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Zhu M, Zeiss C, Hamrick MW, Weinstein RS, Sun BH, Brotto M, Liu X, Siu E, Huttner A, Tommasini S, Simpson C, Insogna K. Mitofusin 2 plays a critical role in maintaining the functional integrity of the neuromuscular-skeletal axis. Bone 2024; 184:117086. [PMID: 38552893 DOI: 10.1016/j.bone.2024.117086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 03/22/2024] [Accepted: 03/23/2024] [Indexed: 05/12/2024]
Abstract
PURPOSE Mitofusin 2 (Mfn2) is one of two mitofusins involved in regulating mitochondrial size, shape and function, including mitophagy, an important cellular mechanism to limit oxidative stress. Reduced expression of Mfn2 has been associated with impaired osteoblast differentiation and function and a reduction in the number of viable osteocytes in bone. We hypothesized that the genetic absence of Mfn2 in these cells would increase their susceptibility to aging-associated metabolic stress, leading to a progressive impairment in skeletal homeostasis over time. METHODS Mfn2 was selectively deleted in vivo at three different stages of osteoblast lineage commitment by crossing mice in which the Mfn2 gene was floxed with transgenic mice expressing Cre under the control of the promoter for Osterix (OSX), collagen1a1, or DMP1 (Dentin Matrix Acidic Phosphoprotein 1). RESULTS Mice in which Mfn2 was deleted using DMP1-cre demonstrated a progressive and dramatic decline in bone mineral density (BMD) beginning at 10 weeks of age (n = 5 for each sex and each genotype from age 10 to 20 weeks). By 15 weeks, there was evidence for a functional decline in muscle performance as assessed using a rotarod apparatus (n = 3; 2 males/ 1 female for each genotype), accompanied by a decline in lean body mass. A marked reduction in trabecular bone mass was evident on bone histomorphometry, and biomechanical testing at 25 weeks (k/o: 2 male/1 female, control 2 male/2 female) revealed severely impaired femur strength. Extensive regional myofiber atrophy and degeneration was observed on skeletal muscle histology. Electron microscopy showed progressive disruption of cellular architecture, with disorganized sarcomeres and a bloated mitochondrial reticulum. There was also evidence of neurodegeneration within the ventral horn and roots of the lumbar spinal cord, which was accompanied by myelin loss and myofiber atrophy. Deletion of Mfn2 using OSX-cre or Col1a1-cre did not result in a musculoskeletal phenotype. Where possible, male and female animals were analyzed separately, but small numbers of animals in each group limited statistical power. For other outcomes, where sex was not considered, small sample sizes might still limit the strength of the observation. CONCLUSION Despite known functional overlap of Mfn1 and Mfn2 in some tissues, and their co-expression in bone, muscle and spinal cord, deletion of Mfn2 using the 8 kB DMP1 promoter uncovered an important non-redundant role for Mfn2 in maintaining the neuromuscular/bone axis.
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Affiliation(s)
- Meiling Zhu
- Yale School of Medicine, Section of Endocrinology, New Haven, CT, USA
| | - Caroline Zeiss
- Yale School of Medicine, Section of Comparative Medicine, New Haven, CT, USA
| | - Mark W Hamrick
- Department of Orthopaedic Surgery, Institute of Molecular Medicine & Genetics, Medical College of Georgia, Augusta, GA, USA
| | - Robert S Weinstein
- Division of Endocrinology, Metabolic Bone Diseases, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Ben-Hua Sun
- Yale School of Medicine, Section of Endocrinology, New Haven, CT, USA
| | - Marco Brotto
- Bone-Muscle Research Center, College of Nursing & Health Innovation, University of Texas at Arlington, Arlington, TX, USA
| | - Xinran Liu
- Yale School of Medicine, Center for Cellular and Molecular Imaging, New Haven, CT, USA
| | - Edwin Siu
- Yale School of Medicine, Section of Endocrinology, New Haven, CT, USA
| | - Anita Huttner
- Yale School of Medicine, Department of Pathology, New Haven, CT, USA
| | - Steven Tommasini
- Yale School of Medicine, Department of Orthopaedics & Rehabilitation, New Haven, CT, USA
| | - Christine Simpson
- Yale School of Medicine, Section of Endocrinology, New Haven, CT, USA
| | - Karl Insogna
- Yale School of Medicine, Section of Endocrinology, New Haven, CT, USA.
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Abati E, Rizzuti M, Anastasia A, Comi GP, Corti S, Rizzo F. Charcot-Marie-Tooth type 2A in vivo models: Current updates. J Cell Mol Med 2024; 28:e18293. [PMID: 38722298 PMCID: PMC11081012 DOI: 10.1111/jcmm.18293] [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: 01/16/2024] [Revised: 03/13/2024] [Accepted: 03/25/2024] [Indexed: 05/12/2024] Open
Abstract
Charcot-Marie-Tooth type 2A (CMT2A) is an inherited sensorimotor neuropathy associated with mutations within the Mitofusin 2 (MFN2) gene. These mutations impair normal mitochondrial functioning via different mechanisms, disturbing the equilibrium between mitochondrial fusion and fission, of mitophagy and mitochondrial axonal transport. Although CMT2A disease causes a significant disability, no resolutive treatment for CMT2A patients to date. In this context, reliable experimental models are essential to precisely dissect the molecular mechanisms of disease and to devise effective therapeutic strategies. The most commonly used models are either in vitro or in vivo, and among the latter murine models are by far the most versatile and popular. Here, we critically revised the most relevant literature focused on the experimental models, providing an update on the mammalian models of CMT2A developed to date. We highlighted the different phenotypic, histopathological and molecular characteristics, and their use in translational studies for bringing potential therapies from the bench to the bedside. In addition, we discussed limitations of these models and perspectives for future improvement.
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Affiliation(s)
- Elena Abati
- Neurology Unit, Foundation IRCCS Ca' Granda Ospedale Maggiore PoliclinicoMilanItaly
- Department of Pathophysiology and Transplantation, Dino Ferrari CenterUniversità degli Studi di MilanoMilanItaly
| | - Mafalda Rizzuti
- Neurology Unit, Foundation IRCCS Ca' Granda Ospedale Maggiore PoliclinicoMilanItaly
| | - Alessia Anastasia
- Neurology Unit, Foundation IRCCS Ca' Granda Ospedale Maggiore PoliclinicoMilanItaly
| | - Giacomo Pietro Comi
- Neurology Unit, Foundation IRCCS Ca' Granda Ospedale Maggiore PoliclinicoMilanItaly
- Department of Pathophysiology and Transplantation, Dino Ferrari CenterUniversità degli Studi di MilanoMilanItaly
| | - Stefania Corti
- Department of Pathophysiology and Transplantation, Dino Ferrari CenterUniversità degli Studi di MilanoMilanItaly
- Neuromuscular and Rare Diseases Unit, Department of NeuroscienceFondazione IRCCS Ca' Granda Ospedale Maggiore PoliclinicoMilanItaly
| | - Federica Rizzo
- Neurology Unit, Foundation IRCCS Ca' Granda Ospedale Maggiore PoliclinicoMilanItaly
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Alberti C, Rizzo F, Anastasia A, Comi G, Corti S, Abati E. Charcot-Marie-tooth disease type 2A: An update on pathogenesis and therapeutic perspectives. Neurobiol Dis 2024; 193:106467. [PMID: 38452947 DOI: 10.1016/j.nbd.2024.106467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 03/04/2024] [Accepted: 03/04/2024] [Indexed: 03/09/2024] Open
Abstract
Mutations in the gene encoding MFN2 have been identified as associated with Charcot-Marie-Tooth disease type 2A (CMT2A), a neurological disorder characterized by a broad clinical phenotype involving the entire nervous system. MFN2, a dynamin-like GTPase protein located on the outer mitochondrial membrane, is well-known for its involvement in mitochondrial fusion. Numerous studies have demonstrated its participation in a network crucial for various other mitochondrial functions, including mitophagy, axonal transport, and its controversial role in endoplasmic reticulum (ER)-mitochondria contacts. Considerable progress has been made in the last three decades in elucidating the disease pathogenesis, aided by the generation of animal and cellular models that have been instrumental in studying disease physiology. A review of the literature reveals that, up to now, no definitive pharmacological treatment for any CMT2A variant has been established; nonetheless, recent years have witnessed substantial progress. Many treatment approaches, especially concerning molecular therapy, such as histone deacetylase inhibitors, peptide therapy to increase mitochondrial fusion, the new therapeutic strategies based on MF1/MF2 balance, and SARM1 inhibitors, are currently in preclinical testing. The literature on gene silencing and gene replacement therapies is still limited, except for a recent study by Rizzo et al.(Rizzo et al., 2023), which recently first achieved encouraging results in in vitro and in vivo models of the disease. The near-future goal for these promising therapies is to progress to the stage of clinical translation.
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Affiliation(s)
- Claudia Alberti
- Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy
| | - Federica Rizzo
- Neurology Unit, Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Alessia Anastasia
- Neurology Unit, Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Giacomo Comi
- Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy; Neurology Unit, Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Stefania Corti
- Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy; Neuromuscular and Rare Diseases Unit, Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Elena Abati
- Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy; Neurology Unit, Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
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Hayashi H, Saito R, Tanaka H, Hara N, Koide S, Yonemochi Y, Ozawa T, Hokari M, Toyoshima Y, Miyashita A, Onodera O, Okamoto K, Ikeuchi T, Nakajima T, Kakita A. Clinicopathologic features of two unrelated autopsied patients with Charcot-Marie-Tooth disease carrying MFN2 gene mutation. Acta Neuropathol Commun 2023; 11:207. [PMID: 38124143 PMCID: PMC10734194 DOI: 10.1186/s40478-023-01692-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 11/12/2023] [Indexed: 12/23/2023] Open
Affiliation(s)
- Hideki Hayashi
- Department of Pathology, Brain Research Institute, Niigata University, 1-757 Asahimachi, Chuo-Ku, Niigata, 951-8585, Japan
- Department of Neurology, Brain Research Institute, Niigata University, 1-757 Asahimachi, Chuo-Ku, Niigata, 951-8585, Japan
| | - Rie Saito
- Department of Pathology, Brain Research Institute, Niigata University, 1-757 Asahimachi, Chuo-Ku, Niigata, 951-8585, Japan.
| | - Hidetomo Tanaka
- Department of Pathology, Brain Research Institute, Niigata University, 1-757 Asahimachi, Chuo-Ku, Niigata, 951-8585, Japan
| | - Norikazu Hara
- Department of Molecular Genetics, Brain Research Institute, Niigata University, 1-757 Asahimachi, Chuo-Ku, Niigata, 951-8585, Japan
| | - Shin Koide
- Department of Neurology, Brain Research Institute, Niigata University, 1-757 Asahimachi, Chuo-Ku, Niigata, 951-8585, Japan
- Departments of Neurology, National Hospital Organization Niigata National Hospital, 3-52 Akasakachou, Kashiwazaki, 945-8585, Japan
| | - Yosuke Yonemochi
- Departments of Neurology, National Hospital Organization Niigata National Hospital, 3-52 Akasakachou, Kashiwazaki, 945-8585, Japan
| | - Tetsuo Ozawa
- Department of Internal Medicine, National Hospital Organization Niigata National Hospital, 3-52 Akasakachou, Kashiwazaki, 945-8585, Japan
| | - Mariko Hokari
- Department of Pathology, Brain Research Institute, Niigata University, 1-757 Asahimachi, Chuo-Ku, Niigata, 951-8585, Japan
- Department of Neurology, Brain Research Institute, Niigata University, 1-757 Asahimachi, Chuo-Ku, Niigata, 951-8585, Japan
- Department of Neurology, Niigata City General Hospital, 463-7 Shumoku, Chuo-Ku, Niigata, 950-1197, Japan
| | - Yasuko Toyoshima
- Department of Pathology, Brain Research Institute, Niigata University, 1-757 Asahimachi, Chuo-Ku, Niigata, 951-8585, Japan
- Department of Neurology, Brain Disease Center, Agano Hospital, 6317-15 Yasuda, Agano, Niigata, 959-2221, Japan
| | - Akinori Miyashita
- Department of Molecular Genetics, Brain Research Institute, Niigata University, 1-757 Asahimachi, Chuo-Ku, Niigata, 951-8585, Japan
| | - Osamu Onodera
- Department of Neurology, Brain Research Institute, Niigata University, 1-757 Asahimachi, Chuo-Ku, Niigata, 951-8585, Japan
| | - Kouichirou Okamoto
- Department of Translational Research, Brain Research Institute, Niigata University, 1-757 Asahimachi, Chuo-Ku, Niigata, 951-8585, Japan
| | - Takeshi Ikeuchi
- Department of Molecular Genetics, Brain Research Institute, Niigata University, 1-757 Asahimachi, Chuo-Ku, Niigata, 951-8585, Japan
| | - Takashi Nakajima
- Departments of Neurology, National Hospital Organization Niigata National Hospital, 3-52 Akasakachou, Kashiwazaki, 945-8585, Japan
| | - Akiyoshi Kakita
- Department of Pathology, Brain Research Institute, Niigata University, 1-757 Asahimachi, Chuo-Ku, Niigata, 951-8585, Japan
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Kontogeorgiou Z, Kartanou C, Rentzos M, Kokotis P, Anagnostou E, Zambelis T, Chroni E, Dinopoulos A, Panas M, Koutsis G, Karadima G. Mutational screening of Greek patients with axonal Charcot-Marie-Tooth disease using targeted next-generation sequencing: Clinical and molecular spectrum delineation. J Peripher Nerv Syst 2023; 28:642-650. [PMID: 37747677 DOI: 10.1111/jns.12598] [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: 08/02/2023] [Revised: 09/04/2023] [Accepted: 09/22/2023] [Indexed: 09/26/2023]
Abstract
BACKGROUND AND AIMS Axonal forms of Charcot-Marie-Tooth disease (CMT) are classified as CMT2, distal hereditary motor neuropathy (dHMN) or hereditary sensory neuropathy (HSN) and can be caused by mutations in over 100 genes. We presently aimed to investigate for the first time the genetic landscape of axonal CMT in the Greek population. METHODS Sixty index patients with CMT2, dHMN or HSN were screened by a combination of Sanger sequencing (GJB1) and next-generation sequencing custom-made gene panel covering 24 commonly mutated genes in axonal CMT. RESULTS Overall, 20 variants classified as pathogenic or likely pathogenic were identified in heterozygous state in 20 index cases, representing 33.3% of the cohort. Of these, 14 were known pathogenic/likely pathogenic and six were designated as such according to ACMG classification, after in silico evaluation, testing for familial segregation and further literature review. The most frequently involved genes were GJB1 (11.7%), MPZ (5%) and MFN2 (5%), followed by DNM2 (3.3%) and LRSAM1 (3.3%). Single cases were identified with mutations in BSCL2, HSPB1 and GDAP1. INTERPRETATION A wide phenotypic variability in terms of severity and age of onset was noted. Given the limited number of genes tested, the diagnostic yield of the present panel compares favourably with studies in other European populations. Our study delineates the genetic and phenotypic variability of inherited axonal neuropathies in the Greek population and contributes to the pathogenicity characterization of further variants linked to axonal neuropathies.
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Affiliation(s)
- Zoi Kontogeorgiou
- Neurogenetics Unit, 1st Department of Neurology, Eginition Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Chrisoula Kartanou
- Neurogenetics Unit, 1st Department of Neurology, Eginition Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Michail Rentzos
- 1st Department of Neurology, Eginition Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Panagiotis Kokotis
- Clinical Neurophysiology Unit, 1st Department of Neurology, Eginition Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Evangelos Anagnostou
- Clinical Neurophysiology Unit, 1st Department of Neurology, Eginition Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Thomas Zambelis
- Clinical Neurophysiology Unit, 1st Department of Neurology, Eginition Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Elisabeth Chroni
- Department of Neurology, School of Medicine, University of Patras, Patras, Greece
| | - Argyris Dinopoulos
- 3rd Department of Pediatrics, General Hospital of Athens Attikon, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Marios Panas
- Neurogenetics Unit, 1st Department of Neurology, Eginition Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Georgios Koutsis
- Neurogenetics Unit, 1st Department of Neurology, Eginition Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Georgia Karadima
- Neurogenetics Unit, 1st Department of Neurology, Eginition Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
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Rizzo F, Bono S, Ruepp MD, Salani S, Ottoboni L, Abati E, Melzi V, Cordiglieri C, Pagliarani S, De Gioia R, Anastasia A, Taiana M, Garbellini M, Lodato S, Kunderfranco P, Cazzato D, Cartelli D, Lonati C, Bresolin N, Comi G, Nizzardo M, Corti S. Combined RNA interference and gene replacement therapy targeting MFN2 as proof of principle for the treatment of Charcot-Marie-Tooth type 2A. Cell Mol Life Sci 2023; 80:373. [PMID: 38007410 PMCID: PMC10676309 DOI: 10.1007/s00018-023-05018-w] [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: 04/14/2023] [Revised: 10/23/2023] [Accepted: 10/26/2023] [Indexed: 11/27/2023]
Abstract
Mitofusin-2 (MFN2) is an outer mitochondrial membrane protein essential for mitochondrial networking in most cells. Autosomal dominant mutations in the MFN2 gene cause Charcot-Marie-Tooth type 2A disease (CMT2A), a severe and disabling sensory-motor neuropathy that impacts the entire nervous system. Here, we propose a novel therapeutic strategy tailored to correcting the root genetic defect of CMT2A. Though mutant and wild-type MFN2 mRNA are inhibited by RNA interference (RNAi), the wild-type protein is restored by overexpressing cDNA encoding functional MFN2 modified to be resistant to RNAi. We tested this strategy in CMT2A patient-specific human induced pluripotent stem cell (iPSC)-differentiated motor neurons (MNs), demonstrating the correct silencing of endogenous MFN2 and replacement with an exogenous copy of the functional wild-type gene. This approach significantly rescues the CMT2A MN phenotype in vitro, stabilizing the altered axonal mitochondrial distribution and correcting abnormal mitophagic processes. The MFN2 molecular correction was also properly confirmed in vivo in the MitoCharc1 CMT2A transgenic mouse model after cerebrospinal fluid (CSF) delivery of the constructs into newborn mice using adeno-associated virus 9 (AAV9). Altogether, our data support the feasibility of a combined RNAi and gene therapy strategy for treating the broad spectrum of human diseases associated with MFN2 mutations.
