1
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Boopathy S, Luce BE, Lugo CM, Hakim P, McDonald J, Kim HL, Ponce J, Ueberheide BM, Chao LH. Identification of SLC25A46 interaction interfaces with mitochondrial membrane fusogens Opa1 and Mfn2. J Biol Chem 2024:107740. [PMID: 39222684 DOI: 10.1016/j.jbc.2024.107740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 07/27/2024] [Accepted: 08/23/2024] [Indexed: 09/04/2024] Open
Abstract
Mitochondrial fusion requires the sequential merger of four bilayers to two. The outer-membrane solute carrier protein SLC25A46 interacts with both the outer and inner-membrane dynamin family GTPases Mfn1/2 and Opa1. While SLC25A46 levels are known to affect mitochondrial morphology, how SLC25A46 interacts with Mfn1/2 and Opa1 to regulate membrane fusion is not understood. In this study, we use crosslinking mass-spectrometry and AlphaFold 2 modeling to identify interfaces mediating a SLC25A46 interactions with Opa1 and Mfn2. We reveal that the bundle signaling element of Opa1 interacts with SLC25A46, and present evidence of a Mfn2 interaction involving the SLC25A46 cytosolic face. We validate these newly identified interaction interfaces and show that they play a role in mitochondrial network maintenance.
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Affiliation(s)
- Sivakumar Boopathy
- Department of Molecular Biology, Massachusetts General Hospital, Boston MA 02114, USA; Department of Genetics, Harvard Medical School, Boston MA 02115, USA
| | - Bridget E Luce
- Department of Molecular Biology, Massachusetts General Hospital, Boston MA 02114, USA
| | - Camila Makhlouta Lugo
- Department of Molecular Biology, Massachusetts General Hospital, Boston MA 02114, USA
| | - Pusparanee Hakim
- Department of Molecular Biology, Massachusetts General Hospital, Boston MA 02114, USA
| | - Julie McDonald
- Department of Molecular Biology, Massachusetts General Hospital, Boston MA 02114, USA
| | - Ha Lin Kim
- Department of Molecular Biology, Massachusetts General Hospital, Boston MA 02114, USA
| | - Jackeline Ponce
- Proteomics Resource Center, Division of Advanced Research Technologies, New York University Langone Health Center, New York NY 10016, USA
| | - Beatrix M Ueberheide
- Proteomics Resource Center, Division of Advanced Research Technologies, New York University Langone Health Center, New York NY 10016, USA; Department of Biochemistry and Molecular Pharmacology, New York University Langone Health Center, New York NY 10016, USA
| | - Luke H Chao
- Department of Molecular Biology, Massachusetts General Hospital, Boston MA 02114, USA; Department of Genetics, Harvard Medical School, Boston MA 02115, USA
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2
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Guillaume A, Stejskal V, Smits G, Kelen D. A novel homozygous variant in SLC25A46 gene associated with pontocerebellar hypoplasia type 1E: a case report. Front Pediatr 2024; 12:1303772. [PMID: 38464896 PMCID: PMC10920260 DOI: 10.3389/fped.2024.1303772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 02/15/2024] [Indexed: 03/12/2024] Open
Abstract
Neonatal encephalopathy (NE) is a complex clinical condition with diverse etiologies. Hypoxic-ischemic encephalopathy (HIE) is a major contributor to NE cases. However, distinguishing NE subtypes, such as pontocerebellar hypoplasia type 1E (PCH1E), from HIE can be challenging due to overlapping clinical features. Here, we present a case of PCH1E in a neonate with a homozygous mutation c.72delT p. (Phe24LeufsTer20) in the SLC25A46 gene. The severity of PCH1E associated NE highlighted the significance of early recognition to guide appropriate clinical management.
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Affiliation(s)
- Adrien Guillaume
- Neonatal Intensive Care Unit, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | | | - Guillaume Smits
- Center of Human Genetics, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Dorottya Kelen
- Neonatal Intensive Care Unit, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles (ULB), Brussels, Belgium
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3
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Nguyen T, Shabot S, Yngve D, Abouleish A. Anesthetic Management for a Child With a Newly Identified Mitochondrial Disease SLC25A46 Mutation: A Case Report. Cureus 2023; 15:e47076. [PMID: 38021708 PMCID: PMC10645459 DOI: 10.7759/cureus.47076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/15/2023] [Indexed: 12/01/2023] Open
Abstract
SLC25A46 mutation is a newly recognized mitochondrial mutation causing neurological and muscular abnormalities. We describe a first-ever report of the anesthetic management of a seven-year-old boy with an SLC25A46 mutation during a major orthopedic procedure. The patient was nonverbal and presented with cerebral visual impairment, torticollis, and lower extremity contractures. Because of his new diagnosis of mitochondrial disease and history of delayed awakening after anesthesia, we performed general anesthesia with sevoflurane, a low-dose ketamine infusion, and small doses of fentanyl while avoiding propofol and maintaining normoglycemia and normothermia. No postoperative complications were noted during the recovery period.
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Affiliation(s)
- Thong Nguyen
- Anesthesiology and Perioperative Medicine, Texas Children's Hospital, Houston, USA
| | - Sarah Shabot
- Anesthesiology and Perioperative Medicine, University of Texas Medical Branch, Galveston, USA
| | - David Yngve
- Orthopedic Surgery and Rehabilitation, University of Texas Medical Branch, Galveston, USA
| | - Amr Abouleish
- Anesthesiology and Perioperative Medicine, University of Texas Medical Branch, Galveston, USA
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4
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Schuettpelz J, Janer A, Antonicka H, Shoubridge EA. The role of the mitochondrial outer membrane protein SLC25A46 in mitochondrial fission and fusion. Life Sci Alliance 2023; 6:e202301914. [PMID: 36977595 PMCID: PMC10052876 DOI: 10.26508/lsa.202301914] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 03/08/2023] [Accepted: 03/10/2023] [Indexed: 03/30/2023] Open
Abstract
Mutations in SLC25A46 underlie a wide spectrum of neurodegenerative diseases associated with alterations in mitochondrial morphology. We established an SLC25A46 knock-out cell line in human fibroblasts and studied the pathogenicity of three variants (p.T142I, p.R257Q, and p.E335D). Mitochondria were fragmented in the knock-out cell line and hyperfused in all pathogenic variants. The loss of SLC25A46 led to abnormalities in the mitochondrial cristae ultrastructure that were not rescued by the expression of the variants. SLC25A46 was present in discrete puncta at mitochondrial branch points and tips of mitochondrial tubules, co-localizing with DRP1 and OPA1. Virtually, all fission/fusion events were demarcated by a SLC25A46 focus. SLC25A46 co-immunoprecipitated with the fusion machinery, and loss of function altered the oligomerization state of OPA1 and MFN2. Proximity interaction mapping identified components of the ER membrane, lipid transfer proteins, and mitochondrial outer membrane proteins, indicating that it is present at interorganellar contact sites. SLC25A46 loss of function led to altered mitochondrial lipid composition, suggesting that it may facilitate interorganellar lipid flux or play a role in membrane remodeling associated with mitochondrial fusion and fission.
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Affiliation(s)
- Jana Schuettpelz
- Department of Human Genetics, Montreal Neurological Institute, McGill University, Montreal, Canada
| | - Alexandre Janer
- Department of Human Genetics, Montreal Neurological Institute, McGill University, Montreal, Canada
| | - Hana Antonicka
- Department of Human Genetics, Montreal Neurological Institute, McGill University, Montreal, Canada
| | - Eric A Shoubridge
- Department of Human Genetics, Montreal Neurological Institute, McGill University, Montreal, Canada
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5
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Brischigliaro M, Fernandez-Vizarra E, Viscomi C. Mitochondrial Neurodegeneration: Lessons from Drosophila melanogaster Models. Biomolecules 2023; 13:378. [PMID: 36830747 PMCID: PMC9953451 DOI: 10.3390/biom13020378] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/09/2023] [Accepted: 02/13/2023] [Indexed: 02/19/2023] Open
Abstract
The fruit fly-i.e., Drosophila melanogaster-has proven to be a very useful model for the understanding of basic physiological processes, such as development or ageing. The availability of straightforward genetic tools that can be used to produce engineered individuals makes this model extremely interesting for the understanding of the mechanisms underlying genetic diseases in physiological models. Mitochondrial diseases are a group of yet-incurable genetic disorders characterized by the malfunction of the oxidative phosphorylation system (OXPHOS), which is the highly conserved energy transformation system present in mitochondria. The generation of D. melanogaster models of mitochondrial disease started relatively recently but has already provided relevant information about the molecular mechanisms and pathological consequences of mitochondrial dysfunction. Here, we provide an overview of such models and highlight the relevance of D. melanogaster as a model to study mitochondrial disorders.
