulu, Finland
| | - Kari Majamaa
- Medical Research Center, Oulu University Hospital, Oulu, Finland.,Department of Neurology, Oulu University Hospital, Oulu, Finland.,Research Unit of Clinical Neuroscience, Neurology, University of Oulu, Oulu, Finland
| | - Heikki Rantala
- Research Unit for Pediatrics, Pediatric Neurology, Pediatric Surgery, Child Psychiatry, Dermatology, Clinical Genetics, Obstetrics and Gynecology, Otorhinolaryngology and Ophthalmology, University of Oulu, Oulu, Finland.,Medical Research Center, Oulu University Hospital, Oulu, Finland.,Department of Children and Adolescents, Division of Pediatric Neurology, Oulu University Hospital, Oulu, Finland
| | - Johanna Uusimaa
- Research Unit for Pediatrics, Pediatric Neurology, Pediatric Surgery, Child Psychiatry, Dermatology, Clinical Genetics, Obstetrics and Gynecology, Otorhinolaryngology and Ophthalmology, University of Oulu, Oulu, Finland.,Medical Research Center, Oulu University Hospital, Oulu, Finland.,Biocenter Oulu, University of Oulu, Oulu, Finland.,Department of Children and Adolescents, Division of Pediatric Neurology, Oulu University Hospital, Oulu, Finland
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Alves CAPF, Gonçalves FG, Grieb D, Lucato LT, Goldstein AC, Zuccoli G. Neuroimaging of Mitochondrial Cytopathies. Top Magn Reson Imaging 2018; 27:219-240. [PMID: 30086109 DOI: 10.1097/rmr.0000000000000173] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Mitochondrial diseases are a complex and heterogeneous group of genetic disorders that occur as a result of either nuclear DNA or mitochondrial DNA pathogenic variants, leading to a decrease in oxidative phosphorylation and cellular energy (ATP) production. Increasing knowledge about molecular, biochemical, and genetic abnormalities related to mitochondrial dysfunction has expanded the neuroimaging phenotypes of mitochondrial disorders. As a consequence of this growing field, the imaging recognition patterns of mitochondrial cytopathies are continually evolving. In this review, we describe the main neuroimaging characteristics of pediatric mitochondrial diseases, ranging from classical to more recent and challenging features. Due to the increased knowledge about the imaging findings of mitochondrial cytopathies, the pediatric neuroradiologist plays a crucial role in the diagnosis and evaluation of these patients.
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Affiliation(s)
| | | | - Dominik Grieb
- Department of Radiology and Neuroradiology, Sana Kliniken Duisburg, Germany
| | - Leandro Tavares Lucato
- Neuroradiology Section, Hospital das Clínicas- HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP, Brazil
| | - Amy C Goldstein
- Division of Human Genetics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA
| | - Giulio Zuccoli
- Department of Radiology, University of Pittsburgh School of Medicine, Director of Pediatric Neuroradiology, Children Hospital of Pittsburgh, Pittsburgh, PA
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33
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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: 22] [Impact Index Per Article: 3.7] [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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Abstract
History A 10-year-old girl with global developmental delay and attention deficit hyperactivity disorder was transferred from an outside hospital because of confusion and multiple episodes of left face and arm jerking. Physical examination revealed normal muscle bulk, strength, and tone in the bilateral upper and lower extremities but insuppressible left arm and jaw twitching Lumbar puncture revealed no white or red blood cells, a normal glucose level of 55 mg/dL (3.0 mmol/L) (normal range, 50-80 mg/dL [2.8-4.4 mmol/L]), and an elevated protein level of 81.6 mg/dL (normal range, 15-60 mg/100 dL). A comprehensive metabolic panel revealed lactic acidosis. The patient was initially started on levetiracetam, phenobarbital, phenytoin, and topiramate for status epilepticus. Hepatic dysfunction was not present at initial admission but developed 2 months later, with an alanine aminotransferase level of 90-406 U/L (1.5-6.8 μkat/L) (normal range, 8-37 U/L [0.13-0.62 μkat/L]) and aspartate aminotransferase in the range of 75-187 U/L (1.2-3.1 μkat/L) (normal range, 8-35 U/L [0.13-0.58 μkat/L]). Electroencephalography revealed right parietal and occipital spike-and-wave discharges, with bursts of up to 20 seconds, which were indicative of subclinical status epilepticus. The family history was remarkable for a sister with head lag, developmental delay, seizure disorder, and liver failure.