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Affiliation(s)
- Federica Rizzo
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Silvia Bono
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Marc David Ruepp
- United Kingdom Dementia Research Institute Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, UK
| | - Sabrina Salani
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Linda Ottoboni
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Elena Abati
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Valentina Melzi
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Chiara Cordiglieri
- Istituto Di Genetica Molecolare "Romeo Ed Enrica Invernizzi", Milan, Italy
| | - Serena Pagliarani
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Roberta De Gioia
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Alessia Anastasia
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Michela Taiana
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | | | - Simona Lodato
- Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, 20072, Milan, Italy
- IRCCS Humanitas Research Hospital, Rozzano, 20089, Milan, Italy
| | - Paolo Kunderfranco
- Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, 20072, Milan, Italy
- IRCCS Humanitas Research Hospital, Rozzano, 20089, Milan, Italy
| | - Daniele Cazzato
- Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | | | - Caterina Lonati
- Center for Preclinical Research, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Pace 9, 20100, Milan, Italy
| | - Nereo Bresolin
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy
| | - Giacomo Comi
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy
| | - Monica Nizzardo
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Stefania Corti
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy.
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Neuromuscular and Rare Diseases Unit, Milan, Italy.
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7
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Zhang Y, Pang D, Wang Z, Ma L, Chen Y, Yang L, Xiao W, Yuan H, Chang F, Ouyang H. An integrative analysis of genotype-phenotype correlation in Charcot Marie Tooth type 2A disease with MFN2 variants: A case and systematic review. Gene 2023; 883:147684. [PMID: 37536398 DOI: 10.1016/j.gene.2023.147684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/24/2023] [Accepted: 07/31/2023] [Indexed: 08/05/2023]
Abstract
Dominant genetic variants in the mitofusin 2 (MFN2) gene lead to Charcot-Marie-Tooth type 2A (CMT2A), a neurodegenerative disease caused by genetic defects that directly damage axons. In this study, we reported a proband with a pathogenic variant in the GTPase domain of MFN2, c.494A > G (p.His165Arg). To date, at least 184 distinct MFN2 variants identified in 944 independent probands have been reported in 131 references. However, the field of medical genetics has long been challenged by how genetic variation in the MFN2 gene is associated with disease phenotypes. Here, by collating the MFN2 variant data and patient clinical information from Leiden Open Variant Database 3.0, NCBI clinvar database, and available related references in PubMed, we determined the mutation frequency, age of onset, sex ratio, and geographical distribution. Furthermore, the results of an analysis examining the relationship between variants and phenotypes from multiple genetic perspectives indicated that insertion and deletions (indels), copy number variants (CNVs), duplication variants, and nonsense mutations in single nucleotide variants (SNVs) tend to be pathogenic, and the results emphasized the importance of the GTPase domain to the structure and function of MFN2. Overall, three reliable classification methods of MFN2 genotype-phenotype associations provide insights into the prediction of CMT2A disease severity. Of course, there are still many MFN2 variants that have not been given clear clinical significance, which requires clinicians to make more accurate clinical diagnoses.
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Affiliation(s)
- Yuanzhu Zhang
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China.
| | - Daxin Pang
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China; Chongqing Research Institute, Jilin University, Chongqing 401120, China; Chongqing Jitang Biotechnology Research Institute Co., Ltd., Chongqing 401120, China.
| | - Ziru Wang
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China.
| | - Lerong Ma
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China.
| | - Yiwu Chen
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China.
| | - Lin Yang
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China.
| | - Wenyu Xiao
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China.
| | - Hongming Yuan
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China; Chongqing Research Institute, Jilin University, Chongqing 401120, China.
| | - Fei Chang
- Department of Orthopedics, The Second Hospital of Jilin University, Changchun 130022, China.
| | - Hongsheng Ouyang
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China; Chongqing Research Institute, Jilin University, Chongqing 401120, China; Chongqing Jitang Biotechnology Research Institute Co., Ltd., Chongqing 401120, China.
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8
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Tribble JR, Hui F, Quintero H, El Hajji S, Bell K, Di Polo A, Williams PA. Neuroprotection in glaucoma: Mechanisms beyond intraocular pressure lowering. Mol Aspects Med 2023; 92:101193. [PMID: 37331129 DOI: 10.1016/j.mam.2023.101193] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/25/2023] [Accepted: 06/04/2023] [Indexed: 06/20/2023]
Abstract
Glaucoma is a common, complex, multifactorial neurodegenerative disease characterized by progressive dysfunction and then loss of retinal ganglion cells, the output neurons of the retina. Glaucoma is the most common cause of irreversible blindness and affects ∼80 million people worldwide with many more undiagnosed. The major risk factors for glaucoma are genetics, age, and elevated intraocular pressure. Current strategies only target intraocular pressure management and do not directly target the neurodegenerative processes occurring at the level of the retinal ganglion cell. Despite strategies to manage intraocular pressure, as many as 40% of glaucoma patients progress to blindness in at least one eye during their lifetime. As such, neuroprotective strategies that target the retinal ganglion cell and these neurodegenerative processes directly are of great therapeutic need. This review will cover the recent advances from basic biology to on-going clinical trials for neuroprotection in glaucoma covering degenerative mechanisms, metabolism, insulin signaling, mTOR, axon transport, apoptosis, autophagy, and neuroinflammation. With an increased understanding of both the basic and clinical mechanisms of the disease, we are closer than ever to a neuroprotective strategy for glaucoma.
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Affiliation(s)
- James R Tribble
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Flora Hui
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia; Department of Optometry & Vision Sciences, The University of Melbourne, Melbourne, Australia
| | - Heberto Quintero
- Department of Neuroscience, University of Montreal, Montreal, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Canada
| | - Sana El Hajji
- Department of Neuroscience, University of Montreal, Montreal, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Canada
| | - Katharina Bell
- NHMRC Clinical Trials Centre, University of Sydney, Australia; Eye ACP Duke-NUS, Singapore
| | - Adriana Di Polo
- Department of Neuroscience, University of Montreal, Montreal, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Canada
| | - Pete A Williams
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
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9
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Glytsou C, Chen X, Zacharioudakis E, Al-Santli W, Zhou H, Nadorp B, Lee S, Lasry A, Sun Z, Papaioannou D, Cammer M, Wang K, Zal T, Zal MA, Carter BZ, Ishizawa J, Tibes R, Tsirigos A, Andreeff M, Gavathiotis E, Aifantis I. Mitophagy Promotes Resistance to BH3 Mimetics in Acute Myeloid Leukemia. Cancer Discov 2023; 13:1656-1677. [PMID: 37088914 PMCID: PMC10330144 DOI: 10.1158/2159-8290.cd-22-0601] [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: 05/23/2022] [Revised: 01/30/2023] [Accepted: 03/23/2023] [Indexed: 04/25/2023]
Abstract
BH3 mimetics are used as an efficient strategy to induce cell death in several blood malignancies, including acute myeloid leukemia (AML). Venetoclax, a potent BCL-2 antagonist, is used clinically in combination with hypomethylating agents for the treatment of AML. Moreover, MCL1 or dual BCL-2/BCL-xL antagonists are under investigation. Yet, resistance to single or combinatorial BH3-mimetic therapies eventually ensues. Integration of multiple genome-wide CRISPR/Cas9 screens revealed that loss of mitophagy modulators sensitizes AML cells to various BH3 mimetics targeting different BCL-2 family members. One such regulator is MFN2, whose protein levels positively correlate with drug resistance in patients with AML. MFN2 overexpression is sufficient to drive resistance to BH3 mimetics in AML. Insensitivity to BH3 mimetics is accompanied by enhanced mitochondria-endoplasmic reticulum interactions and augmented mitophagy flux, which acts as a prosurvival mechanism to eliminate mitochondrial damage. Genetic or pharmacologic MFN2 targeting synergizes with BH3 mimetics by impairing mitochondrial clearance and enhancing apoptosis in AML. SIGNIFICANCE AML remains one of the most difficult-to-treat blood cancers. BH3 mimetics represent a promising therapeutic approach to eliminate AML blasts by activating the apoptotic pathway. Enhanced mitochondrial clearance drives resistance to BH3 mimetics and predicts poor prognosis. Reverting excessive mitophagy can halt BH3-mimetic resistance in AML. This article is highlighted in the In This Issue feature, p. 1501.
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Affiliation(s)
- Christina Glytsou
- Department of Pathology, NYU Grossman School of Medicine, New York, NY 10016, USA
- Laura & Isaac Perlmutter Cancer Center, NYU Langone Health and NYU Grossman School of Medicine, New York, NY 10016, USA
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers-The State University of New Jersey, Piscataway, NJ 08854, USA
- Department of Pediatrics, Robert Wood Johnson Medical School, and Rutgers Cancer Institute of New Jersey, Rutgers-The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Xufeng Chen
- Department of Pathology, NYU Grossman School of Medicine, New York, NY 10016, USA
- Laura & Isaac Perlmutter Cancer Center, NYU Langone Health and NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Emmanouil Zacharioudakis
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Montefiore Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Wafa Al-Santli
- Department of Pathology, NYU Grossman School of Medicine, New York, NY 10016, USA
- Laura & Isaac Perlmutter Cancer Center, NYU Langone Health and NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Hua Zhou
- Applied Bioinformatics Laboratories, NYU School of Medicine, New York, NY 10016, USA
| | - Bettina Nadorp
- Department of Pathology, NYU Grossman School of Medicine, New York, NY 10016, USA
- Laura & Isaac Perlmutter Cancer Center, NYU Langone Health and NYU Grossman School of Medicine, New York, NY 10016, USA
- Applied Bioinformatics Laboratories, NYU School of Medicine, New York, NY 10016, USA
| | - Soobeom Lee
- Department of Biology, New York University, New York, NY 10003, USA
| | - Audrey Lasry
- Department of Pathology, NYU Grossman School of Medicine, New York, NY 10016, USA
- Laura & Isaac Perlmutter Cancer Center, NYU Langone Health and NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Zhengxi Sun
- Department of Pathology, NYU Grossman School of Medicine, New York, NY 10016, USA
- Laura & Isaac Perlmutter Cancer Center, NYU Langone Health and NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Dimitrios Papaioannou
- Department of Pathology, NYU Grossman School of Medicine, New York, NY 10016, USA
- Laura & Isaac Perlmutter Cancer Center, NYU Langone Health and NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Michael Cammer
- Microscopy Core, Division of Advanced Research Technologies, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Kun Wang
- Department of Pathology, NYU Grossman School of Medicine, New York, NY 10016, USA
- Laura & Isaac Perlmutter Cancer Center, NYU Langone Health and NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Tomasz Zal
- Section of Molecular Hematology and Therapy, Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Malgorzata Anna Zal
- Section of Molecular Hematology and Therapy, Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Bing Z. Carter
- Section of Molecular Hematology and Therapy, Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jo Ishizawa
- Section of Molecular Hematology and Therapy, Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | | | - Aristotelis Tsirigos
- Department of Pathology, NYU Grossman School of Medicine, New York, NY 10016, USA
- Applied Bioinformatics Laboratories, NYU School of Medicine, New York, NY 10016, USA
| | - Michael Andreeff
- Section of Molecular Hematology and Therapy, Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Evripidis Gavathiotis
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Montefiore Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Iannis Aifantis
- Department of Pathology, NYU Grossman School of Medicine, New York, NY 10016, USA
- Laura & Isaac Perlmutter Cancer Center, NYU Langone Health and NYU Grossman School of Medicine, New York, NY 10016, USA
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10
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Hines TJ, Bailey J, Liu H, Guntur AR, Seburn KL, Pratt SL, Funke JR, Tarantino LM, Burgess RW. A Novel ENU-Induced Mfn2 Mutation Causes Motor Deficits in Mice without Causing Peripheral Neuropathy. BIOLOGY 2023; 12:953. [PMID: 37508383 PMCID: PMC10376023 DOI: 10.3390/biology12070953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 06/22/2023] [Accepted: 06/26/2023] [Indexed: 07/30/2023]
Abstract
Mitochondrial fission and fusion are required for maintaining functional mitochondria. The mitofusins (MFN1 and MFN2) are known for their roles in mediating mitochondrial fusion. Recently, MFN2 has been implicated in other important cellular functions, such as mitophagy, mitochondrial motility, and coordinating endoplasmic reticulum-mitochondria communication. In humans, over 100 MFN2 mutations are associated with a form of inherited peripheral neuropathy, Charcot-Marie-Tooth disease type 2A (CMT2A). Here we describe an ENU-induced mutant mouse line with a recessive neuromuscular phenotype. Behavioral screening showed progressive weight loss and rapid deterioration of motor function beginning at 8 weeks. Mapping and sequencing revealed a missense mutation in exon 18 of Mfn2 (T1928C; Leu643Pro), within the transmembrane domain. Compared to wild-type and heterozygous littermates, Mfn2L643P/L643P mice exhibited diminished rotarod performance and decreases in activity in the open field test, muscular endurance, mean mitochondrial diameter, sensory tests, mitochondrial DNA content, and MFN2 protein levels. However, tests of peripheral nerve physiology and histology were largely normal. Mutant leg bones had reduced cortical bone thickness and bone area fraction. Together, our data indicate that Mfn2L643P causes a recessive motor phenotype with mild bone and mitochondrial defects in mice. Lack of apparent nerve pathology notwithstanding, this is the first reported mouse model with a mutation in the transmembrane domain of the protein, which may be valuable for researchers studying MFN2 biology.
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Affiliation(s)
| | - Janice Bailey
- Department of Genetics, The University of North Carolina, Chapel Hill, NC 27599, USA
| | - Hedi Liu
- Department of Genetics, The University of North Carolina, Chapel Hill, NC 27599, USA
| | - Anyonya R Guntur
- Center for Molecular Medicine, Maine Health Institute for Research, Scarborough, ME 04074, USA
| | | | - Samia L Pratt
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
- Neuroscience Program, Graduate School of Biomedical Sciences, Tufts University, Boston, MA 02111, USA
| | - Jonathan R Funke
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
- Neuroscience Program, Graduate School of Biomedical Sciences, Tufts University, Boston, MA 02111, USA
| | - Lisa M Tarantino
- Department of Genetics, The University of North Carolina, Chapel Hill, NC 27599, USA
| | - Robert W Burgess
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
- Neuroscience Program, Graduate School of Biomedical Sciences, Tufts University, Boston, MA 02111, USA
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11
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Okamoto Y, Takashima H. The Current State of Charcot-Marie-Tooth Disease Treatment. Genes (Basel) 2023; 14:1391. [PMID: 37510296 PMCID: PMC10379063 DOI: 10.3390/genes14071391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Revised: 06/20/2023] [Accepted: 06/29/2023] [Indexed: 07/30/2023] Open
Abstract
Charcot-Marie-Tooth disease (CMT) and associated neuropathies are the most predominant genetically transmitted neuromuscular conditions; however, effective pharmacological treatments have not established. The extensive genetic heterogeneity of CMT, which impacts the peripheral nerves and causes lifelong disability, presents a significant barrier to the development of comprehensive treatments. An estimated 100 loci within the human genome are linked to various forms of CMT and its related inherited neuropathies. This review delves into prospective therapeutic strategies used for the most frequently encountered CMT variants, namely CMT1A, CMT1B, CMTX1, and CMT2A. Compounds such as PXT3003, which are being clinically and preclinically investigated, and a broad array of therapeutic agents and their corresponding mechanisms are discussed. Furthermore, the progress in established gene therapy techniques, including gene replacement via viral vectors, exon skipping using antisense oligonucleotides, splicing modification, and gene knockdown, are appraised. Each of these gene therapies has the potential for substantial advancements in future research.