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Affiliation(s)
- Michele Brischigliaro
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy
- Veneto Institute of Molecular Medicine, 35129 Padova, Italy
| | - Erika Fernandez-Vizarra
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy
- Veneto Institute of Molecular Medicine, 35129 Padova, Italy
| | - Carlo Viscomi
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy
- Veneto Institute of Molecular Medicine, 35129 Padova, Italy
- Centre for the Study of Neurodegeneration (CESNE), University of Padova, 35131 Padova, Italy
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6
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Perivolidi VI, Violitzi F, Ioannidou E, Rinotas V, Stamatakis G, Samiotaki M, Panayotou G, Douni E. Proteomic Identification of the SLC25A46 Interactome in Transgenic Mice Expressing SLC25A46-FLAG. J Proteome Res 2022; 21:375-394. [PMID: 34983179 DOI: 10.1021/acs.jproteome.1c00728] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The outer mitochondrial membrane protein SLC25A46 has been recently identified as a novel genetic cause of a wide spectrum of neurological diseases. The aim of the present work was to elucidate the physiological role of SLC25A46 through the identification of its interactome with immunoprecipitation and proteomic analysis in whole cell extracts from the cerebellum, cerebrum, heart, and thymus of transgenic mice expressing ubiquitously SLC25A46-FLAG. Our analysis identified 371 novel putative interactors of SLC25A46 and confirmed 17 known ones. A total of 79 co-immunoprecipitated proteins were common in two or more tissues, mainly participating in mitochondrial activities such as oxidative phosphorylation (OXPHOS) and ATP production, active transport of ions or molecules, and the metabolism. Tissue-specific co-immunoprecipitated proteins were enriched for synapse annotated proteins in the cerebellum and cerebrum for metabolic processes in the heart and for nuclear processes and proteasome in the thymus. Our proteomic approach confirmed known mitochondrial interactors of SLC25A46 including MICOS complex subunits and also OPA1 and VDACs, while we identified novel interactors including the ADP/ATP translocases SLC25A4 and SLC25A5, subunits of the OXPHOS complexes and F1Fo-ATP synthase, and components of the mitochondria-ER contact sites. Our results show that SLC25A46 interacts with a large number of proteins and protein complexes involved in the mitochondria architecture, energy production, and flux and also in inter-organellar contacts.
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Affiliation(s)
- Vasiliki-Iris Perivolidi
- Laboratory of Genetics, Department of Biotechnology, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece.,Institute for Bioinnovation, Biomedical Sciences Research Center "Alexander Fleming", Fleming 34, 16672 Vari, Greece
| | - Foteini Violitzi
- Laboratory of Genetics, Department of Biotechnology, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece.,Institute for Bioinnovation, Biomedical Sciences Research Center "Alexander Fleming", Fleming 34, 16672 Vari, Greece
| | - Elisavet Ioannidou
- Institute for Bioinnovation, Biomedical Sciences Research Center "Alexander Fleming", Fleming 34, 16672 Vari, Greece
| | - Vagelis Rinotas
- Institute for Bioinnovation, Biomedical Sciences Research Center "Alexander Fleming", Fleming 34, 16672 Vari, Greece
| | - George Stamatakis
- Institute for Bioinnovation, Biomedical Sciences Research Center "Alexander Fleming", Fleming 34, 16672 Vari, Greece
| | - Martina Samiotaki
- Institute for Bioinnovation, Biomedical Sciences Research Center "Alexander Fleming", Fleming 34, 16672 Vari, Greece
| | - George Panayotou
- Institute for Bioinnovation, Biomedical Sciences Research Center "Alexander Fleming", Fleming 34, 16672 Vari, Greece
| | - Eleni Douni
- Laboratory of Genetics, Department of Biotechnology, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece.,Institute for Bioinnovation, Biomedical Sciences Research Center "Alexander Fleming", Fleming 34, 16672 Vari, Greece
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7
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Rouf MA, Wen L, Mahendra Y, Wang J, Zhang K, Liang S, Wang Y, Li Z, Wang Y, Wang G. The recent advances and future perspectives of genetic compensation studies in the zebrafish model. Genes Dis 2022; 10:468-479. [DOI: 10.1016/j.gendis.2021.12.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 11/08/2021] [Accepted: 12/01/2021] [Indexed: 10/19/2022] Open
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8
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Li Q, Madden JA, Lin J, Shi J, Rosen SM, Schmitz-Abe K, Agrawal PB. Reanalysis of Exome Data Identifies Novel SLC25A46 Variants Associated with Leigh Syndrome. J Pers Med 2021; 11:jpm11121277. [PMID: 34945750 PMCID: PMC8703603 DOI: 10.3390/jpm11121277] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 11/27/2021] [Accepted: 11/29/2021] [Indexed: 11/21/2022] Open
Abstract
SLC25A46 (solute carrier family 25 member 46) mutations have been linked to various neurological diseases with recessive inheritance, including Leigh syndrome, optic atrophy, and lethal congenital pontocerebellar hypoplasia. SLC25A46 is expressed in the outer membrane of mitochondria, where it plays a critical role in mitochondrial dynamics. A deceased 7-month-old female infant was suspected to have Leigh syndrome. Clinical exome sequencing was non-diagnostic, but research reanalysis of the sequencing data identified two novel variants in SLC25A46: a missense (c.1039C>T, p.Arg347Cys; NM_138773, hg19) and a donor splice region variant (c.283+5G>A) in intron 1. Both variants were predicted to be damaging. Sanger sequencing of cDNA detected a single missense allele in the patient compared to control, and the SLC25A46 transcript levels were also reduced due to the splice region variant. Additionally, Western blot analysis of whole-cell lysate showed a decrease of SLC25A46 expression in proband fibroblasts, relative to control cells. Further, analysis of mitochondrial morphology revealed evidence of increased fragmentation of the mitochondrial network in proband fibroblasts, compared to control cells. Collectively, our findings suggest that these novel variants in SLC24A46, the donor splice one and the missense variant, are the cause of the neurological phenotype in this proband.
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Affiliation(s)
- Qifei Li
- Division of Newborn Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Q.L.); (J.L.); (S.M.R.); (K.S.-A.)
- The Manton Center for Orphan Disease Research, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA;
- Division of Genetics and Genomics, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jill A. Madden
- The Manton Center for Orphan Disease Research, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA;
- Division of Genetics and Genomics, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jasmine Lin
- Division of Newborn Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Q.L.); (J.L.); (S.M.R.); (K.S.-A.)
- The Manton Center for Orphan Disease Research, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA;
- Division of Genetics and Genomics, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jiahai Shi
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong, China;
| | - Samantha M. Rosen
- Division of Newborn Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Q.L.); (J.L.); (S.M.R.); (K.S.-A.)
- The Manton Center for Orphan Disease Research, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA;
- Division of Genetics and Genomics, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Klaus Schmitz-Abe
- Division of Newborn Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Q.L.); (J.L.); (S.M.R.); (K.S.-A.)
- The Manton Center for Orphan Disease Research, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA;
| | - Pankaj B. Agrawal
- Division of Newborn Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Q.L.); (J.L.); (S.M.R.); (K.S.-A.)
- The Manton Center for Orphan Disease Research, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA;
- Division of Genetics and Genomics, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Correspondence: ; Tel.: +1-6179192153
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9
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Strachan EL, Mac White-Begg D, Crean J, Reynolds AL, Kennedy BN, O’Sullivan NC. The Role of Mitochondria in Optic Atrophy With Autosomal Inheritance. Front Neurosci 2021; 15:784987. [PMID: 34867178 PMCID: PMC8634724 DOI: 10.3389/fnins.2021.784987] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 10/22/2021] [Indexed: 11/13/2022] Open
Abstract
Optic atrophy (OA) with autosomal inheritance is a form of optic neuropathy characterized by the progressive and irreversible loss of vision. In some cases, this is accompanied by additional, typically neurological, extra-ocular symptoms. Underlying the loss of vision is the specific degeneration of the retinal ganglion cells (RGCs) which form the optic nerve. Whilst autosomal OA is genetically heterogenous, all currently identified causative genes appear to be associated with mitochondrial organization and function. However, it is unclear why RGCs are particularly vulnerable to mitochondrial aberration. Despite the relatively high prevalence of this disorder, there are currently no approved treatments. Combined with the lack of knowledge concerning the mechanisms through which aberrant mitochondrial function leads to RGC death, there remains a clear need for further research to identify the underlying mechanisms and develop treatments for this condition. This review summarizes the genes known to be causative of autosomal OA and the mitochondrial dysfunction caused by pathogenic mutations. Furthermore, we discuss the suitability of available in vivo models for autosomal OA with regards to both treatment development and furthering the understanding of autosomal OA pathology.