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Affiliation(s)
- Judy Wu
- From the Department of Radiology, University of Chicago, Pritzker School of Medicine, 5841 S Maryland Ave, Chicago, IL 60637
| | - Carina Yang
- From the Department of Radiology, University of Chicago, Pritzker School of Medicine, 5841 S Maryland Ave, Chicago, IL 60637
| | - John Collins
- From the Department of Radiology, University of Chicago, Pritzker School of Medicine, 5841 S Maryland Ave, Chicago, IL 60637
| | - Daniel Thomas Ginat
- From the Department of Radiology, University of Chicago, Pritzker School of Medicine, 5841 S Maryland Ave, Chicago, IL 60637
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Abstract
Ataxia is one of the most frequent symptoms of mitochondrial disease. In most cases it occurs as part of a syndromic disorder and the combination of ataxia with other neurologic involvement such as epilepsy is common. Mitochondrial ataxias can be caused by disturbance of the cerebellum and its connections, involvement of proprioception (i.e., sensory ataxia) or a combination of both (spinocerebellar). There are no specific features that define an ataxia as mitochondrial, except perhaps the tendency for it to occur together with involvement of multiple other sites, both in the nervous system and outside. In this review we will concentrate on the mitochondrial disorders in which ataxia is a prominent and consistent feature and focus on the clinical features and genetic causes.
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Affiliation(s)
- Hilary J Vernon
- McKusick-Nathans Institute of Genetic Medicine, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Laurence A Bindoff
- Department of Clinical Medicine, University of Bergen and Department of Neurology, Haukeland University Hospital, Bergen, Norway.
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Park S, Kang HC, Lee JS, Park YN, Kim S, Koh H. Alpers-Huttenlocher Syndrome First Presented with Hepatic Failure: Can Liver Transplantation Be Considered as Treatment Option? Pediatr Gastroenterol Hepatol Nutr 2017; 20:259-262. [PMID: 29302508 PMCID: PMC5750381 DOI: 10.5223/pghn.2017.20.4.259] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 05/18/2017] [Accepted: 05/26/2017] [Indexed: 11/18/2022] Open
Abstract
Mitochondria play essential role in eukaryotic cells including in the oxidative phosphorylation and generation of adenosine triphosphate via the electron-transport chain. Therefore, defects in mitochondrial DNA (mtDNA) can result in mitochondrial dysfunction which leads to various mitochondrial disorders that may present with various neurologic and non-neurologic manifestations. Mutations in the nuclear gene polymerase gamma (POLG) are associated with mtDNA depletions, and Alpers-Huttenlocher syndrome is one of the most severe manifestations of POLG mutation characterized by the clinical triad of intractable seizures, psychomotor regression, and liver failure. The hepatic manifestation usually occurs late in the disease's course, but in some references, hepatitis was reportedly the first manifestation. Liver transplantation was considered contraindicated in Alpers-Huttenlocher syndrome due to its poor prognosis. We acknowledged a patient with the first manifestation of the disease being hepatic failure who eventually underwent liver transplantation, and whose neurological outcome improved after cocktail therapy.