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Affiliation(s)
- Yuji Okamoto
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima 890-8544, Japan
- Department of Physical Therapy, School of Health Sciences, Faculty of Medicine, Kagoshima University, Kagoshima 890-8544, Japan
| | - Hiroshi Takashima
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima 890-8544, Japan
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12
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Dorn GW. Reversing Dysdynamism to Interrupt Mitochondrial Degeneration in Amyotrophic Lateral Sclerosis. Cells 2023; 12:1188. [PMID: 37190097 PMCID: PMC10136928 DOI: 10.3390/cells12081188] [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: 03/01/2023] [Revised: 04/13/2023] [Accepted: 04/14/2023] [Indexed: 05/17/2023] Open
Abstract
Amyotrophic lateral sclerosis is one of several chronic neurodegenerative conditions in which mitochondrial abnormalities are posited to contribute to disease progression. Therapeutic options targeting mitochondria include enhancing metabolism, suppressing reactive oxygen production and disrupting mitochondria-mediated programmed cell death pathways. Herein is reviewed mechanistic evidence supporting a meaningful pathophysiological role for the constellation of abnormal mitochondrial fusion, fission and transport, collectively designated mitochondrial dysdynamism, in ALS. Following this is a discussion on preclinical studies in ALS mice that seemingly validate the idea that normalizing mitochondrial dynamism can delay ALS by interrupting a vicious cycle of mitochondrial degeneration, leading to neuronal die-back and death. Finally, the relative benefits of suppressing mitochondrial fusion vs. enhancing mitochondrial fusion in ALS are speculated upon, and the paper concludes with the prediction that the two approaches could be additive or synergistic, although a side-by-side comparative trial may be challenging to perform.
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Affiliation(s)
- Gerald W Dorn
- Department of Internal Medicine (Pharmacogenomics), Washington University School of Medicine, St. Louis, MO 63110, USA
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13
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Dang X, Zhang L, Franco A, Dorn II GW. Activating mitofusins interrupts mitochondrial degeneration and delays disease progression in SOD1 mutant amyotrophic lateral sclerosis. Hum Mol Genet 2023; 32:1208-1222. [PMID: 36416308 PMCID: PMC10026224 DOI: 10.1093/hmg/ddac287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 10/25/2022] [Accepted: 11/21/2022] [Indexed: 11/24/2022] Open
Abstract
Mitochondrial involvement in neurodegenerative diseases is widespread and multifactorial. Targeting mitochondrial pathology is therefore of interest. The recent development of bioactive molecules that modulate mitochondrial dynamics (fusion, fission and motility) offers a new therapeutic approach for neurodegenerative diseases with either indirect or direct mitochondrial involvement. Here, we asked: (1) Can enhanced mitochondrial fusion and motility improve secondary mitochondrial pathology in superoxide dismutase1 (SOD1) mutant amyotrophic lateral sclerosis (ALS)? And: (2) What is the impact of enhancing mitochondria fitness on in vivo manifestations of SOD1 mutant ALS? We observed that small molecule mitofusin activators corrected mitochondrial fragmentation, depolarization and dysmotility in genetically diverse ALS patient reprogrammed motor neurons and fibroblasts, and in motor neurons, sensory neurons and fibroblasts from SOD1 G93A mice. Continuous, but not intermittent, pharmacologic mitofusin activation delayed phenotype progression and lethality in SOD1 G93A mice, reducing neuron loss and improving neuromuscular connectivity. Mechanistically, mitofusin activation increased mitochondrial motility, fitness and residency within neuromuscular synapses; reduced mitochondrial reactive oxygen species production; and diminished apoptosis in SOD1 mutant neurons. These benefits were accompanied by improved mitochondrial respiratory coupling, despite characteristic SOD1 mutant ALS-associated downregulation of mitochondrial respiratory complexes. Targeting mitochondrial dysdynamism is a promising approach to alleviate pathology caused by secondary mitochondrial dysfunction in some neurodegenerative diseases.
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Affiliation(s)
- Xiawei Dang
- Department of Internal Medicine, Washington University School of Medicine, St. Louis MO USA
- Department of Psychiatry, The First Affiliated Hospital of Xi’an Jiao Tong University, Xi’an, Shaanxi 710061, China
| | - Lihong Zhang
- Department of Internal Medicine, Washington University School of Medicine, St. Louis MO USA
| | - Antonietta Franco
- Department of Internal Medicine, Washington University School of Medicine, St. Louis MO USA
| | - Gerald W Dorn II
- Department of Internal Medicine, Washington University School of Medicine, St. Louis MO USA
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14
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Shahin S, Lu B, Zhou Y, Xu H, Chetsawang J, Baloh RH, Wang S. MFN1 augmentation prevents retinal degeneration in a Charcot-Marie-Tooth type 2A mouse model. iScience 2023; 26:106270. [PMID: 36936780 PMCID: PMC10014277 DOI: 10.1016/j.isci.2023.106270] [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: 10/17/2022] [Revised: 12/30/2022] [Accepted: 02/20/2023] [Indexed: 03/12/2023] Open
Abstract
Charcot-Marie-Tooth disease type 2A (CMT2A), the most common inherited peripheral axonal neuropathy, is associated with more than 100 dominant mutations, including R94Q as the most abundant mutation in the Mitofusin2 (MFN2) gene. CMT2A is characterized by progressive motor and sensory loss, color-vision defects, and progressive loss of visual acuity. We used a well-established transgenic mouse model of CMT2A with R94Q mutation on MFN2 gene (MFN2 R94Q ) to investigate the functional and morphological changes in retina. We documented extensive vision loss due to photoreceptor degeneration, retinal ganglion cell and their axonal loss, retinal secondary neuronal and synaptic alternation, and Müller cell gliosis in the retina of MFN2 R94Q mice. Imbalanced MFN1/MFN2 ratio and dysregulated mitochondrial fusion/fission result in retinal degeneration via P62/LC3B-mediated mitophagy/autophagy in MFN2 R94Q mice. Finally, transgenic MFN1 augmentation (MFN2 R94Q :MFN1) rescued vision and retinal morphology to wild-type level via restoring homeostasis in mitochondrial MFN1/MFN2 ratio, fusion/fission cycle, and PINK1-dependent, Parkin-independent mitophagy.
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Affiliation(s)
- Saba Shahin
- Board of Governors Regenerative Medicine Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Bin Lu
- Board of Governors Regenerative Medicine Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Yueqin Zhou
- Board of Governors Regenerative Medicine Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Hui Xu
- Board of Governors Regenerative Medicine Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Jason Chetsawang
- Board of Governors Regenerative Medicine Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Robert H. Baloh
- Board of Governors Regenerative Medicine Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Shaomei Wang
- Board of Governors Regenerative Medicine Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- Corresponding author
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15
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Kulkarni PG, Mohire VM, Bhaisa PK, Joshi MM, Puranik CM, Waghmare PP, Banerjee T. Mitofusin-2: Functional switch between mitochondrial function and neurodegeneration. Mitochondrion 2023; 69:116-129. [PMID: 36764501 DOI: 10.1016/j.mito.2023.02.001] [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: 07/29/2022] [Revised: 01/07/2023] [Accepted: 02/04/2023] [Indexed: 02/11/2023]
Abstract
Mitochondria are highly dynamic organelles known to play role in the regulation of several cellular biological processes. However, their dynamics such as number, shape, and biological functions are regulated by mitochondrial fusion and fission process. The balance between the fusion and fission process is most important for the maintenance of mitochondrial structure as well as cellular functions. The alterations within mitochondrial dynamic processes were found to be associated with the progression of neurodegenerative diseases. In recent years, mitofusin-2 (Mfn2), a GTPase has emerged as a multifunctional protein which not only is found to regulate the mitochondrial fusion-fission process but also known to regulate several cellular functions such as mitochondrial metabolism, cellular biogenesis, signalling, and apoptosis via maintaining the ER-mitochondria contact sites. In this review, we summarize the current knowledge of the structural and functional properties of the Mfn2, its transcriptional regulation and their roles in several cellular functions with a focus on current advances in the pathogenesis of neurodegenerative diseases.
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Affiliation(s)
- Prakash G Kulkarni
- Department of Biotechnology, Savitribai Phule Pune University, Ganeshkhind Road, Pune 411007, India
| | - Vaibhavi M Mohire
- Molecular Neuroscience Research Centre, Dr. D. Y. Patil Biotechnology & Bioinformatics Institute, Dr. D. Y. Patil Vidyapeeth Survey No 87/88, Mumbai Bangalore Express Highway, Tathawade, Pune 411 033, India
| | - Pooja K Bhaisa
- Molecular Neuroscience Research Centre, Dr. D. Y. Patil Biotechnology & Bioinformatics Institute, Dr. D. Y. Patil Vidyapeeth Survey No 87/88, Mumbai Bangalore Express Highway, Tathawade, Pune 411 033, India
| | - Mrudula M Joshi
- Molecular Neuroscience Research Centre, Dr. D. Y. Patil Biotechnology & Bioinformatics Institute, Dr. D. Y. Patil Vidyapeeth Survey No 87/88, Mumbai Bangalore Express Highway, Tathawade, Pune 411 033, India
| | - Chitranshi M Puranik
- Molecular Neuroscience Research Centre, Dr. D. Y. Patil Biotechnology & Bioinformatics Institute, Dr. D. Y. Patil Vidyapeeth Survey No 87/88, Mumbai Bangalore Express Highway, Tathawade, Pune 411 033, India
| | - Pranjal P Waghmare
- Molecular Neuroscience Research Centre, Dr. D. Y. Patil Biotechnology & Bioinformatics Institute, Dr. D. Y. Patil Vidyapeeth Survey No 87/88, Mumbai Bangalore Express Highway, Tathawade, Pune 411 033, India
| | - Tanushree Banerjee
- Molecular Neuroscience Research Centre, Dr. D. Y. Patil Biotechnology & Bioinformatics Institute, Dr. D. Y. Patil Vidyapeeth Survey No 87/88, Mumbai Bangalore Express Highway, Tathawade, Pune 411 033, India; Infosys Ltd., SEZ unit VI, Plot No. 1, Rajiv Gandhi Infotech Park, Hinjawadi Phase I, Pune, Maharashtra 411057, India.
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16
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Zhang X, Wang L, Li B, Shi J, Xu J, Yuan M. Targeting Mitochondrial Dysfunction in Neurodegenerative Diseases: Expanding the Therapeutic Approaches by Plant-Derived Natural Products. Pharmaceuticals (Basel) 2023; 16:277. [PMID: 37259422 PMCID: PMC9961467 DOI: 10.3390/ph16020277] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 02/04/2023] [Accepted: 02/08/2023] [Indexed: 09/16/2023] Open
Abstract
Mitochondria are the primary source of energy production in neurons, supporting the high energy consumption of the nervous system. Inefficient and dysfunctional mitochondria in the central nervous system have been implicated in neurodegenerative diseases. Therefore, targeting mitochondria offers a new therapeutic opportunity for neurodegenerative diseases. Many recent studies have proposed that plant-derived natural products, as pleiotropic, safe, and readily obtainable sources of new drugs, potentially treat neurodegenerative diseases by targeting mitochondria. In this review, we summarize recent advances in targeting mitochondria in neurotherapeutics by employing plant-derived natural products. We discuss the mechanism of plant-derived natural products according to their mechanism of action on mitochondria in terms of regulating biogenesis, fusion, fission, bioenergetics, oxidative stress, calcium homeostasis, membrane potential, and mitochondrial DNA stability, as well as repairing damaged mitochondria. In addition, we discuss the potential perspectives and challenges in developing plant-derived natural products to target mitochondria, highlighting the clinical value of phytochemicals as feasible candidates for future neurotherapeutics.
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Affiliation(s)
- Xiaoyue Zhang
- State Key Laboratory of Biotherapy and Cancer Center, West China School of Basic Medical Sciences & Forensic Medicine, West China Hospital, Sichuan University, Collaborative Innovation Center for Biotherapy, Chengdu 610041, China
| | - Longqin Wang
- State Key Laboratory of Biotherapy and Cancer Center, West China School of Basic Medical Sciences & Forensic Medicine, West China Hospital, Sichuan University, Collaborative Innovation Center for Biotherapy, Chengdu 610041, China
| | - Bowen Li
- State Key Laboratory of Biotherapy and Cancer Center, West China School of Basic Medical Sciences & Forensic Medicine, West China Hospital, Sichuan University, Collaborative Innovation Center for Biotherapy, Chengdu 610041, China
| | - Jiayan Shi
- State Key Laboratory of Biotherapy and Cancer Center, West China School of Basic Medical Sciences & Forensic Medicine, West China Hospital, Sichuan University, Collaborative Innovation Center for Biotherapy, Chengdu 610041, China
| | - Jia Xu
- School of Medicine, Ningbo University, Ningbo 315211, China
| | - Minlan Yuan
- Mental Health Center of West China Hospital, Sichuan University, Chengdu 610041, China
- Huaxi Brain Research Center, West China Hospital of Sichuan University, Chengdu 610041, China
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17
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Mann JP, Duan X, Patel S, Tábara LC, Scurria F, Alvarez-Guaita A, Haider A, Luijten I, Page M, Protasoni M, Lim K, Virtue S, O'Rahilly S, Armstrong M, Prudent J, Semple RK, Savage DB. A mouse model of human mitofusin-2-related lipodystrophy exhibits adipose-specific mitochondrial stress and reduced leptin secretion. eLife 2023; 12:e82283. [PMID: 36722855 PMCID: PMC9937658 DOI: 10.7554/elife.82283] [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: 07/29/2022] [Accepted: 01/30/2023] [Indexed: 02/02/2023] Open
Abstract
Mitochondrial dysfunction has been reported in obesity and insulin resistance, but primary genetic mitochondrial dysfunction is generally not associated with these, arguing against a straightforward causal relationship. A rare exception, recently identified in humans, is a syndrome of lower body adipose loss, leptin-deficient severe upper body adipose overgrowth, and insulin resistance caused by the p.Arg707Trp mutation in MFN2, encoding mitofusin 2. How the resulting selective form of mitochondrial dysfunction leads to tissue- and adipose depot-specific growth abnormalities and systemic biochemical perturbation is unknown. To address this, Mfn2R707W/R707W knock-in mice were generated and phenotyped on chow and high fat diets. Electron microscopy revealed adipose-specific mitochondrial morphological abnormalities. Oxidative phosphorylation measured in isolated mitochondria was unperturbed, but the cellular integrated stress response was activated in adipose tissue. Fat mass and distribution, body weight, and systemic glucose and lipid metabolism were unchanged, however serum leptin and adiponectin concentrations, and their secretion from adipose explants were reduced. Pharmacological induction of the integrated stress response in wild-type adipocytes also reduced secretion of leptin and adiponectin, suggesting an explanation for the in vivo findings. These data suggest that the p.Arg707Trp MFN2 mutation selectively perturbs mitochondrial morphology and activates the integrated stress response in adipose tissue. In mice, this does not disrupt most adipocyte functions or systemic metabolism, whereas in humans it is associated with pathological adipose remodelling and metabolic disease. In both species, disproportionate effects on leptin secretion may relate to cell autonomous induction of the integrated stress response.
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Affiliation(s)
- Jake P Mann
- Wellcome Trust-MRC Institute of Metabolic Science, University of CambridgeCambridgeUnited Kingdom
| | - Xiaowen Duan
- Wellcome Trust-MRC Institute of Metabolic Science, University of CambridgeCambridgeUnited Kingdom
| | - Satish Patel
- Wellcome Trust-MRC Institute of Metabolic Science, University of CambridgeCambridgeUnited Kingdom
| | - Luis Carlos Tábara
- Medical Research Council Mitochondrial Biology Unit, University of CambridgeCambridgeUnited Kingdom
| | - Fabio Scurria
- Wellcome Trust-MRC Institute of Metabolic Science, University of CambridgeCambridgeUnited Kingdom
| | - Anna Alvarez-Guaita
- Wellcome Trust-MRC Institute of Metabolic Science, University of CambridgeCambridgeUnited Kingdom
| | - Afreen Haider
- Wellcome Trust-MRC Institute of Metabolic Science, University of CambridgeCambridgeUnited Kingdom
| | - Ineke Luijten
- Centre for Cardiovascular Science, University of EdinburghEdinburghUnited Kingdom
| | | | - Margherita Protasoni
- Medical Research Council Mitochondrial Biology Unit, University of CambridgeCambridgeUnited Kingdom
| | - Koini Lim
- Wellcome Trust-MRC Institute of Metabolic Science, University of CambridgeCambridgeUnited Kingdom
| | - Sam Virtue
- Wellcome Trust-MRC Institute of Metabolic Science, University of CambridgeCambridgeUnited Kingdom
| | - Stephen O'Rahilly
- Wellcome Trust-MRC Institute of Metabolic Science, University of CambridgeCambridgeUnited Kingdom
| | | | - Julien Prudent
- Medical Research Council Mitochondrial Biology Unit, University of CambridgeCambridgeUnited Kingdom
| | - Robert K Semple
- Centre for Cardiovascular Science, University of EdinburghEdinburghUnited Kingdom
- MRC Human Genetics Unit, University of EdinburghEdinburghUnited Kingdom
| | - David B Savage
- Wellcome Trust-MRC Institute of Metabolic Science, University of CambridgeCambridgeUnited Kingdom
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18
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Zanfardino P, Longo G, Amati A, Morani F, Picardi E, Girolamo F, Pafundi M, Cox SN, Manzari C, Tullo A, Doccini S, Santorelli FM, Petruzzella V. Mitofusin 2 mutation drives cell proliferation in Charcot-Marie-Tooth 2A fibroblasts. Hum Mol Genet 2023; 32:333-350. [PMID: 35994048 DOI: 10.1093/hmg/ddac201] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 08/12/2022] [Accepted: 08/16/2022] [Indexed: 01/20/2023] Open
Abstract
Dominant mutations in ubiquitously expressed mitofusin 2 gene (MFN2) cause Charcot-Marie-Tooth type 2A (CMT2A; OMIM 609260), an inherited sensory-motor neuropathy that affects peripheral nerve axons. Mitofusin 2 protein has been found to take part in mitochondrial fusion, mitochondria-endoplasmic reticulum tethering, mitochondrial trafficking along axons, mitochondrial quality control and various types of cancer, in which MFN2 has been indicated as a tumor suppressor gene. Discordant data on the mitochondrial altered phenotypes in patient-derived fibroblasts harboring MFN2 mutations and in animal models have been reported. We addressed some of these issues by focusing on mitochondria behavior during autophagy and mitophagy in fibroblasts derived from a CMT2AMFN2 patient with an MFN2650G > T/C217F mutation in the GTPase domain. This study investigated mitochondrial dynamics, respiratory capacity and autophagy/mitophagy, to tackle the multifaceted MFN2 contribution to CMT2A pathogenesis. We found that MFN2 mutated fibroblasts showed impairment of mitochondrial morphology, bioenergetics capacity, and impairment of the early stages of autophagy, but not mitophagy. Unexpectedly, transcriptomic analysis of mutated fibroblasts highlighted marked differentially expressed pathways related to cell population proliferation and extracellular matrix organization. We consistently found the activation of mTORC2/AKT signaling and accelerated proliferation in the CMT2AMFN2 fibroblasts. In conclusion, our evidence indicates that MFN2 mutation can positively drive cell proliferation in CMT2AMFN2 fibroblasts.