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Affiliation(s)
- Elin L. Strachan
- UCD Conway Institute, University College Dublin, Dublin, Ireland
- UCD School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Delphi Mac White-Begg
- UCD Conway Institute, University College Dublin, Dublin, Ireland
- UCD School of Veterinary Medicine, University College Dublin, Dublin, Ireland
| | - John Crean
- UCD Conway Institute, University College Dublin, Dublin, Ireland
- UCD School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
- UCD Diabetes Complications Research Centre, Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Alison L. Reynolds
- UCD Conway Institute, University College Dublin, Dublin, Ireland
- UCD School of Veterinary Medicine, University College Dublin, Dublin, Ireland
| | - Breandán N. Kennedy
- UCD Conway Institute, University College Dublin, Dublin, Ireland
- UCD School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Niamh C. O’Sullivan
- UCD Conway Institute, University College Dublin, Dublin, Ireland
- UCD School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
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10
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Gao L, Wang M, Liao L, Gou N, Xu P, Ren Z, Yao M, Yuan E, Yang X, Ren J. A Slc25a46 Mouse Model Simulating Age-Associated Motor Deficit, Redox Imbalance, and Mitochondria Dysfunction. J Gerontol A Biol Sci Med Sci 2021; 76:440-447. [PMID: 33277645 DOI: 10.1093/gerona/glaa306] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Indexed: 01/10/2023] Open
Abstract
The mitochondrial theory of aging postulates that accumulation of mtDNA mutations and mitochondrial dysfunction are responsible for producing aging phenotypes. To more comprehensively explore the complex relationship between aging and mitochondria dysfunction, we have developed a mouse model with Slc25a46 knockout, a nuclear gene described as encoding mitochondrial carriers, by CRISPR/Cas9 gene editing to mimic some typical aging phenotypes in human. Slc25a46-/- mice present segmental premature aging phenotypes characterized by shortened life span of no more than 2 months, obviously defective motor ability, gastrocnemius muscle atrophy, and imbalance of redox level in brain and liver. The underlying mechanism for multiple organ disorder may attribute to mitochondrial dysfunction, which is mainly manifested in the damaged mitochondrial structure (eg, vacuolar structure, irregular swelling, and disorganized cristae) and an age-associated decrease in respiratory chain enzyme (mainly complex I and IV) activity. In summary, our study suggests that the Slc25a46-/- mouse is a valid animal model for segmental aging-related pathologies studies based on mitochondrial theory, generating a new platform to both understand mechanisms between aging and mitochondria dysfunction as well as to design mitochondria-based therapeutic strategies to improve mitochondrial quality, and thereby the overall healthspan.
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Affiliation(s)
- Li Gao
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Min Wang
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Linfeng Liao
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Na Gou
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Piao Xu
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Zhengyu Ren
- School of Pharmaceutical Science, University of South China, Hengyang, China
| | - Maojin Yao
- Guangzhou Institute of Respiratory Disease & China State Key Laboratory of Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, China
| | - Erdong Yuan
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Xinquan Yang
- School of Life Sciences, Guangzhou University, China
| | - Jiaoyan Ren
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China
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11
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Hemel IMGM, Engelen BPH, Luber N, Gerards M. A hitchhiker's guide to mitochondrial quantification. Mitochondrion 2021; 59:216-224. [PMID: 34102326 DOI: 10.1016/j.mito.2021.06.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 05/21/2021] [Accepted: 06/03/2021] [Indexed: 12/31/2022]
Abstract
The variety of available mitochondrial quantification tools makes it difficult to select the most reliable and accurate quantification tool. Here, we performed elaborate analyses on five open source ImageJ tools. Excessive clustering of mitochondrial structures was observed in four tools, caused by the global thresholding applied by these tools. The Mitochondrial Analyzer, which uses adaptive thresholding, outperformed the other examined tools, with accurate structural segregation and identification. Additionally, we showed that the Mitochondrial Analyzer successfully identifies mitochondrial morphology differences. Based on the observed performance, we consider the Mitochondrial Analyzer the best open source tool for mitochondrial network morphology quantification.
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Affiliation(s)
- Irene M G M Hemel
- Maastricht Centre for Systems Biology (MaCSBio), Maastricht University, Maastricht, the Netherlands
| | - Bob P H Engelen
- Maastricht Centre for Systems Biology (MaCSBio), Maastricht University, Maastricht, the Netherlands
| | - Nicole Luber
- Maastricht Centre for Systems Biology (MaCSBio), Maastricht University, Maastricht, the Netherlands
| | - Mike Gerards
- Maastricht Centre for Systems Biology (MaCSBio), Maastricht University, Maastricht, the Netherlands.
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12
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Yang L, Slone J, Li Z, Lou X, Hu YC, Queme LF, Jankowski MP, Huang T. Systemic administration of AAV-Slc25a46 mitigates mitochondrial neuropathy in Slc25a46-/- mice. Hum Mol Genet 2021; 29:649-661. [PMID: 31943007 DOI: 10.1093/hmg/ddz277] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 11/10/2019] [Accepted: 11/11/2019] [Indexed: 12/20/2022] Open
Abstract
Mitochondrial disorders are the result of nuclear and mitochondrial DNA mutations that affect multiple organs, with the central and peripheral nervous system often affected. Currently, there is no cure for mitochondrial disorders. Currently, gene therapy offers a novel approach for treating monogenetic disorders, including nuclear genes associated with mitochondrial disorders. We utilized a mouse model carrying a knockout of the mitochondrial fusion-fission-related gene solute carrier family 25 member 46 (Slc25a46) and treated them with neurotrophic AAV-PHP.B vector carrying the mouse Slc25a46 coding sequence. Thereafter, we used immunofluorescence staining and western blot to test the transduction efficiency of this vector. Toluidine blue staining and electronic microscopy were utilized to assess the morphology of optic and sciatic nerves following treatment, and the morphology and respiratory chain activity of mitochondria within these tissues were determined as well. The adeno-associated virus (AAV) vector effectively transduced in the cerebrum, cerebellum, heart, liver and sciatic nerves. AAV-Slc25a46 treatment was able to rescue the premature death in the mutant mice (Slc25a46-/-). The treatment-improved electronic conductivity of the peripheral nerves increased mobility and restored mitochondrial complex activities. Most notably, mitochondrial morphology inside the tissues of both the central and peripheral nervous systems was normalized, and the neurodegeneration, chronic neuroinflammation and loss of Purkinje cell dendrites observed within the mutant mice were alleviated. Overall, our study shows that AAV-PHP.B's neurotrophic properties are plausible for treating conditions where the central nervous system is affected, such as many mitochondrial diseases, and that AAV-Slc25a46 could be a novel approach for treating SLC25A46-related mitochondrial disorders.
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Affiliation(s)
- Li Yang
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.,Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Jesse Slone
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Zhuo Li
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.,State Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan 410078, China
| | - Xiaoting Lou
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.,School of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Yueh-Chiang Hu
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Luis F Queme
- Division of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Michael P Jankowski
- Division of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Taosheng Huang
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
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13
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Zou W, Chen Q, Slone J, Yang L, Lou X, Diao J, Huang T. Nanoscopic quantification of sub-mitochondrial morphology, mitophagy and mitochondrial dynamics in living cells derived from patients with mitochondrial diseases. J Nanobiotechnology 2021; 19:136. [PMID: 33985528 PMCID: PMC8120746 DOI: 10.1186/s12951-021-00882-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 05/05/2021] [Indexed: 11/13/2022] Open
Abstract
SLC25A46 mutations have been found to lead to mitochondrial hyper-fusion and reduced mitochondrial respiratory function, which results in optic atrophy, cerebellar atrophy, and other clinical symptoms of mitochondrial disease. However, it is generally believed that mitochondrial fusion is attributable to increased mitochondrial oxidative phosphorylation (OXPHOS), which is inconsistent with the decreased OXPHOS of highly-fused mitochondria observed in previous studies. In this paper, we have used the live-cell nanoscope to observe and quantify the structure of mitochondrial cristae, and the behavior of mitochondria and lysosomes in patient-derived SLC25A46 mutant fibroblasts. The results show that the cristae have been markedly damaged in the mutant fibroblasts, but there is no corresponding increase in mitophagy. This study suggests that severely damaged mitochondrial cristae might be the predominant cause of reduced OXPHOS in SLC25A46 mutant fibroblasts. This study demonstrates the utility of nanoscope-based imaging for realizing the sub-mitochondrial morphology, mitophagy and mitochondrial dynamics in living cells, which may be particularly valuable for the quick evaluation of pathogenesis of mitochondrial morphological abnormalities. ![]()
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Affiliation(s)
- Weiwei Zou
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA.,Department of Obstetrics and Gynecology, Reproductive Medicine Center, The First Affiliated Hospital of Anhui Medical University, Hefei, 230022, China
| | - Qixin Chen
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA.,Institute of Materia Medica, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, 250062, China
| | - Jesse Slone
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA.,Department of Pediatrics, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, 14203, USA
| | - Li Yang
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA.,Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Xiaoting Lou
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA.,School of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Jiajie Diao
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA.
| | - Taosheng Huang
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA. .,Department of Pediatrics, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, 14203, USA.