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Affiliation(s)
- Sowon Park
- Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Hoon-Chul Kang
- Division of Neurology, Department of Pediatrics, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Jin-Sung Lee
- Division of Clinical Genetics, Department of Pediatrics, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Young Nyun Park
- Department of Pathology, Yonsei University College of Medicine, Seoul, Korea
| | - Seung Kim
- Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Hong Koh
- Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Korea
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Saneto RP. Epilepsy and Mitochondrial Dysfunction. JOURNAL OF INBORN ERRORS OF METABOLISM AND SCREENING 2017. [DOI: 10.1177/2326409817733012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Russell P. Saneto
- Division of Pediatric Neurology, Department of Neurology, University of Washington, Seattle, WA, USA
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Abstract
Mitochondria are intracellular organelles responsible for adenosine triphosphate production. The strict control of intracellular energy needs require proper mitochondrial functioning. The mitochondria are under dual controls of mitochondrial DNA (mtDNA) and nuclear DNA (nDNA). Mitochondrial dysfunction can arise from changes in either mtDNA or nDNA genes regulating function. There are an estimated ∼1500 proteins in the mitoproteome, whereas the mtDNA genome has 37 proteins. There are, to date, ∼275 genes shown to give rise to disease. The unique physiology of mitochondrial functioning contributes to diverse gene expression. The onset and range of phenotypic expression of disease is diverse, with onset from neonatal to seventh decade of life. The range of dysfunction is heterogeneous, ranging from single organ to multisystem involvement. The complexity of disease expression has severely limited gene discovery. Combining phenotypes with improvements in gene sequencing strategies are improving the diagnosis process. This chapter focuses on the interplay of the unique physiology and gene discovery in the current knowledge of genetically derived mitochondrial disease.
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Affiliation(s)
- Russell P Saneto
- Seattle Children's Hospital/University of Washington, Seattle, WA, United States.
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39
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Clinical effects of chemical exposures on mitochondrial function. Toxicology 2017; 391:90-99. [PMID: 28757096 DOI: 10.1016/j.tox.2017.07.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 07/07/2017] [Accepted: 07/17/2017] [Indexed: 12/16/2022]
Abstract
Mitochondria are critical for the provision of ATP for cellular energy requirements. Tissue and organ functions are dependent on adequate ATP production, especially when energy demand is high. Mitochondria also play a role in a vast array of important biochemical pathways including apoptosis, generation and detoxification of reactive oxygen species, intracellular calcium regulation, steroid hormone and heme synthesis, and lipid metabolism. The complexity of mitochondrial structure and function facilitates its diverse roles but also enhances its vulnerability. Primary disorders of mitochondrial bioenergetics, or Primary Mitochondrial Diseases (PMD) are due to inherited genetic defects in the nuclear or mitochondrial genomes that result in defective oxidative phosphorylation capacity and cellular energy production. Secondary mitochondrial dysfunction is observed in a wide range of diseases such as Alzheimer's and Parkinson's disease. Several lines of evidence suggest that environmental exposures cause substantial mitochondrial dysfunction. Whereby literature from experimental and human studies on exposures associated with Alzheimer's and Parkinson's diseases exist, the significance of exposures as potential triggers in Primary Mitochondrial Disease (PMD) is an emerging clinical question that has not been systematically studied.
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40
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Chan SSL. Inherited mitochondrial genomic instability and chemical exposures. Toxicology 2017; 391:75-83. [PMID: 28756246 DOI: 10.1016/j.tox.2017.07.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 06/12/2017] [Accepted: 07/24/2017] [Indexed: 12/21/2022]
Abstract
There are approximately 1500 proteins that are needed for mitochondrial structure and function, most of which are encoded in the nuclear genome (Calvo et al., 2006). Each mitochondrion has its own genome (mtDNA), which in humans encodes 13 polypeptides, 22 tRNAs and 2 rRNAs required for oxidative phosphorylation. The mitochondrial genome of humans and most vertebrates is approximately 16.5kbp, double-stranded, circular, with few non-coding bases. Thus, maintaining mtDNA stability, that is, the ability of the cell to maintain adequate levels of mtDNA template for oxidative phosphorylation is essential and can be impacted by the level of mtDNA mutation currently within the cell or mitochondrion, but also from errors made during normal mtDNA replication, defects in mitochondrial quality control mechanisms, and exacerbated by exposures to exogenous and/or endogenous genotoxic agents. In this review, we expand on the origins and consequences of mtDNA instability, the current state of research regarding the mechanisms by which mtDNA instability can be overcome by cellular and chemical interventions, and the future of research and treatments for mtDNA instability.