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Affiliation(s)
- Paola Zanfardino
- Department of Medical Basic Sciences, Neurosciences and Sense Organs, University of Bari Aldo Moro, 70124 Bari, Italy
| | - Giovanna Longo
- Department of Medical Basic Sciences, Neurosciences and Sense Organs, University of Bari Aldo Moro, 70124 Bari, Italy
| | - Alessandro Amati
- Department of Medical Basic Sciences, Neurosciences and Sense Organs, University of Bari Aldo Moro, 70124 Bari, Italy
| | - Federica Morani
- Department of Biology, University of Pisa, 56126 Pisa, Italy
| | - Ernesto Picardi
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, 70125 Bari, Italy.,Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, National Research Council, 70125 Bari, Italy
| | - Francesco Girolamo
- Department of Medical Basic Sciences, Neurosciences and Sense Organs, University of Bari Aldo Moro, 70124 Bari, Italy
| | - Mariella Pafundi
- Department of Medical Basic Sciences, Neurosciences and Sense Organs, University of Bari Aldo Moro, 70124 Bari, Italy
| | - Sharon N Cox
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, 70125 Bari, Italy
| | - Caterina Manzari
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, 70125 Bari, Italy
| | - Apollonia Tullo
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, National Research Council, 70125 Bari, Italy
| | - Stefano Doccini
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, 56128 Pisa, Italy
| | - Filippo M Santorelli
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, 56128 Pisa, Italy
| | - Vittoria Petruzzella
- Department of Medical Basic Sciences, Neurosciences and Sense Organs, University of Bari Aldo Moro, 70124 Bari, Italy
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19
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Evaluation of optical coherence tomography findings and visual evoked potentials in Charcot-Marie-Tooth disease. Int Ophthalmol 2023; 43:333-341. [PMID: 35953577 DOI: 10.1007/s10792-022-02452-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: 01/11/2022] [Accepted: 07/31/2022] [Indexed: 02/07/2023]
Abstract
PURPOSE To evaluate the spectral-domain optical coherence tomography (SD-OCT) findings and pattern visual evoked potential (VEP) in Charcot-Marie-Tooth (CMT) disease. METHODS Seventeen patients with CMT disease and 17 control subjects were included in the study. The patients were divided into two groups according to conduction velocity and inheritance pattern as demyelinating type (CMT 1) and axonal type (CMT 2). The average retinal nerve fiber layer (RNFL) thickness, RNFL thicknesses of all quadrants, and thicknesses of the ganglion cell layer complex (GCC) were measured using SD-OCT. Pattern VEP recordings were evaluated in both groups. RESULTS The average and four quadrants of RNFL thicknesses, and superior and inferior GCC thicknesses were significantly thinner in the CMT patients compared with healthy individuals, but there were no statistically significant differences between the CMT groups. There was a significant positive correlation between age and all RNFL and GCC thicknesses in the CMT 2 group and between age and RNFL thickness of the temporal quadrant in the CMT 1 group. P100 latencies were significantly delayed in the CMT groups compared with controls, and there were no significant differences in P100 latencies between the CMT groups (p < 0.001). VEP amplitudes were in normal ranges in the CMT groups. CONCLUSION This study showed that RNFL and GCC thicknesses were significantly reduced and VEP latencies were prolonged in patients with CMT with normal clinical examinations. Our results suggest that optic nerves may be affected more frequently in patients with CMT that is detected in clinical examinations.
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20
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Ng YS, McFarland R. Mitochondrial encephalomyopathy. HANDBOOK OF CLINICAL NEUROLOGY 2023; 195:563-585. [PMID: 37562887 DOI: 10.1016/b978-0-323-98818-6.00025-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Mitochondrial dysfunction, especially perturbation of oxidative phosphorylation and adenosine triphosphate (ATP) generation, disrupts cellular homeostasis and is a surprisingly frequent cause of central and peripheral nervous system pathology. Mitochondrial disease is an umbrella term that encompasses a host of clinical syndromes and features caused by in excess of 300 different genetic defects affecting the mitochondrial and nuclear genomes. Patients with mitochondrial disease can present at any age, ranging from neonatal onset to late adult life, with variable organ involvement and neurological manifestations including neurodevelopmental delay, seizures, stroke-like episodes, movement disorders, optic neuropathy, myopathy, and neuropathy. Until relatively recently, analysis of skeletal muscle biopsy was the focus of diagnostic algorithms, but step-changes in the scope and availability of next-generation sequencing technology and multiomics analysis have revolutionized mitochondrial disease diagnosis. Currently, there is no specific therapy for most types of mitochondrial disease, although clinical trials research in the field is gathering momentum. In that context, active management of epilepsy, stroke-like episodes, dystonia, brainstem dysfunction, and Parkinsonism are all the more important in improving patient quality of life and reducing mortality.
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Affiliation(s)
- Yi Shiau Ng
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom.
| | - Robert McFarland
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
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21
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Ceylan GG, Habiloğlu E, Çavdarlı B, Tuncez E, Bilen S, Köken ÖY, Gündüz CNS. High diagnostic yield with algorithmic molecular approach on hereditary neuropathies. REVISTA DA ASSOCIACAO MEDICA BRASILEIRA (1992) 2023; 69:233-239. [PMID: 36790232 PMCID: PMC9983476 DOI: 10.1590/1806-9282.20220929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 10/24/2022] [Indexed: 02/12/2023]
Abstract
OBJECTIVE Charcot-Marie-Tooth disease covers a group of inherited peripheral neuropathies. The aim of this study was to investigate the effect of targeted next-generation sequencing panels on the molecular diagnosis of Charcot-Marie-Tooth disease and its subtypes in routine clinical practice, and also to show the limitations and importance of next-generation sequencing in the diagnosis of Charcot-Marie-Tooth diseases. METHODS This is a retrospective study. Three different molecular methods (multiplex ligation probe amplification, next-generation sequencing, and whole-exome sequencing) were used to detect the mutations related to Charcot-Marie-Tooth disease. RESULTS In total, 64 patients (33 males and 31 females) with suspected Charcot-Marie-Tooth disease were analyzed for molecular etiology. In all, 25 (39%) patients were diagnosed by multiplex ligation probe amplification. With an extra 11 patients with normal PMP22 multiplex ligation probe amplification results that were consulted to our laboratory for further genetic analysis, a total of 50 patients underwent next-generation sequencing for targeted gene panels associated with Charcot-Marie-Tooth disease. Notably, 18 (36%) patients had pathogenic/likely pathogenic variants. Whole-exome sequencing was performed on five patients with normal next-generation sequencing results; the diagnostic yield by whole-exome sequencing was 80% and it was higher in the childhood group. CONCLUSION The molecular etiology in Charcot-Marie-Tooth disease patients can be determined according to pre-test evaluation, deciding the inheritance type with pedigree analysis, the clinical phenotype, and an algorithm for the genetic analysis. The presence of patients without a molecular diagnosis in all the literature suggests that there are new genes or mechanisms waiting to be discovered in the etiology of Charcot-Marie-Tooth disease.
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Affiliation(s)
- Gülay Güleç Ceylan
- Ankara City Hospital, Department of Medical Genetics - Ankara, Turkey.,Ankara Yıldırım Beyazıt Üniversitesi, Department of Medical Genetics - Ankara, Turkey
| | - Esra Habiloğlu
- Ankara City Hospital, Department of Medical Genetics - Ankara, Turkey
| | - Büşranur Çavdarlı
- Ankara City Hospital, Department of Medical Genetics - Ankara, Turkey
| | - Ebru Tuncez
- Ankara City Hospital, Department of Medical Genetics - Ankara, Turkey
| | - Sule Bilen
- Ankara City Hospital, Neurology Department - Ankara, Turkey
| | - Özlem Yayıcı Köken
- Akdeniz University, Medical Faculty, Department of Pediatrics, Division of Pediatric Neurology - Antalya, Turkey
| | - C Nur Semerci Gündüz
- Ankara City Hospital, Department of Medical Genetics - Ankara, Turkey.,Ankara Yıldırım Beyazıt Üniversitesi, Department of Medical Genetics - Ankara, Turkey
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22
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Salekeen R, Kyba M. Not young but still immature: a HIF-1α-mediated maturation checkpoint in regenerating muscle. J Clin Invest 2022; 132:165322. [PMID: 36453544 PMCID: PMC9711870 DOI: 10.1172/jci165322] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Muscle fibers express particular isoforms of contractile proteins, depending on the fiber's function and the organism's developmental stage. In the adult, after a muscle injury, newly generated fibers transition through embryonic and neonatal myosins, prior to selecting their distinctive adult myosin isoform. In this issue of the JCI, Wang et al. discover a checkpoint that regulates the neonatal-to-adult myosin isoform transition. They found that HIF-1α regulated this checkpoint, with elevated HIF-1α levels blocking progression, while HIF-1α knockout accelerated the transition. They further related these findings to centronuclear myopathy, a disease in which HIF-1α is similarly elevated and neonatal myosin expression is maintained. These findings highlight a maturation checkpoint that impacts the skeletal muscle regeneration following ischemic injury, providing a pharmacologically accessible pathway in injury and diseases such as centronuclear myopathy.
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Affiliation(s)
- Rahagir Salekeen
- Lillehei Heart Institute.,Biochemistry, Molecular Biology, and Biophysics Graduate Program and
| | - Michael Kyba
- Lillehei Heart Institute.,Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota, USA
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23
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Wang X, Jia Y, Zhao J, Lesner NP, Menezes CJ, Shelton SD, Venigalla SSK, Xu J, Cai C, Mishra P. A mitofusin 2/HIF1α axis sets a maturation checkpoint in regenerating skeletal muscle. J Clin Invest 2022; 132:e161638. [PMID: 36125902 PMCID: PMC9711883 DOI: 10.1172/jci161638] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 09/13/2022] [Indexed: 11/17/2022] Open
Abstract
A fundamental issue in regenerative medicine is whether there exist endogenous regulatory mechanisms that limit the speed and efficiency of the repair process. We report the existence of a maturation checkpoint during muscle regeneration that pauses myofibers at a neonatal stage. This checkpoint is regulated by the mitochondrial protein mitofusin 2 (Mfn2), the expression of which is activated in response to muscle injury. Mfn2 is required for growth and maturation of regenerating myofibers; in the absence of Mfn2, new myofibers arrested at a neonatal stage, characterized by centrally nucleated myofibers and loss of H3K27me3 repressive marks at the neonatal myosin heavy chain gene. A similar arrest at the neonatal stage was observed in infantile cases of human centronuclear myopathy. Mechanistically, Mfn2 upregulation suppressed expression of hypoxia-induced factor 1α (HIF1α), which is induced in the setting of muscle damage. Sustained HIF1α signaling blocked maturation of new myofibers at the neonatal-to-adult fate transition, revealing the existence of a checkpoint that delays muscle regeneration. Correspondingly, inhibition of HIF1α allowed myofibers to bypass the checkpoint, thereby accelerating the repair process. We conclude that skeletal muscle contains a regenerative checkpoint that regulates the speed of myofiber maturation in response to Mfn2 and HIF1α activity.
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Affiliation(s)
- Xun Wang
- Children’s Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Yuemeng Jia
- Children’s Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Jiawei Zhao
- Division of Hematology/Oncology, Boston Children’s Hospital, Boston, Massachusetts, USA
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Nicholas P. Lesner
- Children’s Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Cameron J. Menezes
- Children’s Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Spencer D. Shelton
- Children’s Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Siva Sai Krishna Venigalla
- Children’s Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Jian Xu
- Children’s Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Harold C. Simmons Comprehensive Cancer Center
- Hamon Center for Regenerative Science and Medicine
- Department of Pediatrics, and
| | - Chunyu Cai
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Prashant Mishra
- Children’s Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Harold C. Simmons Comprehensive Cancer Center
- Department of Pediatrics, and
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24
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Franco A, Dang X, Zhang L, Molinoff PB, Dorn GW. Mitochondrial Dysfunction and Pharmacodynamics of Mitofusin Activation in Murine Charcot-Marie-Tooth Disease Type 2A. J Pharmacol Exp Ther 2022; 383:137-148. [PMID: 36507849 PMCID: PMC9553116 DOI: 10.1124/jpet.122.001332] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 08/03/2022] [Indexed: 01/07/2023] Open
Abstract
Mitofusin (MFN) 1 and MFN2 are dynamin GTPase family mitochondrial proteins that mediate mitochondrial fusion requiring MFN conformational shifts, formation of macromolecular complexes on and between mitochondria, and GTP hydrolysis. Damaging MFN2 mutations cause an untreatable, largely pediatric progressive peripheral neuropathy, Charcot-Marie-Tooth (CMT) disease type 2A. We used small molecule allosteric mitofusin activators that promote MFN conformations favoring fusion to interrogate the effects of MFN2 conformation and GTPase activity on MFN2-mediated mitochondrial fusion and motility in vitro. We translated these findings in vivo by defining dose-dependent pharmacodynamic and disease-modifying effects of mitofusin activators in murine CMT2A. MFN2 catalytic GTPase activity and MFN2 conformational switching are essential for mitochondrial fusion, but the two processes are separate and dissociable. We report the first concentration-response relationships for mitofusin activators to stimulate mitochondrial transport through CMT2A neuronal axons, which is similar to their stimulation of mitochondrial fusion. In CMT2A mice, intermittent (daily short acting) and sustained (twice daily long acting) mitofusin activation were equally effective in reversing neuromuscular degeneration. Moreover, acute dose-dependent pharmacodynamic effects of mitofusin activators on mitochondrial transport through CMT2A neuronal axons anticipated those for long-term reversal of neurodegenerative phenotypes. A crossover study showed that CMT2A neuronal deficits recurred after mitofusin activators are discontinued, and revealed that CMT2A can be ameliorated by mitofusin activation even in old (>74 week) mice. These data add to our understanding of mitochondrial dysfunction induced by a CMT2A MFN2 GTPase mutation and provide additional information supporting the approach of pharmacological mitofusin activation in CMT2A. SIGNIFICANCE: This study interrogated the roles of MFN2 catalytic activity and allosteric activation on impaired mitochondrial fusion and neuronal transport as they impact an untreatable peripheral neuropathy caused by MFN2 mutations, Charcot-Marie-Tooth disease type 2A. The results mechanistically link mitochondrial fusion and motility to the relaxed MFN2 protein conformation and correction of mitochondrial abnormalities to in vivo reversal of neurodegeneration in murine CMT2A.
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Affiliation(s)
- Antonietta Franco
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri (A.F., X.D., L.Z., G.W.D.); Department of Cardiology, The First Affiliated Hospital of Xi'an Jiao Tong University, Xi'an, Shaanxi, China (X.D.); Mitochondria in Motion Inc., St. Louis, Missouri (L.Z.); and Department of Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania (P.B.M.)
| | - Xiawei Dang
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri (A.F., X.D., L.Z., G.W.D.); Department of Cardiology, The First Affiliated Hospital of Xi'an Jiao Tong University, Xi'an, Shaanxi, China (X.D.); Mitochondria in Motion Inc., St. Louis, Missouri (L.Z.); and Department of Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania (P.B.M.)
| | - Lihong Zhang
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri (A.F., X.D., L.Z., G.W.D.); Department of Cardiology, The First Affiliated Hospital of Xi'an Jiao Tong University, Xi'an, Shaanxi, China (X.D.); Mitochondria in Motion Inc., St. Louis, Missouri (L.Z.); and Department of Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania (P.B.M.)
| | - Perry B Molinoff
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri (A.F., X.D., L.Z., G.W.D.); Department of Cardiology, The First Affiliated Hospital of Xi'an Jiao Tong University, Xi'an, Shaanxi, China (X.D.); Mitochondria in Motion Inc., St. Louis, Missouri (L.Z.); and Department of Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania (P.B.M.)
| | - Gerald W Dorn
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri (A.F., X.D., L.Z., G.W.D.); Department of Cardiology, The First Affiliated Hospital of Xi'an Jiao Tong University, Xi'an, Shaanxi, China (X.D.); Mitochondria in Motion Inc., St. Louis, Missouri (L.Z.); and Department of Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania (P.B.M.)