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14
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Raju S, Medarametla S, Boraiah N. Dystonia and Hereditary Motor Sensory Neuropathy 6B Due to SLC25A46 Gene Mutations. Mov Disord Clin Pract 2021; 8:480-482. [PMID: 33816684 DOI: 10.1002/mdc3.13139] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 12/01/2020] [Accepted: 12/05/2020] [Indexed: 11/06/2022] Open
Affiliation(s)
- Srinivas Raju
- Department of Neurology Vydehi Institute of Medical Sciences & Research Centre Bangalore India.,Department of Neurology Bangalore Baptist Hospital Bangalore India.,Department of Neurology Columbia Asia Hebbal Bangalore India
| | - Soumya Medarametla
- Department of Neurology Vydehi Institute of Medical Sciences & Research Centre Bangalore India
| | - Nataraju Boraiah
- Department of Neurology Vydehi Institute of Medical Sciences & Research Centre Bangalore India
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15
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Sharma G, Pfeffer G, Shutt TE. Genetic Neuropathy Due to Impairments in Mitochondrial Dynamics. BIOLOGY 2021; 10:268. [PMID: 33810506 PMCID: PMC8066130 DOI: 10.3390/biology10040268] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 03/19/2021] [Accepted: 03/21/2021] [Indexed: 12/12/2022]
Abstract
Mitochondria are dynamic organelles capable of fusing, dividing, and moving about the cell. These properties are especially important in neurons, which in addition to high energy demand, have unique morphological properties with long axons. Notably, mitochondrial dysfunction causes a variety of neurological disorders including peripheral neuropathy, which is linked to impaired mitochondrial dynamics. Nonetheless, exactly why peripheral neurons are especially sensitive to impaired mitochondrial dynamics remains somewhat enigmatic. Although the prevailing view is that longer peripheral nerves are more sensitive to the loss of mitochondrial motility, this explanation is insufficient. Here, we review pathogenic variants in proteins mediating mitochondrial fusion, fission and transport that cause peripheral neuropathy. In addition to highlighting other dynamic processes that are impacted in peripheral neuropathies, we focus on impaired mitochondrial quality control as a potential unifying theme for why mitochondrial dysfunction and impairments in mitochondrial dynamics in particular cause peripheral neuropathy.
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Affiliation(s)
- Govinda Sharma
- Departments of Medical Genetics and Biochemistry & Molecular Biology, Cumming School of Medicine, Alberta Children’s Hospital Research Institute, Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada;
| | - Gerald Pfeffer
- Departments of Clinical Neurosciences and Medical Genetics, Cumming School of Medicine, Hotchkiss Brain Institute, Alberta Child Health Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada;
| | - Timothy E. Shutt
- Departments of Medical Genetics and Biochemistry & Molecular Biology, Cumming School of Medicine, Alberta Children’s Hospital Research Institute, Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada;
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16
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Ali MS, Suda K, Kowada R, Ueoka I, Yoshida H, Yamaguchi M. Neuron-specific knockdown of solute carrier protein SLC25A46a induces locomotive defects, an abnormal neuron terminal morphology, learning disability, and shortened lifespan. IBRO Rep 2020; 8:65-75. [PMID: 32140609 PMCID: PMC7047145 DOI: 10.1016/j.ibror.2020.02.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 02/17/2020] [Indexed: 01/21/2023] Open
Abstract
Various mutations in the SLC25A46 gene have been reported in mitochondrial diseases that are sometimes classified as type 2 Charcot-Marie-Tooth disease, optic atrophy, and Leigh syndrome. Although human SLC25A46 is a well-known transporter that acts through the mitochondrial outer membrane, the relationship between neurodegeneration in these diseases and the loss-of-function of SLC25A46 remains unclear. Two Drosophila genes, CG8931 (dSLC25A46a) and CG5755 (dSLC25A46b) have been identified as candidate homologs of human SLC25A46. We previously characterized the phenotypes of pan-neuron-specific dSLC25A46b knockdown flies. In the present study, we developed pan-neuron-specific dSLC25A46a knockdown flies and examined their phenotypes. Neuron-specific dSLC25A46a knockdown resulted in reduced mobility in larvae as well as adults. An aberrant morphology for neuromuscular junctions (NMJs), such as a reduced synaptic branch length and decreased number and size of boutons, was observed in dSLC25A46a knockdown flies. Learning ability was also reduced in the larvae of knockdown flies. In dSLC25A46a knockdown flies, mitochondrial hyperfusion was detected in NMJ synapses together with the accumulation of reactive oxygen species and reductions in ATP. These phenotypes were very similar to those of dSLC25A46b knockdown flies, suggesting that dSLC25A46a and dSLC25A46b do not have redundant roles in neurons. Collectively, these results show that the depletion of SLC25A46a leads to mitochondrial defects followed by an aberrant synaptic morphology, resulting in locomotive defects and learning disability. Thus, the dSLC25A46a knockdown fly summarizes most of the phenotypes in patients with mitochondrial diseases, offering a useful tool for studying these diseases.
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Affiliation(s)
- Md Saheb Ali
- Department of Applied Biology, Advanced Insect Research Promotion Center, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan
- Faculty of Agriculture, Bangladesh Jute Research Institute, Manik Mia Ave., Dhaka, 1207, Bangladesh
| | - Kojiro Suda
- Department of Applied Biology, Advanced Insect Research Promotion Center, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan
| | - Ryosuke Kowada
- Department of Applied Biology, Advanced Insect Research Promotion Center, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan
| | - Ibuki Ueoka
- Department of Applied Biology, Advanced Insect Research Promotion Center, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan
| | - Hideki Yoshida
- Department of Applied Biology, Advanced Insect Research Promotion Center, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan
| | - Masamitsu Yamaguchi
- Department of Applied Biology, Advanced Insect Research Promotion Center, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan
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17
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Palmieri F, Scarcia P, Monné M. Diseases Caused by Mutations in Mitochondrial Carrier Genes SLC25: A Review. Biomolecules 2020; 10:biom10040655. [PMID: 32340404 PMCID: PMC7226361 DOI: 10.3390/biom10040655] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 04/15/2020] [Accepted: 04/17/2020] [Indexed: 12/13/2022] Open
Abstract
In the 1980s, after the mitochondrial DNA (mtDNA) had been sequenced, several diseases resulting from mtDNA mutations emerged. Later, numerous disorders caused by mutations in the nuclear genes encoding mitochondrial proteins were found. A group of these diseases are due to defects of mitochondrial carriers, a family of proteins named solute carrier family 25 (SLC25), that transport a variety of solutes such as the reagents of ATP synthase (ATP, ADP, and phosphate), tricarboxylic acid cycle intermediates, cofactors, amino acids, and carnitine esters of fatty acids. The disease-causing mutations disclosed in mitochondrial carriers range from point mutations, which are often localized in the substrate translocation pore of the carrier, to large deletions and insertions. The biochemical consequences of deficient transport are the compartmentalized accumulation of the substrates and dysfunctional mitochondrial and cellular metabolism, which frequently develop into various forms of myopathy, encephalopathy, or neuropathy. Examples of diseases, due to mitochondrial carrier mutations are: combined D-2- and L-2-hydroxyglutaric aciduria, carnitine-acylcarnitine carrier deficiency, hyperornithinemia-hyperammonemia-homocitrillinuria (HHH) syndrome, early infantile epileptic encephalopathy type 3, Amish microcephaly, aspartate/glutamate isoform 1 deficiency, congenital sideroblastic anemia, Fontaine progeroid syndrome, and citrullinemia type II. Here, we review all the mitochondrial carrier-related diseases known until now, focusing on the connections between the molecular basis, altered metabolism, and phenotypes of these inherited disorders.