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Affiliation(s)
- Sherine S L Chan
- Drug Discovery and Biomedical Sciences, College of Pharmacy, Medical University of South Carolina, Charleston, SC 29425, United States; Neuroene Therapeutics, Mt. Pleasant, SC 29464, United States.
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41
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London F, Hadhoum N, Outteryck O, Vermersch P, Zéphir H. Late-onset of Alpers-Huttenlocher syndrome: an unusual cause of refractory epilepsy and liver failure. Acta Neurol Belg 2017; 117:399-401. [PMID: 27422324 DOI: 10.1007/s13760-016-0672-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 07/08/2016] [Indexed: 10/21/2022]
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42
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Abstract
Mitochondrial diseases are a group of genetic disorders that are characterized by defects in oxidative phosphorylation and caused by mutations in genes in the nuclear DNA (nDNA) and mitochondrial DNA (mtDNA) that encode structural mitochondrial proteins or proteins involved in mitochondrial function. Mitochondrial diseases are the most common group of inherited metabolic disorders and are among the most common forms of inherited neurological disorders. One of the challenges of mitochondrial diseases is the marked clinical variation seen in patients, which can delay diagnosis. However, advances in next-generation sequencing techniques have substantially improved diagnosis, particularly in children. Establishing a genetic diagnosis allows patients with mitochondrial diseases to have reproductive options, but this is more challenging for women with pathogenetic mtDNA mutations that are strictly maternally inherited. Recent advances in in vitro fertilization techniques, including mitochondrial donation, will offer a better reproductive choice for these women in the future. The treatment of patients with mitochondrial diseases remains a challenge, but guidelines are available to manage the complications of disease. Moreover, an increasing number of therapeutic options are being considered, and with the development of large cohorts of patients and biomarkers, several clinical trials are in progress.
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When to Suspect and How to Diagnose Mitochondrial Disorders? Indian J Pediatr 2016; 83:1157-63. [PMID: 26759002 DOI: 10.1007/s12098-015-1932-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 10/16/2015] [Indexed: 01/26/2023]
Abstract
Disorders of the mitochondrial respiratory chain are an exceedingly diverse group. The clinical features can affect any tissue or organ and occur at any age, with any mode of inheritance. The diagnosis of mitochondrial disorders requires knowledge of the clinical phenotypes and access to a wide range of laboratory techniques. A few syndromes are associated with a specific genetic defect and in these cases it is appropriate to proceed directly to an appropriate test of blood or urine. In most cases, however, the best strategy starts with biochemical and histochemical studies on a muscle biopsy. Appropriate molecular genetic studies can then be chosen, based on these results and the clinical picture. Unfortunately, there is currently limited availability of respiratory chain studies in India. Exome sequencing is undertaken increasingly often; without preceding mitochondrial studies, this can lead to misleading results.
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Anagnostou ME, Ng YS, Taylor RW, McFarland R. Epilepsy due to mutations in the mitochondrial polymerase gamma (POLG)
gene: A clinical and molecular genetic review. Epilepsia 2016; 57:1531-1545. [DOI: 10.1111/epi.13508] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/26/2016] [Indexed: 01/01/2023]
Affiliation(s)
- Maria-Eleni Anagnostou
- Wellcome Trust Centre for Mitochondrial Research; Institute of Neuroscience; Newcastle University; Newcastle upon Tyne United Kingdom
| | - Yi Shiau Ng
- Wellcome Trust Centre for Mitochondrial Research; Institute of Neuroscience; Newcastle University; Newcastle upon Tyne United Kingdom
| | - Robert W. Taylor
- Wellcome Trust Centre for Mitochondrial Research; Institute of Neuroscience; Newcastle University; Newcastle upon Tyne United Kingdom
| | - Robert McFarland
- Wellcome Trust Centre for Mitochondrial Research; Institute of Neuroscience; Newcastle University; Newcastle upon Tyne United Kingdom
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45