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25
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Sharma G, Zaman M, Sabouny R, Joel M, Martens K, Martino D, de Koning AJ, Pfeffer G, Shutt TE. Characterization of a novel variant in the HR1 domain of MFN2 in a patient with ataxia, optic atrophy and sensorineural hearing loss. F1000Res 2022; 10:606. [PMID: 38274408 PMCID: PMC10808857 DOI: 10.12688/f1000research.53230.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/22/2022] [Indexed: 01/27/2024] Open
Abstract
Background: Pathogenic variants in MFN2 cause Charcot-Marie-Tooth disease (CMT) type 2A (CMT2A) and are the leading cause of the axonal subtypes of CMT. CMT2A is characterized by predominantly distal motor weakness and muscle atrophy, with highly variable severity and onset age. Notably, some MFN2 variants can also lead to other phenotypes such as optic atrophy, hearing loss and lipodystrophy. Despite the clear link between MFN2 and CMT2A, our mechanistic understanding of how dysfunction of the MFN2 protein causes human disease pathologies remains incomplete. This lack of understanding is due in part to the multiple cellular roles of MFN2. Though initially characterized for its role in mediating mitochondrial fusion, MFN2 also plays important roles in mediating interactions between mitochondria and other organelles, such as the endoplasmic reticulum and lipid droplets. Additionally, MFN2 is also important for mitochondrial transport, mitochondrial autophagy, and has even been implicated in lipid transfer. Though over 100 pathogenic MFN2 variants have been described to date, only a few have been characterized functionally, and even then, often only for one or two functions. Method: Several MFN2-mediated functions were characterized in fibroblast cells from a patient presenting with cerebellar ataxia, deafness, blindness, and diffuse cerebral and cerebellar atrophy, who harbours a novel homozygous MFN2 variant, D414V, which is found in a region of the HR1 domain of MFN2 where few pathogenic variants occur. Results: We found evidence for impairment of several MFN2-mediated functions. Consistent with reduced mitochondrial fusion, patient fibroblasts exhibited more fragmented mitochondrial networks and had reduced mtDNA copy number. Additionally, patient fibroblasts had reduced oxygen consumption, fewer mitochondrial-ER contacts, and altered lipid droplets that displayed an unusual perinuclear distribution. Conclusion: Overall, this work characterizes D414V as a novel variant in MFN2 and expands the phenotypic presentation of MFN2 variants to include cerebellar ataxia.
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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, Alberta, T2N 4N1, Canada
| | - Mashiat Zaman
- 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, Alberta, T2N 4N1, Canada
| | - Rasha Sabouny
- 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, Alberta, T2N 4N1, Canada
| | - Matthew Joel
- Department of Biochemistry & Molecular Biology, Cumming School of Medicine, Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
- Departments of Clinical Neurosciences and Medical Genetics, Cumming School of Medicine, University of Calgary, Hotchkiss Brain Institute, Alberta Child Health Research Institute, Calgary, Alberta, T2N 4N1, Canada
| | - Kristina Martens
- Departments of Clinical Neurosciences and Medical Genetics, Cumming School of Medicine, University of Calgary, Hotchkiss Brain Institute, Alberta Child Health Research Institute, Calgary, Alberta, T2N 4N1, Canada
| | - Davide Martino
- Department of Clinical Neurosciences, Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
| | - A.P. Jason de Koning
- Department of Biochemistry & Molecular Biology, Cumming School of Medicine, Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
| | - Gerald Pfeffer
- Departments of Clinical Neurosciences and Medical Genetics, Cumming School of Medicine, University of Calgary, Hotchkiss Brain Institute, Alberta Child Health Research Institute, Calgary, Alberta, 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, Alberta, T2N 4N1, Canada
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26
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Piperine Derivatives Enhance Fusion and Axonal Transport of Mitochondria by Activating Mitofusins. CHEMISTRY 2022. [DOI: 10.3390/chemistry4030047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Piperine (1-piperoylpiperidine) is the major pungent component of black pepper (Piper nigrum) and exhibits a spectrum of pharmacological activities. The molecular bases for many of piperine’s biological effects are incompletely defined. We noted that the chemical structure of piperine generally conforms to a pharmacophore model for small bioactive molecules that activate mitofusin (MFN)-mediated mitochondrial fusion. Piperine, but not its isomer chavicine, stimulated mitochondrial fusion in MFN-deficient cells with EC50 of ~8 nM. We synthesized piperine analogs having structural features predicted to optimize mitofusin activation and defined structure-activity relationships (SAR) in live-cell mitochondrial elongation assays. When optimal spacing was maintained between amide and aromatic groups the derivatives were potent mitofusin activators. Compared to the prototype phenylhexanamide mitofusin activator, 2, novel molecules containing the piperidine structure of piperine exhibited markedly enhanced passive membrane permeability with no loss of fusogenic potency. Lead compounds 5 and 8 enhanced mitochondrial motility in cultured murine Charcot-Marie-Tooth disease type 2A (CMT2A) neurons, but only 8 improved mitochondrial transport in sciatic nerve axons of CMT2A mice. Piperine analogs represent a new chemical class of mitofusin activators with potential pharmaceutical advantages.
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27
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Liu J, Yang J. Mitochondria-associated membranes: A hub for neurodegenerative diseases. Biomed Pharmacother 2022; 149:112890. [PMID: 35367757 DOI: 10.1016/j.biopha.2022.112890] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/24/2022] [Accepted: 03/24/2022] [Indexed: 11/02/2022] Open
Abstract
In eukaryotic cells, organelles could coordinate complex mechanisms of signaling transduction metabolism and gene expression through their functional interactions. The functional domain between ER and mitochondria, called mitochondria-associated membranes (MAM), is closely associated with various physiological functions including intracellular lipid transport, Ca2+ transfer, mitochondria function maintenance, and autophagosome formation. In addition, more evidence suggests that MAM modulate cellular functions in health and disease. Studies have also demonstrated the association of MAM with numerous diseases, including neurodegenerative diseases, cancer, viral infection, obesity, and diabetes. In fact, recent evidence revealed a close relationship of MAM with Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), amyotrophic lateral sclerosis (ALS), and other neurodegenerative diseases. In this view, elucidating the role of MAM in neurodegenerative diseases is particularly important. This review will focus the main tethering protein complexes of MAM and functions of MAM. Besides, the role of MAM in the regulation of neurodegenerative diseases and the potential molecular mechanisms is introduced to provide a new understanding of the pathogenesis of these diseases.
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Affiliation(s)
- Jinxuan Liu
- Department of Toxicology, School of Public Health, China Medical University, NO.77 Puhe road, Shenyang North New Area, Shenyang, 110122, People's Republic of China.
| | - Jinghua Yang
- Department of Toxicology, School of Public Health, China Medical University, NO.77 Puhe road, Shenyang North New Area, Shenyang, 110122, People's Republic of China.
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28
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Scheffer DDL, Garcia AA, Lee L, Mochly-Rosen D, Ferreira JCB. Mitochondrial Fusion, Fission, and Mitophagy in Cardiac Diseases: Challenges and Therapeutic Opportunities. Antioxid Redox Signal 2022; 36:844-863. [PMID: 35044229 PMCID: PMC9125524 DOI: 10.1089/ars.2021.0145] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Significance: Mitochondria play a critical role in the physiology of the heart by controlling cardiac metabolism, function, and remodeling. Accumulation of fragmented and damaged mitochondria is a hallmark of cardiac diseases. Recent Advances: Disruption of quality control systems that maintain mitochondrial number, size, and shape through fission/fusion balance and mitophagy results in dysfunctional mitochondria, defective mitochondrial segregation, impaired cardiac bioenergetics, and excessive oxidative stress. Critical Issues: Pharmacological tools that improve the cardiac pool of healthy mitochondria through inhibition of excessive mitochondrial fission, boosting mitochondrial fusion, or increasing the clearance of damaged mitochondria have emerged as promising approaches to improve the prognosis of heart diseases. Future Directions: There is a reasonable amount of preclinical evidence supporting the effectiveness of molecules targeting mitochondrial fission and fusion to treat cardiac diseases. The current and future challenges are turning these lead molecules into treatments. Clinical studies focusing on acute (i.e., myocardial infarction) and chronic (i.e., heart failure) cardiac diseases are needed to validate the effectiveness of such strategies in improving mitochondrial morphology, metabolism, and cardiac function. Antioxid. Redox Signal. 36, 844-863.
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Affiliation(s)
- Débora da Luz Scheffer
- Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Adriana Ann Garcia
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford University, Stanford, California, USA
| | - Lucia Lee
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford University, Stanford, California, USA
| | - Daria Mochly-Rosen
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford University, Stanford, California, USA
| | - Julio Cesar Batista Ferreira
- Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil.,Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford University, Stanford, California, USA
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29
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Abati E, Manini A, Velardo D, Del Bo R, Napoli L, Rizzo F, Moggio M, Bresolin N, Bellone E, Bassi MT, D'Angelo MG, Comi GP, Corti S. Clinical and genetic features of a cohort of patients with MFN2-related neuropathy. Sci Rep 2022; 12:6181. [PMID: 35418194 PMCID: PMC9008012 DOI: 10.1038/s41598-022-10220-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 04/05/2022] [Indexed: 11/09/2022] Open
Abstract
Charcot–Marie–Tooth disease type 2A (CMT2A) is a rare inherited axonal neuropathy caused by mutations in MFN2 gene, which encodes Mitofusin 2, a transmembrane protein of the outer mitochondrial membrane. We performed a cross-sectional analysis on thirteen patients carrying mutations in MFN2, from ten families, describing their clinical and genetic characteristics. Evaluated patients presented a variable age of onset and a wide phenotypic spectrum, with most patients presenting a severe phenotype. A novel heterozygous missense variant was detected, p.K357E. It is located at a highly conserved position and predicted as pathogenic by in silico tools. At a clinical level, the p.K357E carrier shows a severe sensorimotor axonal neuropathy. In conclusion, our work expands the genetic spectrum of CMT2A, disclosing a novel mutation and its related clinical effect, and provides a detailed description of the clinical features of a cohort of patients with MFN2 mutations. Obtaining a precise genetic diagnosis in affected families is crucial both for family planning and prenatal diagnosis, and in a therapeutic perspective, as we are entering the era of personalized therapy for genetic diseases.
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Affiliation(s)
- Elena Abati
- Department of Pathophysiology and Transplantation (DEPT), Dino Ferrari Centre, Neuroscience Section, Fondazione IRCCS Ca' Granda - Ospedale Maggiore Policlinico, University of Milan, Via Francesco Sforza 35, 20122, Milan, Italy. .,Neurology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
| | - Arianna Manini
- Department of Pathophysiology and Transplantation (DEPT), Dino Ferrari Centre, Neuroscience Section, Fondazione IRCCS Ca' Granda - Ospedale Maggiore Policlinico, University of Milan, Via Francesco Sforza 35, 20122, Milan, Italy
| | - Daniele Velardo
- Neurology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.,Neuromuscular and Rare Diseases Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Roberto Del Bo
- Neurology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Laura Napoli
- Neuromuscular and Rare Diseases Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Federica Rizzo
- Department of Pathophysiology and Transplantation (DEPT), Dino Ferrari Centre, Neuroscience Section, Fondazione IRCCS Ca' Granda - Ospedale Maggiore Policlinico, University of Milan, Via Francesco Sforza 35, 20122, Milan, Italy.,Neurology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Maurizio Moggio
- Department of Pathophysiology and Transplantation (DEPT), Dino Ferrari Centre, Neuroscience Section, Fondazione IRCCS Ca' Granda - Ospedale Maggiore Policlinico, University of Milan, Via Francesco Sforza 35, 20122, Milan, Italy.,Neuromuscular and Rare Diseases Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Nereo Bresolin
- Department of Pathophysiology and Transplantation (DEPT), Dino Ferrari Centre, Neuroscience Section, Fondazione IRCCS Ca' Granda - Ospedale Maggiore Policlinico, University of Milan, Via Francesco Sforza 35, 20122, Milan, Italy.,Neurology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Emilia Bellone
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (Dinogmi) - Medical Genetics, University of Genoa, Genoa, Italy
| | - Maria Teresa Bassi
- Laboratory of Molecular Biology, Scientific Institute IRCCS E. Medea, Bosisio Parini, Lecco, Italy
| | - Maria Grazia D'Angelo
- Neuromuscular Disorder Unit, Scientific Institute IRCCS E. Medea, Bosisio Parini, Lecco, Italy
| | - Giacomo Pietro Comi
- Department of Pathophysiology and Transplantation (DEPT), Dino Ferrari Centre, Neuroscience Section, Fondazione IRCCS Ca' Granda - Ospedale Maggiore Policlinico, University of Milan, Via Francesco Sforza 35, 20122, Milan, Italy.,Neurology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.,Neuromuscular and Rare Diseases Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Stefania Corti
- Department of Pathophysiology and Transplantation (DEPT), Dino Ferrari Centre, Neuroscience Section, Fondazione IRCCS Ca' Granda - Ospedale Maggiore Policlinico, University of Milan, Via Francesco Sforza 35, 20122, Milan, Italy.,Neurology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
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30
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Zaman M, Shutt TE. The Role of Impaired Mitochondrial Dynamics in MFN2-Mediated Pathology. Front Cell Dev Biol 2022; 10:858286. [PMID: 35399520 PMCID: PMC8989266 DOI: 10.3389/fcell.2022.858286] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 03/07/2022] [Indexed: 12/17/2022] Open
Abstract
The Mitofusin 2 protein (MFN2), encoded by the MFN2 gene, was first described for its role in mediating mitochondrial fusion. However, MFN2 is now recognized to play additional roles in mitochondrial autophagy (mitophagy), mitochondrial motility, lipid transfer, and as a tether to other organelles including the endoplasmic reticulum (ER) and lipid droplets. The tethering role of MFN2 is an important mediator of mitochondrial-ER contact sites (MERCs), which themselves have many important functions that regulate mitochondria, including calcium homeostasis and lipid metabolism. Exemplifying the importance of MFN2, pathogenic variants in MFN2 are established to cause the peripheral neuropathy Charcot-Marie-Tooth Disease Subtype 2A (CMT2A). However, the mechanistic basis for disease is not clear. Moreover, additional pathogenic phenotypes such as lipomatosis, distal myopathy, optic atrophy, and hearing loss, can also sometimes be present in patients with CMT2A. Given these variable patient phenotypes, and the many cellular roles played by MFN2, the mechanistic underpinnings of the cellular impairments by which MFN2 dysfunction leads to disease are likely to be complex. Here, we will review what is known about the various functions of MFN2 that are impaired by pathogenic variants causing CMT2A, with a specific emphasis on the ties between MFN2 variants and MERCs.
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Affiliation(s)
- Mashiat Zaman
- Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada
- Alberta Children’s Hospital Research Institute (ACHRI), Calgary, AB, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Timothy E. Shutt
- Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada
- Alberta Children’s Hospital Research Institute (ACHRI), Calgary, AB, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
- Department of Medical Genetics, University of Calgary, Calgary, AB, Canada
- *Correspondence: Timothy E. Shutt,
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31
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Markovinovic A, Greig J, Martín-Guerrero SM, Salam S, Paillusson S. Endoplasmic reticulum-mitochondria signaling in neurons and neurodegenerative diseases. J Cell Sci 2022; 135:274270. [PMID: 35129196 DOI: 10.1242/jcs.248534] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Recent advances have revealed common pathological changes in neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis with related frontotemporal dementia (ALS/FTD). Many of these changes can be linked to alterations in endoplasmic reticulum (ER)-mitochondria signaling, including dysregulation of Ca2+ signaling, autophagy, lipid metabolism, ATP production, axonal transport, ER stress responses and synaptic dysfunction. ER-mitochondria signaling involves specialized regions of ER, called mitochondria-associated membranes (MAMs). Owing to their role in neurodegenerative processes, MAMs have gained attention as they appear to be associated with all the major neurodegenerative diseases. Furthermore, their specific role within neuronal maintenance is being revealed as mutant genes linked to major neurodegenerative diseases have been associated with damage to these specialized contacts. Several studies have now demonstrated that these specialized contacts regulate neuronal health and synaptic transmission, and that MAMs are damaged in patients with neurodegenerative diseases. This Review will focus on the role of MAMs and ER-mitochondria signaling within neurons and how damage of the ER-mitochondria axis leads to a disruption of vital processes causing eventual neurodegeneration.
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Affiliation(s)
- Andrea Markovinovic
- Department of Basic and Clinical Neuroscience. Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9RX, UK
| | - Jenny Greig
- Department of Basic and Clinical Neuroscience. Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9RX, UK.,Inserm, Centre de Recherche en Transplantation et Immunologie, UMR 1064, ITUN, 44093, Nantes, France
| | - Sandra María Martín-Guerrero
- Department of Basic and Clinical Neuroscience. Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9RX, UK
| | - Shaakir Salam
- Department of Basic and Clinical Neuroscience. Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9RX, UK
| | - Sebastien Paillusson
- Department of Basic and Clinical Neuroscience. Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9RX, UK.,Université de Nantes, Inserm, TENS, The Enteric Nervous System in Gut and Brain Diseases, IMAD, Nantes, 1 rue Gaston Veil, 44035, Nantes, France
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32
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Nan H, Hata T, Fukao T, Fukao T, Chen W, Kurita T, Natori T, Takiyama Y. MFN2-related Charcot-Marie-Tooth Disease with Atypical Ocular Manifestations. Intern Med 2021; 60:3969-3974. [PMID: 34121014 PMCID: PMC8758439 DOI: 10.2169/internalmedicine.7463-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We herein describe a Charcot-Marie-Tooth disease (CMT) family with a MFN2 mutation with atypical ocular manifestations. The proband, his mother, his third daughter, and his deceased maternal grandfather all had symptoms of CMT and a visual impairment (either cataracts or severe astigmatism). On whole-exome sequencing for the proband having CMT and congenital cataracts, we identified a c.314C>T (p.Thr105Met) mutation in MFN2, but no mutation in the causative genes associated with cataracts. This missense mutation in MFN2 co-segregated with CMT and the atypical ocular manifestations in this family. The findings of this study might help to expand the clinical phenotype of heterogeneous MFN2-related CMT.