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Affiliation(s)
- Ferdinando Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology, University of Bari Aldo Moro, via E. Orabona 4, 70125 Bari, Italy;
- Correspondence: (F.P.); (M.M.); Tel.: +39-0805443323 (F.P.)
| | - Pasquale Scarcia
- Department of Biosciences, Biotechnologies and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology, University of Bari Aldo Moro, via E. Orabona 4, 70125 Bari, Italy;
| | - Magnus Monné
- Department of Biosciences, Biotechnologies and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology, University of Bari Aldo Moro, via E. Orabona 4, 70125 Bari, Italy;
- Department of Sciences, University of Basilicata, via Ateneo Lucano 10, 85100 Potenza, Italy
- Correspondence: (F.P.); (M.M.); Tel.: +39-0805443323 (F.P.)
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18
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Genetic compensation in a stable slc25a46 mutant zebrafish: A case for using F0 CRISPR mutagenesis to study phenotypes caused by inherited disease. PLoS One 2020; 15:e0230566. [PMID: 32208444 PMCID: PMC7092968 DOI: 10.1371/journal.pone.0230566] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 03/03/2020] [Indexed: 12/22/2022] Open
Abstract
A phenomenon of genetic compensation is commonly observed when an organism with a disease-bearing mutation shows incomplete penetrance of the disease phenotype. Such incomplete phenotypic penetrance, or genetic compensation, is more commonly found in stable knockout models, rather than transient knockdown models. As such, these incidents present a challenge for the disease modeling field, although a deeper understanding of genetic compensation may also hold the key for novel therapeutic interventions. In our study we created a knockout model of slc25a46 gene, which is a recently discovered important player in mitochondrial dynamics, and deleterious mutations in which are known to cause peripheral neuropathy, optic atrophy and cerebellar ataxia. We report a case of genetic compensation in a stable slc25a46 homozygous zebrafish mutant (hereafter referred as “mutant”), in contrast to a penetrant disease phenotype in the first generation (F0) slc25a46 mosaic mutant (hereafter referred as “crispant”), generated with CRISPR/Cas-9 technology. We show that the crispant phenotype is specific and rescuable. By performing mRNA sequencing, we define significant changes in slc25a46 mutant’s gene expression profile, which are largely absent in crispants. We find that among the most significantly altered mRNAs, anxa6 gene stands out as a functionally relevant player in mitochondrial dynamics. We also find that our genetic compensation case does not arise from mechanisms driven by mutant mRNA decay. Our study contributes to the growing evidence of the genetic compensation phenomenon and presents novel insights about Slc25a46 function. Furthermore, our study provides the evidence for the efficiency of F0 CRISPR screens for disease candidate genes, which may be used to advance the field of functional genetics.
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19
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van Dijk T, Rudnik-Schöneborn S, Senderek J, Hajmousa G, Mei H, Dusl M, Aronica E, Barth P, Baas F. Pontocerebellar hypoplasia with spinal muscular atrophy (PCH1): identification of SLC25A46 mutations in the original Dutch PCH1 family. Brain 2019. [PMID: 28637197 DOI: 10.1093/brain/awx147] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Tessa van Dijk
- Department of Clinical Genetics, Academic Medical Center, Amsterdam, The Netherlands
| | - Sabine Rudnik-Schöneborn
- Division of Human Genetics, Medical University Innsbruck, Innsbruck, Austria.,Institute of Human Genetics, RWTH Aachen University, Aachen, Germany
| | - Jan Senderek
- Friedrich-Baur-Institute, Department of Neurology, Ludwig-Maximilians-University, Munich, Germany
| | - Ghazaleh Hajmousa
- Department of Clinical Genetics, Academic Medical Center, Amsterdam, The Netherlands
| | - Hailiang Mei
- Sequencing Analysis Support Core, Leiden University Medical Center, Leiden, The Netherlands
| | - Marina Dusl
- Friedrich-Baur-Institute, Department of Neurology, Ludwig-Maximilians-University, Munich, Germany
| | - Eleonora Aronica
- Department of (Neuro) Pathology, Academic Medical Center, Amsterdam, The Netherlands
| | - Peter Barth
- Department of Pediatric Neurology, Academic Medical Center, Amsterdam, The Netherlands
| | - Frank Baas
- Department of Clinical Genetics, Academic Medical Center, Amsterdam, The Netherlands.,Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
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20
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Theunissen TEJ, Nguyen M, Kamps R, Hendrickx AT, Sallevelt SCEH, Gottschalk RWH, Calis CM, Stassen APM, de Koning B, Mulder-Den Hartog ENM, Schoonderwoerd K, Fuchs SA, Hilhorst-Hofstee Y, de Visser M, Vanoevelen J, Szklarczyk R, Gerards M, de Coo IFM, Hellebrekers DMEI, Smeets HJM. Whole Exome Sequencing Is the Preferred Strategy to Identify the Genetic Defect in Patients With a Probable or Possible Mitochondrial Cause. Front Genet 2018; 9:400. [PMID: 30369941 PMCID: PMC6194163 DOI: 10.3389/fgene.2018.00400] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 09/03/2018] [Indexed: 01/03/2023] Open
Abstract
Mitochondrial disorders, characterized by clinical symptoms and/or OXPHOS deficiencies, are caused by pathogenic variants in mitochondrial genes. However, pathogenic variants in some of these genes can lead to clinical manifestations which overlap with other neuromuscular diseases, which can be caused by pathogenic variants in non-mitochondrial genes as well. Mitochondrial pathogenic variants can be found in the mitochondrial DNA (mtDNA) or in any of the 1,500 nuclear genes with a mitochondrial function. We have performed a two-step next-generation sequencing approach in a cohort of 117 patients, mostly children, in whom a mitochondrial disease-cause could likely or possibly explain the phenotype. A total of 86 patients had a mitochondrial disorder, according to established clinical and biochemical criteria. The other 31 patients had neuromuscular symptoms, where in a minority a mitochondrial genetic cause is present, but a non-mitochondrial genetic cause is more likely. All patients were screened for pathogenic variants in the mtDNA and, if excluded, analyzed by whole exome sequencing (WES). Variants were filtered for being pathogenic and compatible with an autosomal or X-linked recessive mode of inheritance in families with multiple affected siblings and/or consanguineous parents. Non-consanguineous families with a single patient were additionally screened for autosomal and X-linked dominant mutations in a predefined gene-set. We identified causative pathogenic variants in the mtDNA in 20% of the patient-cohort, and in nuclear genes in 49%, implying an overall yield of 68%. We identified pathogenic variants in mitochondrial and non-mitochondrial genes in both groups with, obviously, a higher number of mitochondrial genes affected in mitochondrial disease patients. Furthermore, we show that 31% of the disease-causing genes in the mitochondrial patient group were not included in the MitoCarta database, and therefore would have been missed with MitoCarta based gene-panels. We conclude that WES is preferable to panel-based approaches for both groups of patients, as the mitochondrial gene-list is not complete and mitochondrial symptoms can be secondary. Also, clinically and genetically heterogeneous disorders would require sequential use of multiple different gene panels. We conclude that WES is a comprehensive and unbiased approach to establish a genetic diagnosis in these patients, able to resolve multi-genic disease-causes.
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Affiliation(s)
- Tom E J Theunissen
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, Netherlands.,Research Institute GROW, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Minh Nguyen
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, Netherlands.,Research Institute GROW, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Rick Kamps
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Alexandra T Hendrickx
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Suzanne C E H Sallevelt
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Ralph W H Gottschalk
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Chantal M Calis
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Alphons P M Stassen
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Bart de Koning
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, Netherlands
| | | | | | - Sabine A Fuchs
- Department of Metabolic Disorders, University Medical Centre Utrecht, Utrecht, Netherlands
| | | | - Marianne de Visser
- Department of Neurology, Academic Medical Centre Amsterdam, Amsterdam, Netherlands
| | - Jo Vanoevelen
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Radek Szklarczyk
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, Netherlands.,Research Institute GROW, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Mike Gerards
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, Netherlands.,Maastricht Center for Systems Biology (MaCSBio), Maastricht University Medical Centre, Maastricht, Netherlands
| | - Irenaeus F M de Coo
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, Netherlands.,Department of Pediatric Neurology, Erasmus MC Sophia Children's Hospital, Rotterdam, Netherlands
| | - Debby M E I Hellebrekers
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Hubert J M Smeets
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, Netherlands.,Research Institute GROW, Maastricht University Medical Centre, Maastricht, Netherlands
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21
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Abrams AJ, Fontanesi F, Tan NBL, Buglo E, Campeanu IJ, Rebelo AP, Kornberg AJ, Phelan DG, Stark Z, Zuchner S. Insights into the genotype-phenotype correlation and molecular function of SLC25A46. Hum Mutat 2018; 39:1995-2007. [PMID: 30178502 DOI: 10.1002/humu.23639] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 08/29/2018] [Accepted: 08/30/2018] [Indexed: 01/08/2023]
Abstract
Recessive SLC25A46 mutations cause a spectrum of neurodegenerative disorders with optic atrophy as a core feature. We report a patient with optic atrophy, peripheral neuropathy, ataxia, but not cerebellar atrophy, who is on the mildest end of the phenotypic spectrum. By studying seven different nontruncating mutations, we found that the stability of the SLC25A46 protein inversely correlates with the severity of the disease and the patient's variant does not markedly destabilize the protein. SLC25A46 belongs to the mitochondrial transporter family, but it is not known to have transport function. Apart from this possible function, SLC25A46 forms molecular complexes with proteins involved in mitochondrial dynamics and cristae remodeling. We demonstrate that the patient's mutation directly affects the SLC25A46 interaction with MIC60. Furthermore, we mapped all of the reported substitutions in the protein onto a 3D model and found that half of them fall outside of the signature carrier motifs associated with transport function. We thus suggest that there are two distinct molecular mechanisms in SLC25A46-associated pathogenesis, one that destabilizes the protein while the other alters the molecular interactions of the protein. These results have the potential to inform clinical prognosis of such patients and indicate a pathway to drug target development.