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Saneto RP. Alpers-Huttenlocher syndrome: the role of a multidisciplinary health care team. J Multidiscip Healthc 2016; 9:323-33. [PMID: 27555780 PMCID: PMC4968991 DOI: 10.2147/jmdh.s84900] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Alpers–Huttenlocher syndrome (AHS) is a mitochondrial DNA-depletion syndrome. Age of onset is bimodal: early onset at 2–4 years and later adolescent onset at 17–24 years of age. Early development is usually normal, with epilepsy heralding the disorder in ~50% of patients. The onset of seizures is coupled with progressive cognitive decline. Hepatopathy is variable, and when present is a progressive dysfunction leading to liver failure in many cases. These features of seizures, cognitive degeneration, and hepatopathy represent the “classic triad” of AHS. However, most patients develop other system involvement. Therefore, although AHS is ultimately a lethal disorder, medical care is required for sustained quality of life. Frequently, additional organ systems – gastrointestinal, respiratory, nutritional, and psychiatric – abnormalities appear and need treatment. Rarely, cardiovascular dysfunction and even pregnancy complicate medical treatment. Optimal care requires a team of physicians and caretakers to make sure quality of life is optimized. The care team, together with the family and palliative care specialists, need to be in communication as the disease progresses and medical changes occur. Although the unpredictable losses of function challenge medical care, the team approach can foster the individual quality-of-life care needed for the patient and family.
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Affiliation(s)
- Russell P Saneto
- Department of Neurology, University of Washington; Division of Pediatric Neurology, Seattle Children's Hospital, Seattle, WA, USA
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46
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Abstract
The goal of pharmacogenetic research is to assist clinicians in predicting patient response to medications when genetic variations are identified. The pharmacogenetic variation of antiepileptic drug response and side effects has yielded findings that have been included in drug labeling and guidelines. The goal of this review is to provide a brief overview of the pharmacogenetic research on antiepileptic drugs. It will focus on findings that have been included in drug labeling, guidelines, and candidate pharmacogenetic variation. Overall, several genes have been included in guidelines by national and international organizations; however, much work is needed to implement and evaluate their use in clinical settings.
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Affiliation(s)
- D Parker
- Associate Professor, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan
| | - E J Sanders
- Research Assistant, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan
| | - K J Burghardt
- Assistant Professor, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan,
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47
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Janssen W, Quaegebeur A, Van Goethem G, Ann L, Smets K, Vandenberghe R, Van Paesschen W. The spectrum of epilepsy caused by POLG mutations. Acta Neurol Belg 2016; 116:17-25. [PMID: 26104464 DOI: 10.1007/s13760-015-0499-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 06/08/2015] [Indexed: 12/21/2022]
Abstract
Mutations in POLG are increasingly recognized as a cause of refractory occipital lobe epilepsy (OLE) and status epilepticus (SE). Our aim was to describe the epilepsy syndrome in seven patients with POLG mutations. We retrospectively reviewed the medical records of seven patients with POLG mutations and epilepsy. Mutation analysis was performed by direct sequencing of the coding exons of the POLG gene. Disease onset was at a median age of 18 years (range 12-26). Epilepsy was the presenting problem in six patients. All had focal seizures, with motor (n = 6) and visual (n = 6) phenomena. Six patients had secondarily generalized seizures and two patients had myoclonic seizures. Six patients had one or more episodes of refractory SE, including focal (n = 5), subtle (n = 4), myoclonic (n = 2) and convulsive (n = 3) SE. During or after SE, brain MRI showed lesions affecting the occipital lobe in all patients, probably due to continuous epileptic activity. Five of the six patients with SE died during treatment of SE, one due to valproate-induced hepatotoxicity. Associated clinical symptoms were ataxia (n = 6), polyneuropathy (n = 6), progressive external ophthalmoplegia (PEO) (n = 3) and migraine (n = 3). Epilepsy may be the first and dominant neurological problem caused by POLG mutations. The epilepsy may be severe and the condition of the patient may end in fatal SE. Refractory OLE and SE in a patient with polyneuropathy, ataxia, PEO or migraine warrant screening for POLG mutations. In this clinical setting, valproate should not be given in view of the risk of fatal hepatotoxicity.