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Affiliation(s)
- Haitian Nan
- Department of Neurology, University of Yamanashi, Japan
| | - Takanori Hata
- Department of Neurology, University of Yamanashi, Japan
| | - Toko Fukao
- Department of Neurology, University of Yamanashi, Japan
| | | | - Wanjing Chen
- Department of Ophthalmology, University of Yamanashi, Japan
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33
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Ma Y, Sun A, Zhang Y, Fan D, Liu X. The Genotype and Phenotype Features in a Large Chinese MFN2 Mutation Cohort. Front Neurol 2021; 12:757518. [PMID: 34721278 PMCID: PMC8548668 DOI: 10.3389/fneur.2021.757518] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 09/09/2021] [Indexed: 12/24/2022] Open
Abstract
Introduction: Charcot–Marie–Tooth disease type 2A (CMT2A) is a group of clinically and genetically heterogeneous disorders, which is mostly caused by mutations of the mitofusin2 (MFN2) gene. As the genotype–phenotype characteristics of CMT2A were still incompletely understood, we further explored the spectrum of CMT2A variants in China and demonstrated their phenotypic diversities. Methods: A total of 402 index patients/families with CMT throughout Mainland China were enrolled in this study. Among them, we analyzed 20 unrelated index cases with CMT2A by Sanger sequencing, next-generation sequencing, or whole-exome sequencing. Detailed clinical and genetic features of CMT2A patients were collected and analyzed. Of note, de novo mutations were not rare in MFN2 gene; we compared the clinical features of patients from the de novo group with those from the non-de novo group. Results: We identified 20 MFN2 variants, occupying 5.0% of CMT. Most patients presented with early onset and moderate phenotype with abnormal gait and foot drop as the main complaints at onset. Pyramidal signs accounts for 31.6% (6/19) in all patients, which is not uncommon. Four novel variants (p.Tyr752*, c.475-2A>G, p.Val99Met, and p.Arg275_Gln276insArg) were identified in the cohort. Besides, de novo variants occupied 35.0% (7/20) in our study with a much earlier age at onset compared with those in the non-de novo group (p = 0.021). Conclusion: Chinese CMT2A is a predominant typical pure CMT2A, with early onset and mild to moderate phenotype. Given the high frequency of de novo MFN2 mutations, genetic study should be considered for patients with early onset and severe idiopathic axonal neuropathy.
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Affiliation(s)
- Yan Ma
- Department of Neurology, Peking University Third Hospital, Beijing, China.,Beijing Municipal Key Laboratory of Biomarker and Translational Research in Neurodegenerative Diseases, Beijing, China.,Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Peking University, Beijing, China
| | - Aping Sun
- Department of Neurology, Peking University Third Hospital, Beijing, China.,Beijing Municipal Key Laboratory of Biomarker and Translational Research in Neurodegenerative Diseases, Beijing, China.,Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Peking University, Beijing, China
| | - Yingshuang Zhang
- Department of Neurology, Peking University Third Hospital, Beijing, China.,Beijing Municipal Key Laboratory of Biomarker and Translational Research in Neurodegenerative Diseases, Beijing, China.,Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Peking University, Beijing, China
| | - Dongsheng Fan
- Department of Neurology, Peking University Third Hospital, Beijing, China.,Beijing Municipal Key Laboratory of Biomarker and Translational Research in Neurodegenerative Diseases, Beijing, China.,Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Peking University, Beijing, China
| | - Xiaoxuan Liu
- Department of Neurology, Peking University Third Hospital, Beijing, China.,Beijing Municipal Key Laboratory of Biomarker and Translational Research in Neurodegenerative Diseases, Beijing, China.,Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Peking University, Beijing, China
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34
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Yang K, Hu HY, Zhang J, Yan YS, Chen WQ, Liu Y, Sun YQ, Guo Q, Yin CH. Metabolic and biophysical study of the MFN2 Ile213Thr mutant causing Hereditary Motor and Sensory Neuropathy (HMSN). Am J Transl Res 2021; 13:11501-11512. [PMID: 34786076 PMCID: PMC8581889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 07/30/2021] [Indexed: 06/13/2023]
Abstract
Charcot-Marie-Tooth (CMT) 2A disease, a genetic axonal nervous lesion, results from MFN2 pathogenic variation, and this gene plays a pivotal role in mitochondrial dynamics and calcium signaling. However, the underlying mechanism linking MFN2 defect to progressive dying-back of peripheral nerves is still unclear. The present work focused on analyzing one CMT2A patient from multiple perspectives. Clinical and pathologic evaluation was initially conducted on the recruited case. Subsequently, Sanger sequencing and whole-exome sequencing (WES) were performed for genetic detection. To reveal the cell metabolic alteration caused by the identified variant, this study also established and transfected plasmid vectors in HEK293 cells and analyzed cell metabolites through liquid chromatography in combination with quadrupole time-of-flight tandem mass spectrometry (UPLC Q-TOF MS). Additionally, we completed structural modeling and molecular dynamic (MD) simulation to investigate the intramolecular impact of the variant. According to our results, the clinical and neuropathologic manifestations of the proband matched with the diagnosis of CMT. The causative variant MFN2: c.638T>C: (p.Ile213Thr) was identified through genetic analysis. Moreover, metabolic pathway enrichment results demonstrated that this variant significantly affected the metabolism of sphingolipids and glycerophospholipids. MD analysis indicated that this variant crippled the binding ability of MFN2 to GTP. Taken together, our study deduced preliminary clues for the underlying mechanism by which mutant MFN2 affects cell metabolism and provided a novel perspective to understand the cellular and molecular impacts of MFN2 variants.
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Affiliation(s)
- Kai Yang
- Prenatal Diagnosis Center, Beijing Obstetrics and Gynecology Hospital, Capital Medical UniversityBeijing, China
| | - Hua-Ying Hu
- Jiaen Genetics Laboratory, Beijing Jiaen HospitalBeijing 100191, China
| | - Jing Zhang
- Prenatal Diagnosis Center,Shijiazhuang Obstetrics and Gynecology HospitalShijiazhuang, Hebei, China
| | - You-Sheng Yan
- Prenatal Diagnosis Center, Beijing Obstetrics and Gynecology Hospital, Capital Medical UniversityBeijing, China
| | - Wen-Qi Chen
- Prenatal Diagnosis Center,Shijiazhuang Obstetrics and Gynecology HospitalShijiazhuang, Hebei, China
| | - Yan Liu
- Prenatal Diagnosis Center, Beijing Obstetrics and Gynecology Hospital, Capital Medical UniversityBeijing, China
| | - Yong-Qing Sun
- Prenatal Diagnosis Center, Beijing Obstetrics and Gynecology Hospital, Capital Medical UniversityBeijing, China
| | - Qing Guo
- Prenatal Diagnosis Center,Shijiazhuang Obstetrics and Gynecology HospitalShijiazhuang, Hebei, China
| | - Cheng-Hong Yin
- Prenatal Diagnosis Center, Beijing Obstetrics and Gynecology Hospital, Capital Medical UniversityBeijing, China
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35
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Pellino G, Faggioli R, Galuppi A, Leon A, Fusco C, Tugnoli V, Suppiej A. Mitofusin 2: The missing link between mtDNA maintenance defects and neurotransmitter disorders. Mitochondrion 2021; 61:159-164. [PMID: 34600155 DOI: 10.1016/j.mito.2021.09.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 09/01/2021] [Accepted: 09/27/2021] [Indexed: 02/07/2023]
Abstract
Mitofusin (MFN) 2 belongs to the large family of mitochondrial transmembrane GTPases and has a role in dynamic mitochondrial remodeling process governed by fusion and fission. MFN2 pathogenic variants classically cause Charcot-Marie-Tooth disease type 2A (CMT2A), the most common axonal form of CMT, but patients with complex and unusual phenotypes involving the central and peripheral nervous system have been described, with mitochondrial dysfunction proposed as the underlying pathogenic mechanism. Here, we report the first description of a neurochemical pattern of secondary alterations in the metabolism of biogenic amines linked to the de novo presence of the hotspot MFN2 pathogenic variant p.Arg104Trp. The infant presented a very early onset choreic movement disorder associated with severe axial hypotonia and fluctuating dystonia of limbs. The relationship between mitochondrial DNA (mtDNA) maintenance defects and dopaminergic neurotransmitter disorders, governed by MFN2, is discussed.
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Affiliation(s)
- Giuditta Pellino
- Pediatric Unit, Azienda USL Ferrara - Sant'Anna University Hospital of Ferrara, Ferrara, Italy.
| | - Raffaella Faggioli
- Department of Medical Sciences, Section of Pediatrics, University of Ferrara, Ferrara, Italy
| | - Anna Galuppi
- Child Neurology Unit, Azienda USL Ferrara, Ferrara, Italy
| | - Alberta Leon
- Research & Innovation Srl (R&I Genetics), Padova, Italy
| | - Carlo Fusco
- Child Neurology and Psychiatric Unit-Presidio Ospedaliero Santa Maria Nuova - AUSL - IRCCS of Reggio Emilia, Reggio Emilia, Italy
| | - Valeria Tugnoli
- Department of Neuroscience and Rehabilitation, Division of Neurology, Sant'Anna University Hospital of Ferrara, Ferrara, Italy
| | - Agnese Suppiej
- Department of Medical Sciences, Section of Pediatrics, University of Ferrara, Ferrara, Italy
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36
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Majorel-Beraud C, Baudou E, Walther-Louvier U, Espil-Taris C, Beze-Beyrie P, Cintas P, Rivier F, Cances C. Clinical Phenotype in an Early-Onset French Pediatric Population: Charcot-Marie-Tooth's Disease Type 2A. Neuropediatrics 2021; 52:351-357. [PMID: 33578441 DOI: 10.1055/s-0041-1723759] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Charcot-Marie-Tooth's disease type 2A (MCT2A), induced by mutation of the mitofusin 2 (MFN2) gene represents the main cause of MCT2. The aim of this study is to provide details of the clinical and electromyographic phenotype of MCT2A in a pediatric population. We conducted a French multicenter retrospective study, including all children with a genetic diagnosis of MCT2A. Thirteen MCT2A children were included with a beginning of symptoms before the age of 10 years ("early-onset group"). We report two new mutations: c.1070 A → T (p.Lys357.Met) and c.280 C → G (p.Arg94Gly). The evolution of the disease is marked by a fast worsening for three patients with loss of motor autonomy, while the evolution is relatively stable for eight patients. The group of early-onset MCT2A seems more heterogeneous than previously described, with a nonconstant severe phenotype.
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Affiliation(s)
- C Majorel-Beraud
- Unit of Pediatric Neurology, French Greater South-West Reference Center for Neuromuscular Diseases, Hôpital des Enfants, Toulouse University Hospital Center, Toulouse, France
| | - E Baudou
- Unit of Pediatric Neurology, French Greater South-West Reference Center for Neuromuscular Diseases, Hôpital des Enfants, Toulouse University Hospital Center, Toulouse, France
| | - U Walther-Louvier
- Unit of Pediatric Neurology, French Greater South-West Reference Center for Neuromuscular Diseases, Hôpital Gui de Chauliac, Montpellier University Hospital Center, Montpellier, France
| | - C Espil-Taris
- Unit of Pediatric Neurology, French Greater South-West Reference Center for Neuromuscular Diseases, Hôpital des Enfants, University Hospital Center Pellegrin, Bordeaux, France
| | - P Beze-Beyrie
- Unit of Pediatrics, Centre Hospitalier de Pau, Pau, France
| | - P Cintas
- Department of Neurology, Pierre Paul Riquet Hospital, University Hospital Center Purpan, Toulouse, France
| | - F Rivier
- Unit of Pediatric Neurology, French Greater South-West Reference Center for Neuromuscular Diseases, Hôpital Gui de Chauliac, Montpellier University Hospital Center, Montpellier, France
| | - C Cances
- Unit of Pediatric Neurology, French Greater South-West Reference Center for Neuromuscular Diseases, Hôpital des Enfants, Toulouse University Hospital Center, Toulouse, France
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37
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McCray BA, Scherer SS. Axonal Charcot-Marie-Tooth Disease: from Common Pathogenic Mechanisms to Emerging Treatment Opportunities. Neurotherapeutics 2021; 18:2269-2285. [PMID: 34606075 PMCID: PMC8804038 DOI: 10.1007/s13311-021-01099-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/28/2021] [Indexed: 01/12/2023] Open
Abstract
Inherited peripheral neuropathies are a genetically and phenotypically diverse group of disorders that lead to degeneration of peripheral neurons with resulting sensory and motor dysfunction. Genetic neuropathies that primarily cause axonal degeneration, as opposed to demyelination, are most often classified as Charcot-Marie-Tooth disease type 2 (CMT2) and are the focus of this review. Gene identification efforts over the past three decades have dramatically expanded the genetic landscape of CMT and revealed several common pathological mechanisms among various forms of the disease. In some cases, identification of the precise genetic defect and/or the downstream pathological consequences of disease mutations have yielded promising therapeutic opportunities. In this review, we discuss evidence for pathogenic overlap among multiple forms of inherited neuropathy, highlighting genetic defects in axonal transport, mitochondrial dynamics, organelle-organelle contacts, and local axonal protein translation as recurrent pathological processes in inherited axonal neuropathies. We also discuss how these insights have informed emerging treatment strategies, including specific approaches for single forms of neuropathy, as well as more general approaches that have the potential to treat multiple types of neuropathy. Such therapeutic opportunities, made possible by improved understanding of molecular and cellular pathogenesis and advances in gene therapy technologies, herald a new and exciting phase in inherited peripheral neuropathy.
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Affiliation(s)
- Brett A. McCray
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
| | - Steven S. Scherer
- Department of Neurology, The University of Pennsylvania, Philadelphia, PA 19104 USA
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38
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Emery JM, Ortiz RM. Mitofusin 2: A link between mitochondrial function and substrate metabolism? Mitochondrion 2021; 61:125-137. [PMID: 34536562 DOI: 10.1016/j.mito.2021.09.003] [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: 04/02/2021] [Revised: 08/22/2021] [Accepted: 09/13/2021] [Indexed: 01/18/2023]
Abstract
Mitochondria are dynamic, interactive organelles that connect cellular signaling and whole-cell homeostasis. This "mitochatting" allows the cell to receive information about the mitochondria's condition before accommodating energy demands. Mitofusin 2 (Mfn2), an outer mitochondrial membrane fusion protein specializes in mediating mitochondrial homeostasis. Early studies defined the biological significance of Mfn2, while latter studies highlighted its role in substrate metabolism. However, determining Mfn2 potential to contribute to energy homeostasis needs study. This review summarizes current literature on mitochondrial metabolic processes, dynamics, and evidence of interactions among Mfn2 and regulatory processes that may link Mfn2's role in maintaining mitochondrial function and substrate metabolism.
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Affiliation(s)
- Janna M Emery
- Department of Molecular and Cellular Biology, School of Natural Sciences, University of California, Merced, United States.
| | - Rudy M Ortiz
- Department of Molecular and Cellular Biology, School of Natural Sciences, University of California, Merced, United States
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39
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Dang X, Williams SB, Devanathan S, Franco A, Fu L, Bernstein PR, Walters D, Dorn GW. Pharmacophore-Based Design of Phenyl-[hydroxycyclohexyl] Cycloalkyl-Carboxamide Mitofusin Activators with Improved Neuronal Activity. J Med Chem 2021; 64:12506-12524. [PMID: 34415150 DOI: 10.1021/acs.jmedchem.1c00163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mitochondrial fragmentation from defective fusion or unopposed fission contributes to many neurodegenerative diseases. Small molecule mitofusin activators reverse mitochondrial fragmentation in vitro, promising a novel therapeutic approach. The first-in-class mitofusin activator, 2, has a short plasma t1/2 and limited neurological system bioavailability, conferring "burst activation". Here, pharmacophore-based rational redesign generated analogues of 2 incorporating cycloalkyl linker groups. A cyclopropyl-containing linker, 5, improved plasma and brain t1/2, increased nervous system bioavailability, and prolonged neuron pharmacodynamic effects. Functional and single-crystal X-ray diffraction studies of stereoisomeric analogues of 5 containing sulfur as a "heavy atom", 14A and 14B, showed that 5 biological activity resides in the trans-R/R configuration, 5B. Structural analysis revealed stereoselective interactions of 5 associated with its mimicry of MFN2 Val372, Met376, and His380 side chains. Modification of murine ALS phenotypes in vitro and in vivo supports advancement of 5B for neurological conditions that may benefit from sustained mitofusin activation.