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Affiliation(s)
- Alexander J Abrams
- John P. Hussman Institute for Human Genomics, Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami, Miami, Florida, USA
| | - Flavia Fontanesi
- Department of Biochemistry and Molecular Biology, University of Miami, Miami, Florida, USA
| | - Natalie B L Tan
- Victorian Clinical Genetics Services, Murdoch Childrens Research Institute, Melbourne, Australia
| | - Elena Buglo
- John P. Hussman Institute for Human Genomics, Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami, Miami, Florida, USA
| | - Ion J Campeanu
- Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Adriana P Rebelo
- John P. Hussman Institute for Human Genomics, Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami, Miami, Florida, USA
| | - Andrew J Kornberg
- Department of Neurology, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Dean G Phelan
- Victorian Clinical Genetics Services, Murdoch Childrens Research Institute, Melbourne, Australia
| | - Zornitza Stark
- Victorian Clinical Genetics Services, Murdoch Childrens Research Institute, Melbourne, Australia
| | - Stephan Zuchner
- John P. Hussman Institute for Human Genomics, Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami, Miami, Florida, USA
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22
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Finsterer J, Zarrouk-Mahjoub S. Cerebellar atrophy is common among mitochondrial disorders. Metab Brain Dis 2018; 33:987-988. [PMID: 29717375 DOI: 10.1007/s11011-018-0238-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Accepted: 04/13/2018] [Indexed: 12/14/2022]
Affiliation(s)
- Josef Finsterer
- Krankenanstalt Rudolfstiftung, Postfach 20, 1180, Vienna, Austria.
| | - Sinda Zarrouk-Mahjoub
- Pasteur Institute of Tunis, University of Tunis El Manar and Genomics Platform, Tunis, Tunisia
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23
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Gerards M, Cannino G, González de Cózar JM, Jacobs HT. Intracellular vesicle trafficking plays an essential role in mitochondrial quality control. Mol Biol Cell 2018; 29:809-819. [PMID: 29343549 PMCID: PMC5905294 DOI: 10.1091/mbc.e17-10-0619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The Drosophila gene products Bet1, Slh, and CG10144, predicted to function in intracellular vesicle trafficking, were previously found to be essential for mitochondrial nucleoid maintenance. Here we show that Slh and Bet1 cooperate to maintain mitochondrial functions. In their absence, mitochondrial content, membrane potential, and respiration became abnormal, accompanied by mitochondrial proteotoxic stress, but without direct effects on mtDNA. Immunocytochemistry showed that both Slh and Bet1 are localized at the Golgi, together with a proportion of Rab5-positive vesicles. Some Bet1, as well as a tiny amount of Slh, cofractionated with highly purified mitochondria, while live-cell imaging showed coincidence of fluorescently tagged Bet1 with most Lysotracker-positive and a small proportion of Mitotracker-positive structures. This three-way association was disrupted in cells knocked down for Slh, although colocalized lysosomal and mitochondrial signals were still seen. Neither Slh nor Bet1 was required for global mitophagy or endocytosis, but prolonged Slh knockdown resulted in G2 growth arrest, with increased cell diameter. These effects were shared with knockdown of betaCOP but not of CG1044, Snap24, or Syntaxin6. Our findings implicate vesicle sorting at the cis-Golgi in mitochondrial quality control.
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Affiliation(s)
- Mike Gerards
- Faculty of Medicine and Life Sciences and Tampere University Hospital, FI-33014 University of Tampere, Finland.,Maastricht Center for Systems Biology (MaCSBio), Maastricht University, 6229 ER Maastricht, The Netherlands
| | - Giuseppe Cannino
- Faculty of Medicine and Life Sciences and Tampere University Hospital, FI-33014 University of Tampere, Finland
| | - Jose M González de Cózar
- Faculty of Medicine and Life Sciences and Tampere University Hospital, FI-33014 University of Tampere, Finland
| | - Howard T Jacobs
- Faculty of Medicine and Life Sciences and Tampere University Hospital, FI-33014 University of Tampere, Finland.,Institute of Biotechnology, FI-00014 University of Helsinki, Finland
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24
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Novel Drosophila model for mitochondrial diseases by targeting of a solute carrier protein SLC25A46. Brain Res 2018; 1689:30-44. [PMID: 29604258 DOI: 10.1016/j.brainres.2018.03.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 03/21/2018] [Accepted: 03/23/2018] [Indexed: 01/26/2023]
Abstract
Mutations in SLC25A46 gene have been identified in mitochondrial diseases that are sometimes classified as Charcot-Marie-Tooth disease type 2, optic atrophy and Leigh syndrome. Human SLC25A46 functions as a transporter across the outer mitochondrial membrane. However, it is still unknown how the neurodegeneration occurring in these diseases relates to the loss of SLC25A46 function. Drosophila has CG5755 (dSLC25A46) as a single human SLC25A46 homolog. Here we established pan-neuron specific dSLC25A46 knockdown flies, and examined their phenotypes. Neuron specific knockdown of dSLC25A46 resulted in an impaired motility in both larvae and adults. Defects at neuromuscular junctions (NMJs), such as reduced synaptic branch length, decreased number and size of bouton, reduced density and size of active zone were also observed with the dSLC25A46 knockdown flies. Mitochondrial hyperfusion in synapse at NMJ, accumulation of reactive oxygen species and reduction of ATP were also observed in the dSLC25A46 knockdown flies. These results indicate that depletion of SLC25A46 induces mitochondrial defects accompanied with aberrant morphology of motoneuron and reduction of active zone that results in defect in locomotive ability. In addition, it is known that SLC25A46 mutations in human cause optic atrophy and knockdown of dSLC25A46 induces aberrant morphology of optic stalk of photoreceptor neurons in third instar larvae. Morphology and development of optic stalk of photoreceptor neurons in Drosophila are precisely regulated via cell proliferation and migration. Immunocytochemical analyses of subcellular localization of dSLC25A46 revealed that dSLC25A46 localizes not only in mitochondria, but also in plasma membrane. These observations suggest that in addition to the role in mitochondrial function, plasma membrane-localized dSLC25A46 plays a role in cell proliferation and/or migration to control optic stalk formation. The dSLC25A46 knockdown fly thus recapitulates most of the phenotypes in mitochondrial disease patients, providing a useful tool to study these diseases.
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25
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Li Z, Peng Y, Hufnagel RB, Hu YC, Zhao C, Queme LF, Khuchua Z, Driver AM, Dong F, Lu QR, Lindquist DM, Jankowski MP, Stottmann RW, Kao WWY, Huang T. Loss of SLC25A46 causes neurodegeneration by affecting mitochondrial dynamics and energy production in mice. Hum Mol Genet 2018; 26:3776-3791. [PMID: 28934388 DOI: 10.1093/hmg/ddx262] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 06/23/2017] [Indexed: 11/13/2022] Open
Abstract
Recently, we identified biallelic mutations of SLC25A46 in patients with multiple neuropathies. Functional studies revealed that SLC25A46 may play an important role in mitochondrial dynamics by mediating mitochondrial fission. However, the cellular basis and pathogenic mechanism of the SLC25A46-related neuropathies are not fully understood. Thus, we generated a Slc25a46 knock-out mouse model. Mice lacking SLC25A46 displayed severe ataxia, mainly caused by degeneration of Purkinje cells. Increased numbers of small, unmyelinated and degenerated optic nerves as well as loss of retinal ganglion cells indicated optic atrophy. Compound muscle action potentials in peripheral nerves showed peripheral neuropathy associated with degeneration and demyelination in axons. Mutant cerebellar neurons have large mitochondria, which exhibit abnormal distribution and transport. Biochemically mutant mice showed impaired electron transport chain activity and accumulated autophagy markers. Our results suggest that loss of SLC25A46 causes degeneration in neurons by affecting mitochondrial dynamics and energy production.