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Affiliation(s)
- Wouter Janssen
- Department of Neurology, University Hospitals Leuven, Herestraat 49, 3000, Louvain, Belgium.
| | - Annelies Quaegebeur
- Department of Neurology, University Hospitals Leuven, Herestraat 49, 3000, Louvain, Belgium
| | - Gert Van Goethem
- Neurogenetics Group, Department of Molecular Genetics, VIB, Antwerp, Belgium
- Laboratory of Neurogenetics, Institute Born-Bunge, Antwerp, Belgium
- University of Antwerpen, Antwerp, Belgium
- Department of Neurology, University Hospital Antwerpen, Antwerp, Belgium
| | - Löfgren Ann
- Laboratory of Neurogenetics, Institute Born-Bunge, Antwerp, Belgium
- University of Antwerpen, Antwerp, Belgium
| | - Katrien Smets
- Neurogenetics Group, Department of Molecular Genetics, VIB, Antwerp, Belgium
- Laboratory of Neurogenetics, Institute Born-Bunge, Antwerp, Belgium
- University of Antwerpen, Antwerp, Belgium
- Department of Neurology, University Hospital Antwerpen, Antwerp, Belgium
| | - Rik Vandenberghe
- Department of Neurology, University Hospitals Leuven, Herestraat 49, 3000, Louvain, Belgium
| | - Wim Van Paesschen
- Department of Neurology, University Hospitals Leuven, Herestraat 49, 3000, Louvain, Belgium.
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48
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Rahn JJ, Bestman JE, Stackley KD, Chan SSL. Zebrafish lacking functional DNA polymerase gamma survive to juvenile stage, despite rapid and sustained mitochondrial DNA depletion, altered energetics and growth. Nucleic Acids Res 2015; 43:10338-52. [PMID: 26519465 PMCID: PMC4666367 DOI: 10.1093/nar/gkv1139] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 10/16/2015] [Indexed: 01/05/2023] Open
Abstract
DNA polymerase gamma (POLG) is essential for replication and repair of mitochondrial DNA (mtDNA). Mutations in POLG cause mtDNA instability and a diverse range of poorly understood human diseases. Here, we created a unique Polg animal model, by modifying polg within the critical and highly conserved polymerase domain in zebrafish. polg+/− offspring were indistinguishable from WT siblings in multiple phenotypic and biochemical measures. However, polg−/− mutants developed severe mtDNA depletion by one week post-fertilization (wpf), developed slowly and had regenerative defects, yet surprisingly survived up to 4 wpf. An in vivo mtDNA polymerase activity assay utilizing ethidium bromide (EtBr) to deplete mtDNA, showed that polg+/− and WT zebrafish fully recover mtDNA content two weeks post-EtBr removal. EtBr further reduced already low levels of mtDNA in polg−/− animals, but mtDNA content did not recover following release from EtBr. Despite significantly decreased respiration that corresponded with tissue-specific levels of mtDNA, polg−/− animals had WT levels of ATP and no increase in lactate. This zebrafish model of mitochondrial disease now provides unique opportunities for studying mtDNA instability from multiple angles, as polg−/− mutants can survive to juvenile stage, rather than lose viability in embryogenesis as seen in Polg mutant mice.