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Affiliation(s)
- Xiawei Dang
- Department of Cardiology, The First Affiliated Hospital of Xi'an Jiao Tong University, Xi'an, Shaanxi 710061, China.,Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Sidney B Williams
- Mitochondria in Motion, Inc., 4340 Duncan Avenue, Suite 216, St. Louis, Missouri 63110, United States
| | - Sriram Devanathan
- Mitochondria in Motion, Inc., 4340 Duncan Avenue, Suite 216, St. Louis, Missouri 63110, United States
| | - Antonietta Franco
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Lijun Fu
- WuXi AppTec Co., Ltd., 666 Gaoxin Road, East Lake High-tech Development Zone, Wuhan, Hubei 430075, China
| | - Peter R Bernstein
- PharmaB LLC, 50 S. 16th Street, Unit 5201, Philadelphia, Pennsylvania 19102, United States
| | - Daniel Walters
- Crystal Pharmatech Inc., 3000 Eastpark Blvd., Ste 500B, Cranbury, New Jersey 08512, United States
| | - Gerald W Dorn
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, United States.,Mitochondria in Motion, Inc., 4340 Duncan Avenue, Suite 216, St. Louis, Missouri 63110, United States
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40
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Aung LHH, Jumbo JCC, Wang Y, Li P. Therapeutic potential and recent advances on targeting mitochondrial dynamics in cardiac hypertrophy: A concise review. MOLECULAR THERAPY. NUCLEIC ACIDS 2021; 25:416-443. [PMID: 34484866 PMCID: PMC8405900 DOI: 10.1016/j.omtn.2021.06.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Pathological cardiac hypertrophy begins as an adaptive response to increased workload; however, sustained hemodynamic stress will lead it to maladaptation and eventually cardiac failure. Mitochondria, being the powerhouse of the cells, can regulate cardiac hypertrophy in both adaptive and maladaptive phases; they are dynamic organelles that can adjust their number, size, and shape through a process called mitochondrial dynamics. Recently, several studies indicate that promoting mitochondrial fusion along with preventing mitochondrial fission could improve cardiac function during cardiac hypertrophy and avert its progression toward heart failure. However, some studies also indicate that either hyperfusion or hypo-fission could induce apoptosis and cardiac dysfunction. In this review, we summarize the recent knowledge regarding the effects of mitochondrial dynamics on the development and progression of cardiac hypertrophy with particular emphasis on the regulatory role of mitochondrial dynamics proteins through the genetic, epigenetic, and post-translational mechanisms, followed by discussing the novel therapeutic strategies targeting mitochondrial dynamic pathways.
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Affiliation(s)
- Lynn Htet Htet Aung
- Center for Molecular Genetics, Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao 266021, China.,Center for Bioinformatics, Institute for Translational Medicine, School of Basic Science, College of Medicine, Qingdao University, Qingdao 266021, China
| | - Juan Carlos Cueva Jumbo
- School of Preclinical Medicine, Nanobody Research Center, Guangxi Medical University, Nanning 530021, China
| | - Yin Wang
- Center for Molecular Genetics, Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao 266021, China
| | - Peifeng Li
- Center for Molecular Genetics, Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao 266021, China.,Center for Bioinformatics, Institute for Translational Medicine, School of Basic Science, College of Medicine, Qingdao University, Qingdao 266021, China
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Sharma G, Sabouny R, Joel M, Martens K, Martino D, de Koning AJ, Pfeffer G, Shutt TE. Characterization of a novel variant in the HR1 domain of MFN2 in a patient with ataxia, optic atrophy and sensorineural hearing loss. F1000Res 2021. [DOI: 10.12688/f1000research.53230.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Background: Pathogenic variants in MFN2 cause Charcot-Marie-Tooth disease (CMT) type 2A (CMT2A) and are the leading cause of the axonal subtypes of CMT. CMT2A is characterized by predominantly distal motor weakness and muscle atrophy, with highly variable severity and onset age. Notably, some MFN2 variants can also lead to other phenotypes such as optic atrophy, hearing loss and lipodystrophy. Despite the clear link between MFN2 and CMT2A, our mechanistic understanding of how dysfunction of the MFN2 protein causes human disease pathologies remains incomplete. This lack of understanding is due in part to the multiple cellular roles of MFN2. Though initially characterized for its role in mediating mitochondrial fusion, MFN2 also plays important roles in mediating interactions between mitochondria and other organelles, such as the endoplasmic reticulum and lipid droplets. Additionally, MFN2 is also important for mitochondrial transport, mitochondrial autophagy, and has even been implicated in lipid transfer. Though over 100 pathogenic MFN2 variants have been described to date, only a few have been characterized functionally, and even then, often only for one or two functions. Method: Several MFN2-mediated functions were characterized in fibroblast cells from a patient presenting with cerebellar ataxia, deafness, blindness, and diffuse cerebral and cerebellar atrophy, who harbours a novel homozygous MFN2 variant, D414V, which is found in a region of the HR1 domain of MFN2 where few pathogenic variants occur. Results: We found evidence for impairment of several MFN2-mediated functions. Consistent with reduced mitochondrial fusion, patient fibroblasts exhibited more fragmented mitochondrial networks and had reduced mtDNA copy number. Additionally, patient fibroblasts had reduced oxygen consumption, fewer mitochondrial-ER contacts, and altered lipid droplets that displayed an unusual perinuclear distribution. Conclusion: Overall, this work characterizes D414V as a novel variant in MFN2 and expands the phenotypic presentation of MFN2 variants to include cerebellar ataxia.
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Paß T, Wiesner RJ, Pla-Martín D. Selective Neuron Vulnerability in Common and Rare Diseases-Mitochondria in the Focus. Front Mol Biosci 2021; 8:676187. [PMID: 34295920 PMCID: PMC8290884 DOI: 10.3389/fmolb.2021.676187] [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: 03/04/2021] [Accepted: 06/08/2021] [Indexed: 12/12/2022] Open
Abstract
Mitochondrial dysfunction is a central feature of neurodegeneration within the central and peripheral nervous system, highlighting a strong dependence on proper mitochondrial function of neurons with especially high energy consumptions. The fitness of mitochondria critically depends on preservation of distinct processes, including the maintenance of their own genome, mitochondrial dynamics, quality control, and Ca2+ handling. These processes appear to be differently affected in common neurodegenerative diseases, such as Alzheimer’s and Parkinson’s disease, as well as in rare neurological disorders, including Huntington’s disease, Amyotrophic Lateral Sclerosis and peripheral neuropathies. Strikingly, particular neuron populations of different morphology and function perish in these diseases, suggesting that cell-type specific factors contribute to the vulnerability to distinct mitochondrial defects. Here we review the disruption of mitochondrial processes in common as well as in rare neurological disorders and its impact on selective neurodegeneration. Understanding discrepancies and commonalities regarding mitochondrial dysfunction as well as individual neuronal demands will help to design new targets and to make use of already established treatments in order to improve treatment of these diseases.
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Affiliation(s)
- Thomas Paß
- Center for Physiology and Pathophysiology, Institute of Vegetative Physiology, University of Cologne, Cologne, Germany
| | - Rudolf J Wiesner
- Center for Physiology and Pathophysiology, Institute of Vegetative Physiology, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - David Pla-Martín
- Center for Physiology and Pathophysiology, Institute of Vegetative Physiology, University of Cologne, Cologne, Germany
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Adebayo M, Singh S, Singh AP, Dasgupta S. Mitochondrial fusion and fission: The fine-tune balance for cellular homeostasis. FASEB J 2021; 35:e21620. [PMID: 34048084 PMCID: PMC8415099 DOI: 10.1096/fj.202100067r] [Citation(s) in RCA: 153] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 04/06/2021] [Accepted: 04/10/2021] [Indexed: 12/13/2022]
Abstract
Mitochondria are highly dynamic, maternally inherited cytoplasmic organelles, which fulfill cellular energy demand through the oxidative phosphorylation system. Besides, they play an active role in calcium and damage-associated molecular patterns signaling, amino acid, and lipid metabolism, and apoptosis. Thus, the maintenance of mitochondrial integrity and homeostasis is extremely critical, which is achieved through continual fusion and fission. Mitochondrial fusion allows the transfer of gene products between mitochondria for optimal functioning, especially under metabolic and environmental stress. On the other hand, fission is crucial for mitochondrial division and quality control. The imbalance between these two processes is associated with various ailments such as cancer, neurodegenerative and cardiovascular diseases. This review discusses the molecular mechanisms that control mitochondrial fusion and fission and how the disruption of mitochondrial dynamics manifests into various disease conditions.
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Affiliation(s)
- Mary Adebayo
- Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604
- Department of Pathology, College of Medicine, University of South Alabama, Mobile, AL 36617
| | - Seema Singh
- Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604
- Department of Pathology, College of Medicine, University of South Alabama, Mobile, AL 36617
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL 36688
| | - Ajay Pratap Singh
- Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604
- Department of Pathology, College of Medicine, University of South Alabama, Mobile, AL 36617
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL 36688
| | - Santanu Dasgupta
- Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604
- Department of Pathology, College of Medicine, University of South Alabama, Mobile, AL 36617
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL 36688
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Kirthi V, Perumbalath A, Brown E, Nevitt S, Petropoulos IN, Burgess J, Roylance R, Cuthbertson DJ, Jackson TL, Malik RA, Alam U. Prevalence of peripheral neuropathy in pre-diabetes: a systematic review. BMJ Open Diabetes Res Care 2021; 9:9/1/e002040. [PMID: 34006607 PMCID: PMC8137250 DOI: 10.1136/bmjdrc-2020-002040] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 01/26/2021] [Accepted: 02/22/2021] [Indexed: 12/14/2022] Open
Abstract
There is growing evidence of excess peripheral neuropathy in pre-diabetes. We aimed to determine its prevalence, including the impact of diagnostic methodology on prevalence rates, through a systematic review conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A comprehensive electronic bibliographic search was performed in MEDLINE, EMBASE, PubMed, Web of Science and the Cochrane Central Register of Controlled Trials from inception to June 1, 2020. Two reviewers independently selected studies, extracted data and assessed risk of bias. An evaluation was undertaken by method of neuropathy assessment. After screening 1784 abstracts and reviewing 84 full-text records, 29 studies (9351 participants) were included. There was a wide range of prevalence estimates (2%-77%, IQR: 6%-34%), but the majority of studies (n=21, 72%) reported a prevalence ≥10%. The three highest prevalence estimates of 77% (95% CI: 54% to 100%), 71% (95% CI: 55% to 88%) and 66% (95% CI: 53% to 78%) were reported using plantar thermography, multimodal quantitative sensory testing and nerve conduction tests, respectively. In general, studies evaluating small nerve fiber parameters yielded a higher prevalence of peripheral neuropathy. Due to a variety of study populations and methods of assessing neuropathy, there was marked heterogeneity in the prevalence estimates. Most studies reported a higher prevalence of peripheral neuropathy in pre-diabetes, primarily of a small nerve fiber origin, than would be expected in the background population. Given the marked rise in pre-diabetes, further consideration of targeting screening in this population is required. Development of risk-stratification tools may facilitate earlier interventions.
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Affiliation(s)
- Varo Kirthi
- Faculty of Life Sciences and Medicine, King's College London, London, UK
- Department of Ophthalmology, King's College Hospital NHS Foundation Trust, London, UK
| | - Anugraha Perumbalath
- Department of Cardiovascular & Metabolic Medicine, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Emily Brown
- Department of Cardiovascular & Metabolic Medicine, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Sarah Nevitt
- Department of Biostatistics, University of Liverpool, Liverpool, UK
| | | | - Jamie Burgess
- Department of Cardiovascular & Metabolic Medicine, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Rebecca Roylance
- Edge Hill University Library, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | - Daniel J Cuthbertson
- Department of Cardiovascular & Metabolic Medicine, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Timothy L Jackson
- Faculty of Life Sciences and Medicine, King's College London, London, UK
- Department of Ophthalmology, King's College Hospital NHS Foundation Trust, London, UK
| | - Rayaz A Malik
- Research Division, Weill Cornell Medicine, Doha, Qatar
- Division of Cardiovascular Sciences, University of Manchester, Manchester, UK
| | - Uazman Alam
- Department of Cardiovascular & Metabolic Medicine, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
- Division of Endocrinology, Diabetes & Gastroenterology, University of Manchester, Manchester, UK
- Pain Research Institute, University of Liverpool, Liverpool, UK
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45
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Bruhn H, Samuelsson K, Schober FA, Engvall M, Lesko N, Wibom R, Nennesmo I, Calvo-Garrido J, Press R, Stranneheim H, Freyer C, Wedell A, Wredenberg A. Novel Mutation m.10372A>G in MT-ND3 Causing Sensorimotor Axonal Polyneuropathy. NEUROLOGY-GENETICS 2021; 7:e566. [PMID: 33732874 PMCID: PMC7962437 DOI: 10.1212/nxg.0000000000000566] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 01/12/2021] [Indexed: 11/15/2022]
Abstract
Objective To investigate the pathogenicity of a novel MT-ND3 mutation identified in a patient with adult-onset sensorimotor axonal polyneuropathy and report the clinical, morphologic, and biochemical findings. Methods Clinical assessments and morphologic and biochemical investigations of skeletal muscle and cultured myoblasts from the patient were performed. Whole-genome sequencing (WGS) of DNA from skeletal muscle and Sanger sequencing of mitochondrial DNA (mtDNA) from both skeletal muscle and cultured myoblasts were performed. Heteroplasmic levels of mutated mtDNA in different tissues were quantified by last-cycle hot PCR. Results Muscle showed ragged red fibers, paracrystalline inclusions, a significant reduction in complex I (CI) respiratory chain (RC) activity, and decreased adenosine triphosphate (ATP) production for all substrates used by CI. Sanger sequencing of DNA from skeletal muscle detected a unique previously unreported heteroplasmic mutation in mtDNA encoded MT-ND3, coding for a subunit in CI. WGS confirmed the mtDNA mutation but did not detect any other mutation explaining the disease. Cultured myoblasts, however, did not carry the mutation, and RC activity measurements in myoblasts were normal. Conclusions We report a case with adult-onset sensorimotor axonal polyneuropathy caused by a novel mtDNA mutation in MT-ND3. Loss of heteroplasmy in blood, cultured fibroblasts and myoblasts from the patient, and normal measurement of RC activity of the myoblasts support pathogenicity of the mutation. These findings highlight the importance of mitochondrial investigations in patients presenting with seemingly idiopathic polyneuropathy, especially if muscle also is affected.