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Affiliation(s)
- Zhuo Li
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.,State Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan 410078, China
| | - Yanyan Peng
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Robert B Hufnagel
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | | | - Chuntao Zhao
- Division of Experimental Hematology and Cancer Biology, Brain Tumor Center, Cancer and Blood Diseases Institute
| | | | - Zaza Khuchua
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Ashley M Driver
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Fei Dong
- Department of Ophthalmology, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Q Richard Lu
- Division of Experimental Hematology and Cancer Biology, Brain Tumor Center, Cancer and Blood Diseases Institute
| | - Diana M Lindquist
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | | | - Rolf W Stottmann
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Winston W Y Kao
- Department of Ophthalmology, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Taosheng Huang
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
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26
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Wan J, Steffen J, Yourshaw M, Mamsa H, Andersen E, Rudnik-Schöneborn S, Pope K, Howell KB, McLean CA, Kornberg AJ, Joseph J, Lockhart PJ, Zerres K, Ryan MM, Nelson SF, Koehler CM, Jen JC. Loss of function of SLC25A46 causes lethal congenital pontocerebellar hypoplasia. Brain 2017; 139:2877-2890. [PMID: 27543974 DOI: 10.1093/brain/aww212] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 07/01/2016] [Indexed: 01/17/2023] Open
Abstract
Disturbed mitochondrial fusion and fission have been linked to various neurodegenerative disorders. In siblings from two unrelated families who died soon after birth with a profound neurodevelopmental disorder characterized by pontocerebellar hypoplasia and apnoea, we discovered a missense mutation and an exonic deletion in the SLC25A46 gene encoding a mitochondrial protein recently implicated in optic atrophy spectrum disorder. We performed functional studies that confirmed the mitochondrial localization and pro-fission properties of SLC25A46. Knockdown of slc24a46 expression in zebrafish embryos caused brain malformation, spinal motor neuron loss, and poor motility. At the cellular level, we observed abnormally elongated mitochondria, which was rescued by co-injection of the wild-type but not the mutant slc25a46 mRNA. Conversely, overexpression of the wild-type protein led to mitochondrial fragmentation and disruption of the mitochondrial network. In contrast to mutations causing non-lethal optic atrophy, missense mutations causing lethal congenital pontocerebellar hypoplasia markedly destabilize the protein. Indeed, the clinical severity appears inversely correlated with the relative stability of the mutant protein. This genotype-phenotype correlation underscores the importance of SLC25A46 and fine tuning of mitochondrial fission and fusion in pontocerebellar hypoplasia and central neurodevelopment in addition to optic and peripheral neuropathy across the life span.
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Affiliation(s)
- Jijun Wan
- Department of Neurology, University of California, Los Angeles, CA, USA
| | - Janos Steffen
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - Michael Yourshaw
- Department of Human Genetics, University of California, Los Angeles, CA, USA
| | - Hafsa Mamsa
- Department of Neurology, University of California, Los Angeles, CA, USA
| | - Erik Andersen
- Royal Children's Hospital, Murdoch Children's Research Institute, University of Melbourne, Melbourne, Victoria, Australia
| | | | - Kate Pope
- Royal Children's Hospital, Murdoch Children's Research Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Katherine B Howell
- Royal Children's Hospital, Murdoch Children's Research Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Catriona A McLean
- Anatomical Pathology, The Alfred Hospital; Howard Florey Neuroscience Institute, Melbourne, Victoria, Australia
| | - Andrew J Kornberg
- Royal Children's Hospital, Murdoch Children's Research Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Jörg Joseph
- Department of Neonatology, Bürgerhospital Frankfurt am Main, Germany
| | - Paul J Lockhart
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia.,Department of Paediatrics, The University of Melbourne, Parkville, Victoria, Australia
| | - Klaus Zerres
- Institut für Humangenetik der RWTH Aachen, Aachen, Germany
| | - Monique M Ryan
- Royal Children's Hospital, Murdoch Children's Research Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Stanley F Nelson
- Department of Human Genetics, University of California, Los Angeles, CA, USA.,Department of Pathology and Laboratory Medicine, University of California, Los Angeles, CA, USA
| | - Carla M Koehler
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - Joanna C Jen
- Department of Neurology, University of California, Los Angeles, CA, USA.,Department of Neurobiology, University of California, Los Angeles, CA, USA
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27
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Braunisch MC, Gallwitz H, Abicht A, Diebold I, Holinski-Feder E, Van Maldergem L, Lammens M, Kovács-Nagy R, Alhaddad B, Strom TM, Meitinger T, Senderek J, Rudnik-Schöneborn S, Haack TB. Extension of the phenotype of biallelic loss-of-function mutations in SLC25A46 to the severe form of pontocerebellar hypoplasia type I. Clin Genet 2017; 93:255-265. [PMID: 28653766 DOI: 10.1111/cge.13084] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Revised: 06/18/2017] [Accepted: 06/20/2017] [Indexed: 01/04/2023]
Abstract
Biallelic mutations in SLC25A46, encoding a modified solute transporter involved in mitochondrial dynamics, have been identified in a wide range of conditions such as hereditary motor and sensory neuropathy with optic atrophy type VIB (OMIM: *610826) and congenital lethal pontocerebellar hypoplasia (PCH). To date, 18 patients from 13 families have been reported, presenting with the key clinical features of optic atrophy, peripheral neuropathy, and cerebellar atrophy. The course of the disease was highly variable ranging from severe muscular hypotonia at birth and early death to first manifestations in late childhood and survival into the fifties. Here we report on 4 patients from 2 families diagnosed with PCH who died within the first month of life from respiratory insufficiency. Patients from 1 family had pathoanatomically proven spinal motor neuron degeneration (PCH1). Using exome sequencing, we identified biallelic disease-segregating loss-of-function mutations in SLC25A46 in both families. Our study adds to the definition of the SLC25A46-associated phenotypic spectrum that includes neonatal fatalities due to PCH as the severe extreme.
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Affiliation(s)
- M C Braunisch
- Institute of Human Genetics, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.,Department of Nephrology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - H Gallwitz
- Department of Pediatrics, Socio-Pediatric Center, Klinikum Memmingen, Memmingen, Germany
| | - A Abicht
- Medical Genetics Center, Munich, Germany.,Friedrich-Baur-Institut, Neurologische Klinik und Poliklinik, Klinikum der Universität München, Munich, Germany
| | - I Diebold
- Medical Genetics Center, Munich, Germany
| | - E Holinski-Feder
- Medical Genetics Center, Munich, Germany.,Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Munich, Germany
| | - L Van Maldergem
- Center for Human Genetics, University of Franche-Comté, Besançon, France
| | - M Lammens
- Department of Pathology, Antwerp University Hospital, Edegem, Belgium.,Department of Neuropathology, Born Bunge Institute, Antwerp University, Wilrijk, Belgium
| | - R Kovács-Nagy
- Institute of Human Genetics, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - B Alhaddad
- Institute of Human Genetics, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - T M Strom
- Institute of Human Genetics, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.,Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - T Meitinger
- Institute of Human Genetics, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.,Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - J Senderek
- Friedrich-Baur-Institut, Neurologische Klinik und Poliklinik, Klinikum der Universität München, Munich, Germany
| | - S Rudnik-Schöneborn
- Division of Human Genetics, Medical University Innsbruck, Innsbruck, Austria.,Institut für Humangenetik, Uniklinik RWTH Aachen, Aachen, Germany
| | - T B Haack
- Institute of Human Genetics, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.,Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany.,Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
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28
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Mitochondrial contact site and cristae organizing system: A central player in membrane shaping and crosstalk. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:1481-1489. [PMID: 28526561 DOI: 10.1016/j.bbamcr.2017.05.004] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 05/01/2017] [Indexed: 01/08/2023]
Abstract
Mitochondria are multifunctional metabolic factories and integrative signaling organelles of eukaryotic cells. The structural basis for their numerous functions is a complex and dynamic double-membrane architecture. The outer membrane connects mitochondria to the cytosol and other organelles. The inner membrane is composed of a boundary region and highly folded cristae membranes. The evolutionarily conserved mitochondrial contact site and cristae organizing system (MICOS) connects the two inner membrane domains via formation and stabilization of crista junction structures. Moreover, MICOS establishes contact sites between inner and outer mitochondrial membranes by interacting with outer membrane protein complexes. MICOS deficiency leads to a grossly altered inner membrane architecture resulting in far-reaching functional perturbations in mitochondria. Consequently, mutations affecting the function of MICOS are responsible for a diverse spectrum of human diseases. In this article, we summarize recent insights and concepts on the role of MICOS in the organization of mitochondrial membranes. This article is part of a Special Issue entitled: Membrane Contact Sites edited by Christian Ungermann and Benoit Kornmann.