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Affiliation(s)
- Jennifer J Rahn
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Jennifer E Bestman
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Krista D Stackley
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Sherine S L Chan
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425, USA
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49
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Frye RE, Rose S, Slattery J, MacFabe DF. Gastrointestinal dysfunction in autism spectrum disorder: the role of the mitochondria and the enteric microbiome. MICROBIAL ECOLOGY IN HEALTH AND DISEASE 2015; 26:27458. [PMID: 25956238 PMCID: PMC4425813 DOI: 10.3402/mehd.v26.27458] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Revised: 04/09/2015] [Accepted: 04/10/2015] [Indexed: 12/26/2022]
Abstract
Autism spectrum disorder (ASD) affects a significant number of individuals worldwide with the prevalence continuing to grow. It is becoming clear that a large subgroup of individuals with ASD demonstrate abnormalities in mitochondrial function as well as gastrointestinal (GI) symptoms. Interestingly, GI disturbances are common in individuals with mitochondrial disorders and have been reported to be highly prevalent in individuals with co-occurring ASD and mitochondrial disease. The majority of individuals with ASD and mitochondrial disorders do not manifest a primary genetic mutation, raising the possibility that their mitochondrial disorder is acquired or, at least, results from a combination of genetic susceptibility interacting with a wide range of environmental triggers. Mitochondria are very sensitive to both endogenous and exogenous environmental stressors such as toxicants, iatrogenic medications, immune activation, and metabolic disturbances. Many of these same environmental stressors have been associated with ASD, suggesting that the mitochondria could be the biological link between environmental stressors and neurometabolic abnormalities associated with ASD. This paper reviews the possible links between GI abnormalities, mitochondria, and ASD. First, we review the link between GI symptoms and abnormalities in mitochondrial function. Second, we review the evidence supporting the notion that environmental stressors linked to ASD can also adversely affect both mitochondria and GI function. Third, we review the evidence that enteric bacteria that are overrepresented in children with ASD, particularly Clostridia spp., produce short-chain fatty acid metabolites that are potentially toxic to the mitochondria. We provide an example of this gut–brain connection by highlighting the propionic acid rodent model of ASD and the clinical evidence that supports this animal model. Lastly, we discuss the potential therapeutic approaches that could be helpful for GI symptoms in ASD and mitochondrial disorders. To this end, this review aims to help better understand the underlying pathophysiology associated with ASD that may be related to concurrent mitochondrial and GI dysfunction.
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Affiliation(s)
- Richard E Frye
- Autism Research Program, Arkansas Children's Hospital Research Institute, Little Rock, AR, USA.,Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA;
| | - Shannon Rose
- Autism Research Program, Arkansas Children's Hospital Research Institute, Little Rock, AR, USA.,Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - John Slattery
- Autism Research Program, Arkansas Children's Hospital Research Institute, Little Rock, AR, USA.,Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Derrick F MacFabe
- Kilee Patchell-Evans Autism Research Group, Division of Developmental Disabilities, Departments of Psychology and Psychiatry, University of Western Ontario, London, ON, Canada
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50
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Zabalza R, Nurminen A, Kaguni LS, Garesse R, Gallardo ME, Bornstein B. Co-occurrence of four nucleotide changes associated with an adult mitochondrial ataxia phenotype. BMC Res Notes 2014; 7:883. [PMID: 25488682 PMCID: PMC4295309 DOI: 10.1186/1756-0500-7-883] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 11/18/2014] [Indexed: 11/19/2022] Open
Abstract
Background Mitochondrial DNA maintenance disorders are an important cause of hereditary ataxia syndrome, and the majority are associated with mutations in the gene encoding the catalytic subunit of the mitochondrial DNA polymerase (DNA polymerase gamma), POLG. Mutations resulting in the amino acid substitutions A467T and W748S are the most common genetic causes of inherited cerebellar ataxia in Europe. Methods We report here a POLG mutational screening in a family with a mitochondrial ataxia phenotype. To evaluate the likely pathogenicity of each of the identified changes, a 3D structural analysis of the PolG protein was carried out, using the Alpers mutation clustering tool reported previously. Results Three novel nucleotide changes and the p.Q1236H polymorphism have been identified in the affected members of the pedigree. Computational analysis suggests that the p.K601E mutation is likely the major contributing factor to the pathogenic phenotype. Conclusions Computational analysis of the PolG protein suggests that the p.K601E mutation is likely the most significant contributing factor to a pathogenic phenotype. However, the co-occurrence of multiple POLG alleles may be necessary in the development an adult-onset mitochondrial ataxia phenotype.
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Affiliation(s)
| | | | | | | | - M Esther Gallardo
- Departamento de Bioquímica, Facultad de Medicina, Instituto de Investigaciones Biomédicas "Alberto Sols" UAM-CSIC and Centro de Investigación Biomédica en Red (CIBERER), Madrid, Spain.
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