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Affiliation(s)
- Helene Bruhn
- Department of Medical Biochemistry and Biophysics (H.B., R.W., C.F., A. Wredenberg), Karolinska Institutet; Centre for Inherited Metabolic Diseases (H.B., R.W., C.F., M.E., N.L., H.S., A. Wedell, A. Wredenberg), Karolinska University Hospital; Department of Clinical Neuroscience (K.S., R.P.), Karolinska Institutet; Department of Neurology (K.S., R.P.), Karolinska University Hospital; Department of Molecular Medicine and Surgery (F.A.S., M.E., N.L., J.C.-G., H.S., A. Wedell), Karolinska Institutet; Department of Pathology (I.N.), Karolinska University Hospital; and Science for Life Laboratory (H.S.), Karolinska Institutet, Stockholm, Sweden
| | - Kristin Samuelsson
- Department of Medical Biochemistry and Biophysics (H.B., R.W., C.F., A. Wredenberg), Karolinska Institutet; Centre for Inherited Metabolic Diseases (H.B., R.W., C.F., M.E., N.L., H.S., A. Wedell, A. Wredenberg), Karolinska University Hospital; Department of Clinical Neuroscience (K.S., R.P.), Karolinska Institutet; Department of Neurology (K.S., R.P.), Karolinska University Hospital; Department of Molecular Medicine and Surgery (F.A.S., M.E., N.L., J.C.-G., H.S., A. Wedell), Karolinska Institutet; Department of Pathology (I.N.), Karolinska University Hospital; and Science for Life Laboratory (H.S.), Karolinska Institutet, Stockholm, Sweden
| | - Florian A Schober
- Department of Medical Biochemistry and Biophysics (H.B., R.W., C.F., A. Wredenberg), Karolinska Institutet; Centre for Inherited Metabolic Diseases (H.B., R.W., C.F., M.E., N.L., H.S., A. Wedell, A. Wredenberg), Karolinska University Hospital; Department of Clinical Neuroscience (K.S., R.P.), Karolinska Institutet; Department of Neurology (K.S., R.P.), Karolinska University Hospital; Department of Molecular Medicine and Surgery (F.A.S., M.E., N.L., J.C.-G., H.S., A. Wedell), Karolinska Institutet; Department of Pathology (I.N.), Karolinska University Hospital; and Science for Life Laboratory (H.S.), Karolinska Institutet, Stockholm, Sweden
| | - Martin Engvall
- Department of Medical Biochemistry and Biophysics (H.B., R.W., C.F., A. Wredenberg), Karolinska Institutet; Centre for Inherited Metabolic Diseases (H.B., R.W., C.F., M.E., N.L., H.S., A. Wedell, A. Wredenberg), Karolinska University Hospital; Department of Clinical Neuroscience (K.S., R.P.), Karolinska Institutet; Department of Neurology (K.S., R.P.), Karolinska University Hospital; Department of Molecular Medicine and Surgery (F.A.S., M.E., N.L., J.C.-G., H.S., A. Wedell), Karolinska Institutet; Department of Pathology (I.N.), Karolinska University Hospital; and Science for Life Laboratory (H.S.), Karolinska Institutet, Stockholm, Sweden
| | - Nicole Lesko
- Department of Medical Biochemistry and Biophysics (H.B., R.W., C.F., A. Wredenberg), Karolinska Institutet; Centre for Inherited Metabolic Diseases (H.B., R.W., C.F., M.E., N.L., H.S., A. Wedell, A. Wredenberg), Karolinska University Hospital; Department of Clinical Neuroscience (K.S., R.P.), Karolinska Institutet; Department of Neurology (K.S., R.P.), Karolinska University Hospital; Department of Molecular Medicine and Surgery (F.A.S., M.E., N.L., J.C.-G., H.S., A. Wedell), Karolinska Institutet; Department of Pathology (I.N.), Karolinska University Hospital; and Science for Life Laboratory (H.S.), Karolinska Institutet, Stockholm, Sweden
| | - Rolf Wibom
- Department of Medical Biochemistry and Biophysics (H.B., R.W., C.F., A. Wredenberg), Karolinska Institutet; Centre for Inherited Metabolic Diseases (H.B., R.W., C.F., M.E., N.L., H.S., A. Wedell, A. Wredenberg), Karolinska University Hospital; Department of Clinical Neuroscience (K.S., R.P.), Karolinska Institutet; Department of Neurology (K.S., R.P.), Karolinska University Hospital; Department of Molecular Medicine and Surgery (F.A.S., M.E., N.L., J.C.-G., H.S., A. Wedell), Karolinska Institutet; Department of Pathology (I.N.), Karolinska University Hospital; and Science for Life Laboratory (H.S.), Karolinska Institutet, Stockholm, Sweden
| | - Inger Nennesmo
- Department of Medical Biochemistry and Biophysics (H.B., R.W., C.F., A. Wredenberg), Karolinska Institutet; Centre for Inherited Metabolic Diseases (H.B., R.W., C.F., M.E., N.L., H.S., A. Wedell, A. Wredenberg), Karolinska University Hospital; Department of Clinical Neuroscience (K.S., R.P.), Karolinska Institutet; Department of Neurology (K.S., R.P.), Karolinska University Hospital; Department of Molecular Medicine and Surgery (F.A.S., M.E., N.L., J.C.-G., H.S., A. Wedell), Karolinska Institutet; Department of Pathology (I.N.), Karolinska University Hospital; and Science for Life Laboratory (H.S.), Karolinska Institutet, Stockholm, Sweden
| | - Javier Calvo-Garrido
- Department of Medical Biochemistry and Biophysics (H.B., R.W., C.F., A. Wredenberg), Karolinska Institutet; Centre for Inherited Metabolic Diseases (H.B., R.W., C.F., M.E., N.L., H.S., A. Wedell, A. Wredenberg), Karolinska University Hospital; Department of Clinical Neuroscience (K.S., R.P.), Karolinska Institutet; Department of Neurology (K.S., R.P.), Karolinska University Hospital; Department of Molecular Medicine and Surgery (F.A.S., M.E., N.L., J.C.-G., H.S., A. Wedell), Karolinska Institutet; Department of Pathology (I.N.), Karolinska University Hospital; and Science for Life Laboratory (H.S.), Karolinska Institutet, Stockholm, Sweden
| | - Rayomand Press
- Department of Medical Biochemistry and Biophysics (H.B., R.W., C.F., A. Wredenberg), Karolinska Institutet; Centre for Inherited Metabolic Diseases (H.B., R.W., C.F., M.E., N.L., H.S., A. Wedell, A. Wredenberg), Karolinska University Hospital; Department of Clinical Neuroscience (K.S., R.P.), Karolinska Institutet; Department of Neurology (K.S., R.P.), Karolinska University Hospital; Department of Molecular Medicine and Surgery (F.A.S., M.E., N.L., J.C.-G., H.S., A. Wedell), Karolinska Institutet; Department of Pathology (I.N.), Karolinska University Hospital; and Science for Life Laboratory (H.S.), Karolinska Institutet, Stockholm, Sweden
| | - Henrik Stranneheim
- Department of Medical Biochemistry and Biophysics (H.B., R.W., C.F., A. Wredenberg), Karolinska Institutet; Centre for Inherited Metabolic Diseases (H.B., R.W., C.F., M.E., N.L., H.S., A. Wedell, A. Wredenberg), Karolinska University Hospital; Department of Clinical Neuroscience (K.S., R.P.), Karolinska Institutet; Department of Neurology (K.S., R.P.), Karolinska University Hospital; Department of Molecular Medicine and Surgery (F.A.S., M.E., N.L., J.C.-G., H.S., A. Wedell), Karolinska Institutet; Department of Pathology (I.N.), Karolinska University Hospital; and Science for Life Laboratory (H.S.), Karolinska Institutet, Stockholm, Sweden
| | - Christoph Freyer
- Department of Medical Biochemistry and Biophysics (H.B., R.W., C.F., A. Wredenberg), Karolinska Institutet; Centre for Inherited Metabolic Diseases (H.B., R.W., C.F., M.E., N.L., H.S., A. Wedell, A. Wredenberg), Karolinska University Hospital; Department of Clinical Neuroscience (K.S., R.P.), Karolinska Institutet; Department of Neurology (K.S., R.P.), Karolinska University Hospital; Department of Molecular Medicine and Surgery (F.A.S., M.E., N.L., J.C.-G., H.S., A. Wedell), Karolinska Institutet; Department of Pathology (I.N.), Karolinska University Hospital; and Science for Life Laboratory (H.S.), Karolinska Institutet, Stockholm, Sweden
| | - Anna Wedell
- Department of Medical Biochemistry and Biophysics (H.B., R.W., C.F., A. Wredenberg), Karolinska Institutet; Centre for Inherited Metabolic Diseases (H.B., R.W., C.F., M.E., N.L., H.S., A. Wedell, A. Wredenberg), Karolinska University Hospital; Department of Clinical Neuroscience (K.S., R.P.), Karolinska Institutet; Department of Neurology (K.S., R.P.), Karolinska University Hospital; Department of Molecular Medicine and Surgery (F.A.S., M.E., N.L., J.C.-G., H.S., A. Wedell), Karolinska Institutet; Department of Pathology (I.N.), Karolinska University Hospital; and Science for Life Laboratory (H.S.), Karolinska Institutet, Stockholm, Sweden
| | - Anna Wredenberg
- Department of Medical Biochemistry and Biophysics (H.B., R.W., C.F., A. Wredenberg), Karolinska Institutet; Centre for Inherited Metabolic Diseases (H.B., R.W., C.F., M.E., N.L., H.S., A. Wedell, A. Wredenberg), Karolinska University Hospital; Department of Clinical Neuroscience (K.S., R.P.), Karolinska Institutet; Department of Neurology (K.S., R.P.), Karolinska University Hospital; Department of Molecular Medicine and Surgery (F.A.S., M.E., N.L., J.C.-G., H.S., A. Wedell), Karolinska Institutet; Department of Pathology (I.N.), Karolinska University Hospital; and Science for Life Laboratory (H.S.), Karolinska Institutet, Stockholm, Sweden
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Pipis M, Feely SME, Polke JM, Skorupinska M, Perez L, Shy RR, Laura M, Morrow JM, Moroni I, Pisciotta C, Taroni F, Vujovic D, Lloyd TE, Acsadi G, Yum SW, Lewis RA, Finkel RS, Herrmann DN, Day JW, Li J, Saporta M, Sadjadi R, Walk D, Burns J, Muntoni F, Ramchandren S, Horvath R, Johnson NE, Züchner S, Pareyson D, Scherer SS, Rossor AM, Shy ME, Reilly MM. Natural history of Charcot-Marie-Tooth disease type 2A: a large international multicentre study. Brain 2021; 143:3589-3602. [PMID: 33415332 PMCID: PMC7805791 DOI: 10.1093/brain/awaa323] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 07/28/2020] [Indexed: 01/02/2023] Open
Abstract
Mitofusin-2 (MFN2) is one of two ubiquitously expressed homologous proteins in eukaryote cells, playing a critical role in mitochondrial fusion. Mutations in MFN2 (most commonly autosomal dominant) cause Charcot-Marie-Tooth disease type 2A (CMT2A), the commonest axonal form of CMT, with significant allelic heterogeneity. Previous, moderately-sized, cross sectional genotype-phenotype studies of CMT2A have described the phenotypic spectrum of the disease, but longitudinal natural history studies are lacking. In this large multicentre prospective cohort study of 196 patients with dominant and autosomal recessive CMT2A, we present an in-depth genotype-phenotype study of the baseline characteristics of patients with CMT2A and longitudinal data (1–2 years) to describe the natural history. A childhood onset of autosomal dominant CMT2A is the most predictive marker of significant disease severity and is independent of the disease duration. When compared to adult onset autosomal dominant CMT2A, it is associated with significantly higher rates of use of ankle-foot orthoses, full-time use of wheelchair, dexterity difficulties and also has significantly higher CMT Examination Score (CMTESv2) and CMT Neuropathy Score (CMTNSv2) at initial assessment. Analysis of longitudinal data using the CMTESv2 and its Rasch-weighted counterpart, CMTESv2-R, show that over 1 year, the CMTESv2 increases significantly in autosomal dominant CMT2A (mean change 0.84 ± 2.42; two-tailed paired t-test P = 0.039). Furthermore, over 2 years both the CMTESv2 (mean change 0.97 ± 1.77; two-tailed paired t-test P = 0.003) and the CMTESv2-R (mean change 1.21 ± 2.52; two-tailed paired t-test P = 0.009) increase significantly with respective standardized response means of 0.55 and 0.48. In the paediatric CMT2A population (autosomal dominant and autosomal recessive CMT2A grouped together), the CMT Pediatric Scale increases significantly both over 1 year (mean change 2.24 ± 3.09; two-tailed paired t-test P = 0.009) and over 2 years (mean change 4.00 ± 3.79; two-tailed paired t-test P = 0.031) with respective standardized response means of 0.72 and 1.06. This cross-sectional and longitudinal study of the largest CMT2A cohort reported to date provides guidance for variant interpretation, informs prognosis and also provides natural history data that will guide clinical trial design.
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Affiliation(s)
- Menelaos Pipis
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Shawna M E Feely
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - James M Polke
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Mariola Skorupinska
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Laura Perez
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Rosemary R Shy
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Matilde Laura
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Jasper M Morrow
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Isabella Moroni
- Department of Pediatric Neurosciences, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Chiara Pisciotta
- Unit of Rare Neurodegenerative and Neurometabolic Diseases, Department of Clinical Neurosciences, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Franco Taroni
- Unit of Medical Genetics and Neurogenetics, Department of Diagnostics and Technology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Dragan Vujovic
- Department of Neurology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Thomas E Lloyd
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Gyula Acsadi
- Connecticut Children's Medical Center, Hartford, CT, USA
| | - Sabrina W Yum
- The Children's Hospital of Philadelphia, and Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Richard A Lewis
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Richard S Finkel
- Center for Experimental Neurotherapeutics, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - David N Herrmann
- Department of Neurology, University of Rochester, Rochester, NY, USA
| | - John W Day
- Department of Neurology, Stanford Health Care, Stanford, CA, USA
| | - Jun Li
- Department of Neurology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Mario Saporta
- Department of Neurology, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Reza Sadjadi
- Massachusetts General Hospital, Boston, Massachusetts, USA
| | - David Walk
- Department of Neurology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Joshua Burns
- University of Sydney School of Health Sciences and Children's Hospital at Westmead, Sydney, Australia
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, NIHR Biomedical Research Centre at UCL Great Ormond Street Institute of Child Health and Great Ormond Street Hospital, London, UK
| | | | - Rita Horvath
- Department of Clinical Neurosciences, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | | | - Stephan Züchner
- Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Davide Pareyson
- Unit of Rare Neurodegenerative and Neurometabolic Diseases, Department of Clinical Neurosciences, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Steven S Scherer
- Department of Neurology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Alexander M Rossor
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Michael E Shy
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Mary M Reilly
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
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Leal NS, Martins LM. Mind the Gap: Mitochondria and the Endoplasmic Reticulum in Neurodegenerative Diseases. Biomedicines 2021; 9:biomedicines9020227. [PMID: 33672391 PMCID: PMC7926795 DOI: 10.3390/biomedicines9020227] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 02/17/2021] [Accepted: 02/18/2021] [Indexed: 12/16/2022] Open
Abstract
The way organelles are viewed by cell biologists is quickly changing. For many years, these cellular entities were thought to be unique and singular structures that performed specific roles. However, in recent decades, researchers have discovered that organelles are dynamic and form physical contacts. In addition, organelle interactions modulate several vital biological functions, and the dysregulation of these contacts is involved in cell dysfunction and different pathologies, including neurodegenerative diseases. Mitochondria–ER contact sites (MERCS) are among the most extensively studied and understood juxtapositioned interorganelle structures. In this review, we summarise the major biological and ultrastructural dysfunctions of MERCS in neurodegeneration, with a particular focus on Alzheimer’s disease as well as Parkinson’s disease, amyotrophic lateral sclerosis and frontotemporal dementia. We also propose an updated version of the MERCS hypothesis in Alzheimer’s disease based on new findings. Finally, we discuss the possibility of MERCS being used as possible drug targets to halt cell death and neurodegeneration.
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48
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Schiavon CR, Shadel GS, Manor U. Impaired Mitochondrial Mobility in Charcot-Marie-Tooth Disease. Front Cell Dev Biol 2021; 9:624823. [PMID: 33598463 PMCID: PMC7882694 DOI: 10.3389/fcell.2021.624823] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 01/05/2021] [Indexed: 12/13/2022] Open
Abstract
Charcot-Marie-Tooth (CMT) disease is a progressive, peripheral neuropathy and the most commonly inherited neurological disorder. Clinical manifestations of CMT mutations are typically limited to peripheral neurons, the longest cells in the body. Currently, mutations in at least 80 different genes are associated with CMT and new mutations are regularly being discovered. A large portion of the proteins mutated in axonal CMT have documented roles in mitochondrial mobility, suggesting that organelle trafficking defects may be a common underlying disease mechanism. This review will focus on the potential role of altered mitochondrial mobility in the pathogenesis of axonal CMT, highlighting the conceptional challenges and potential experimental and therapeutic opportunities presented by this "impaired mobility" model of the disease.
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Affiliation(s)
- Cara R. Schiavon
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, United States
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, United States
| | - Gerald S. Shadel
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, United States
| | - Uri Manor
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, United States
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49
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Katti P, Rai M, Srivastava S, D'Silva P, Nongthomba U. Marf-mediated mitochondrial fusion is imperative for the development and functioning of indirect flight muscles (IFMs) in drosophila. Exp Cell Res 2021; 399:112486. [PMID: 33450208 DOI: 10.1016/j.yexcr.2021.112486] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 01/07/2021] [Accepted: 01/09/2021] [Indexed: 11/15/2022]
Abstract
Dynamic changes in mitochondrial shape and size are vital for mitochondrial health and for tissue development and function. Adult Drosophila indirect flight muscles contain densely packed mitochondria. We show here that mitochondrial fusion is critical during early muscle development (in pupa) and that silencing of the outer mitochondrial membrane fusion gene, Marf, in muscles results in smaller mitochondria that are functionally defective. This leads to abnormal muscle development resulting in muscle dysfunction in adult flies. However, post-developmental silencing of Marf has no obvious effects on mitochondrial and muscle phenotype in adult flies, indicating the importance of mitochondrial fusion during early muscle development.
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Affiliation(s)
- Prasanna Katti
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, 560 012, India.
| | - Mamta Rai
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, 560 012, India
| | - Shubhi Srivastava
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, India
| | - Patrick D'Silva
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, India
| | - Upendra Nongthomba
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, 560 012, India.
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50
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Genetic mechanisms of peripheral nerve disease. Neurosci Lett 2020; 742:135357. [PMID: 33249104 DOI: 10.1016/j.neulet.2020.135357] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/24/2020] [Accepted: 09/02/2020] [Indexed: 12/17/2022]
Abstract
Peripheral neuropathies of genetic etiology are a very diverse group of disorders manifesting either as non-syndromic inherited neuropathies without significant manifestations outside the peripheral nervous system, or as part of a systemic or syndromic genetic disorder. The former and most frequent group is collectively known as Charcot-Marie-Tooth disease (CMT), with prevalence as high as 1:2,500 world-wide, and has proven to be genetically highly heterogeneous. More than 100 different genes have been identified so far to cause various CMT forms, following all possible inheritance patterns. CMT causative genes belong to several common functional pathways that are essential for the integrity of the peripheral nerve. Their discovery has provided insights into the normal biology of axons and myelinating cells, and has highlighted the molecular mechanisms including both loss of function and gain of function effects, leading to peripheral nerve degeneration. Demyelinating neuropathies result from dysfunction of genes primarily affecting myelinating Schwann cells, while axonal neuropathies are caused by genes affecting mostly neurons and their long axons. Furthermore, mutation in genes expressed outside the nervous system, as in the case of inherited amyloid neuropathies, may cause peripheral neuropathy resulting from accumulation of β-structured amyloid fibrils in peripheral nerves in addition to various organs. Increasing insights into the molecular-genetic mechanisms have revealed potential therapeutic targets. These will enable the development of novel therapeutics for genetic neuropathies that remain, in their majority, without effective treatment.
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