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29
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Bovine and murine models highlight novel roles for SLC25A46 in mitochondrial dynamics and metabolism, with implications for human and animal health. PLoS Genet 2017; 13:e1006597. [PMID: 28376083 PMCID: PMC5380314 DOI: 10.1371/journal.pgen.1006597] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 01/21/2017] [Indexed: 12/11/2022] Open
Abstract
Neuropathies are neurodegenerative diseases affecting humans and other mammals. Many genetic causes have been identified so far, including mutations of genes encoding proteins involved in mitochondrial dynamics. Recently, the “Turning calves syndrome”, a novel sensorimotor polyneuropathy was described in the French Rouge-des-Prés cattle breed. In the present study, we determined that this hereditary disease resulted from a single nucleotide substitution in SLC25A46, a gene encoding a protein of the mitochondrial carrier family. This mutation caused an apparent damaging amino-acid substitution. To better understand the function of this protein, we knocked out the Slc25a46 gene in a mouse model. This alteration affected not only the nervous system but also altered general metabolism, resulting in premature mortality. Based on optic microscopy examination, electron microscopy and on biochemical, metabolic and proteomic analyses, we showed that the Slc25a46 disruption caused a fusion/fission imbalance and an abnormal mitochondrial architecture that disturbed mitochondrial metabolism. These data extended the range of phenotypes associated with Slc25a46 dysfunction. Moreover, this Slc25a46 knock-out mouse model should be useful to further elucidate the role of SLC25A46 in mitochondrial dynamics. Mitochondria are essential organelles, the site of numerous biochemical reactions, with a critical role in delivering energy to cells, particularly in the nervous system. Consequently, disrupted mitochondrial function often results in neurodegenerative diseases, in humans and in other mammals. Herein, we determined that the “Turning calves syndrome”, a new hereditary sensorimotor polyneuropathy in the French Rouge-des-Prés cattle breed was due to a single substitution in SLC25A46, a gene encoding a protein of the mitochondrial carrier family. We created a mouse knock-out model and determined that disruption of this gene dramatically disturbed mitochondrial dynamics in various organs that resulted in altered metabolism and early death, indirectly confirming the gene identification in cattle. Moreover, our novel findings extended the range of phenotypes associated with polymorphisms of this gene and help to elucidate the role of SLC25A46 in mitochondrial function.
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30
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Novel insights into SLC25A46-related pathologies in a genetic mouse model. PLoS Genet 2017; 13:e1006656. [PMID: 28376086 PMCID: PMC5380310 DOI: 10.1371/journal.pgen.1006656] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 02/26/2017] [Indexed: 11/19/2022] Open
Abstract
The mitochondrial protein SLC25A46 has been recently identified as a novel pathogenic cause in a wide spectrum of neurological diseases, including inherited optic atrophy, Charcot-Marie-Tooth type 2, Leigh syndrome, progressive myoclonic ataxia and lethal congenital pontocerebellar hypoplasia. SLC25A46 is an outer membrane protein, member of the Solute Carrier 25 (SLC25) family of nuclear genes encoding mitochondrial carriers, with a role in mitochondrial dynamics and cristae maintenance. Here we identified a loss-of-function mutation in the Slc25a46 gene that causes lethal neuropathology in mice. Mutant mice manifest the main clinical features identified in patients, including ataxia, optic atrophy and cerebellar hypoplasia, which were completely rescued by expression of the human ortholog. Histopathological analysis revealed previously unseen lesions, most notably disrupted cytoarchitecture in the cerebellum and retina and prominent abnormalities in the neuromuscular junction. A distinct lymphoid phenotype was also evident. Our mutant mice provide a valid model for understanding the mechanistic basis of the complex SLC25A46-mediated pathologies, as well as for screening potential therapeutic interventions. Neurodegenerative diseases encompass a wide range of clinical conditions remaining incurable while the genetic and molecular basis of most of these conditions remains unknown due to their heterogeneity and the lack of animal models. Mutations in nuclear genes encoding mitochondrial proteins have recently emerged as novel causalities in diseases affecting the nervous system. SLC25A46, a novel mitochondrial protein, has recently been identified as a pathogenic target in a wide spectrum of rare genetic neurological diseases, including optic atrophy, Charcot-Marie-Tooth type 2, Leigh syndrome, progressive myoclonic ataxia and lethal congenital pontocerebellar hypoplasia. Following a genetic approach, we identified a novel neurological mouse model caused by a functional mutation in the Slc25a46 gene. Our SLC25A46 mutant mice constitute the first genetic animal model for this disease and represent an ideal tool for elucidating the underlying molecular mechanisms. The aim of this study was to characterize the complex phenotype displayed by the mutant mice in order to understand the mechanistic basis of the SLC25A46-mediated pathologies.
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31
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Sulaiman RA, Patel N, Alsharif H, Arold ST, Alkuraya FS. A novel mutation in SLC25A46 causes optic atrophy and progressive limb spasticity, with no cerebellar atrophy or axonal neuropathy. Clin Genet 2017; 92:230-231. [PMID: 28369803 DOI: 10.1111/cge.12963] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 01/02/2017] [Accepted: 01/03/2017] [Indexed: 02/01/2023]
Affiliation(s)
- R A Sulaiman
- Department of Medical Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - N Patel
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - H Alsharif
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - S T Arold
- Division of Biological and Environmental Sciences and Engineering, Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - F S Alkuraya
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
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32
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Janer A, Prudent J, Paupe V, Fahiminiya S, Majewski J, Sgarioto N, Des Rosiers C, Forest A, Lin ZY, Gingras AC, Mitchell G, McBride HM, Shoubridge EA. SLC25A46 is required for mitochondrial lipid homeostasis and cristae maintenance and is responsible for Leigh syndrome. EMBO Mol Med 2016; 8:1019-38. [PMID: 27390132 PMCID: PMC5009808 DOI: 10.15252/emmm.201506159] [Citation(s) in RCA: 127] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Mitochondria form a dynamic network that responds to physiological signals and metabolic stresses by altering the balance between fusion and fission. Mitochondrial fusion is orchestrated by conserved GTPases MFN1/2 and OPA1, a process coordinated in yeast by Ugo1, a mitochondrial metabolite carrier family protein. We uncovered a homozygous missense mutation in SLC25A46, the mammalian orthologue of Ugo1, in a subject with Leigh syndrome. SLC25A46 is an integral outer membrane protein that interacts with MFN2, OPA1, and the mitochondrial contact site and cristae organizing system (MICOS) complex. The subject mutation destabilizes the protein, leading to mitochondrial hyperfusion, alterations in endoplasmic reticulum (ER) morphology, impaired cellular respiration, and premature cellular senescence. The MICOS complex is disrupted in subject fibroblasts, resulting in strikingly abnormal mitochondrial architecture, with markedly shortened cristae. SLC25A46 also interacts with the ER membrane protein complex EMC, and phospholipid composition is altered in subject mitochondria. These results show that SLC25A46 plays a role in a mitochondrial/ER pathway that facilitates lipid transfer, and link altered mitochondrial dynamics to early‐onset neurodegenerative disease and cell fate decisions.
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Affiliation(s)
- Alexandre Janer
- Department of Human Genetics, McGill University, Montreal, QC, Canada Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Julien Prudent
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
| | - Vincent Paupe
- Department of Human Genetics, McGill University, Montreal, QC, Canada Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | | | - Jacek Majewski
- Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Nicolas Sgarioto
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Christine Des Rosiers
- Department of Nutrition, Université de Montréal, Montreal, QC, Canada Research Centre, Montreal Heart Institute, Montreal, QC, Canada
| | - Anik Forest
- Department of Nutrition, Université de Montréal, Montreal, QC, Canada Research Centre, Montreal Heart Institute, Montreal, QC, Canada
| | - Zhen-Yuan Lin
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Grant Mitchell
- Division of Medical Genetics, Department of Pediatrics, CHU Sainte-Justine and Université de Montréal, Montreal, QC, Canada
| | - Heidi M McBride
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
| | - Eric A Shoubridge
- Department of Human Genetics, McGill University, Montreal, QC, Canada Montreal Neurological Institute, McGill University, Montreal, QC, Canada
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