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Hayes LH, Sadjadi R. Hereditary Neuropathies. Continuum (Minneap Minn) 2023; 29:1514-1537. [PMID: 37851041 DOI: 10.1212/con.0000000000001339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2023]
Abstract
OBJECTIVE This article provides an overview of hereditary neuropathies, describes the different hereditary neuropathy subtypes and the clinical approach to differentiating between them, and summarizes their clinical management. LATEST DEVELOPMENTS Increasingly available clinical genetic testing has broadened the clinical spectrum of hereditary neuropathy subtypes and demonstrated a significant overlap of phenotypes associated with a single gene. New subtypes such as SORD -related neuropathy and CANVAS (cerebellar ataxia, neuropathy, vestibular areflexia syndrome) have emerged. The optimization of clinical management has improved gait and motor function in the adult and pediatric populations. Novel therapeutic approaches are entering clinical trials. ESSENTIAL POINTS Hereditary neuropathies constitute a spectrum of peripheral nerve disorders with variable degrees of motor and sensory symptoms, patterns of involvement, and clinical courses.
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Yalcouyé A, Rebelo AP, Cissé L, Rives L, Bamba S, Cogan J, Esoh K, Diarra S, Ezell KM, Taméga A, Guinto CO, Dohrn MF, Hamid R, Fischbeck KH, Zuchner S, Landouré G. Novel variant in CADM3 causes Charcot-Marie-Tooth disease. Brain Commun 2023; 5:fcad227. [PMID: 38074074 PMCID: PMC10702457 DOI: 10.1093/braincomms/fcad227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 07/14/2023] [Accepted: 08/31/2023] [Indexed: 02/12/2024] Open
Abstract
CADM3 has been recently reported causing a rare axonal Charcot-Marie-Tooth disease in three independent Caucasian families carrying a recurrent change. We describe the first alternative causative mutation in CADM3 in a family from black African and also observed de novo in a patient of Caucasian ancestry. The disease inheritance was consistent with autosomal dominant and sporadic patterns, respectively. Eight patients and their relatives were enroled from both families. The mean age at diagnosis was 33.9 years, and walking difficulty was commonly the first symptom. Neurological examination showed distal muscle weakness and atrophy, sensory loss and foot and hand deformities. A high clinical variability was noted, but as seen in CADM3-associated neuropathy, symptoms were more pronounced in the arms in some patients. Nerve conduction studies showed no response in most of the examined nerves, and an axonal type of neuropathy, where recorded. Whole exome sequencing revealed a novel missense variant (c.1102G>T; Gly368Cys) in CADM3, segregating with the disease. Functional analyses showed a significant decrease in CADM3-Gly368Cys protein levels in the membrane and major structural changes in its predicted secondary structure. Therefore, we extend the genotype spectrum of CADM3, underlining the need for genetic studies in underrepresented populations like in Africa.
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Affiliation(s)
- Abdoulaye Yalcouyé
- Faculté de Médecine et d’Odontostomatologie, USTTB, Bamako, Mali
- Division of Human Genetics, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Adriana P Rebelo
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, USA
| | - Lassana Cissé
- Faculté de Médecine et d’Odontostomatologie, USTTB, Bamako, Mali
| | - Lynette Rives
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, USA
| | - Salia Bamba
- Faculté de Médecine et d’Odontostomatologie, USTTB, Bamako, Mali
| | - Joy Cogan
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, USA
| | - Kevin Esoh
- Division of Human Genetics, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Salimata Diarra
- Faculté de Médecine et d’Odontostomatologie, USTTB, Bamako, Mali
- Neurogenetics Branch, National Institutes of Neurological Disorders and Stroke, Bethesda, USA
| | - Kimberly M Ezell
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, USA
| | - Abdoulaye Taméga
- Faculté de Médecine et d’Odontostomatologie, USTTB, Bamako, Mali
| | - Cheick O Guinto
- Faculté de Médecine et d’Odontostomatologie, USTTB, Bamako, Mali
- Service de Neurologie, Centre Hospitalier Universitaire Point ‘G’, Bamako, Mali
| | - Maike F Dohrn
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, USA
- Department of Neurology, Medical Faculty RWTH Aachen University, Aachen, Germany
| | - Rizwan Hamid
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, USA
| | - Kenneth H Fischbeck
- Neurogenetics Branch, National Institutes of Neurological Disorders and Stroke, Bethesda, USA
| | - Stephan Zuchner
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, USA
| | - Guida Landouré
- Faculté de Médecine et d’Odontostomatologie, USTTB, Bamako, Mali
- Neurogenetics Branch, National Institutes of Neurological Disorders and Stroke, Bethesda, USA
- Service de Neurologie, Centre Hospitalier Universitaire Point ‘G’, Bamako, Mali
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Stavrou M, Kleopa KA. CMT1A current gene therapy approaches and promising biomarkers. Neural Regen Res 2023; 18:1434-1440. [PMID: 36571339 PMCID: PMC10075121 DOI: 10.4103/1673-5374.361538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Charcot-Marie-Tooth neuropathies (CMT) constitute a group of common but highly heterogeneous, non-syndromic genetic disorders affecting predominantly the peripheral nervous system. CMT type 1A (CMT1A) is the most frequent type and accounts for almost ~50% of all diagnosed CMT cases. CMT1A results from the duplication of the peripheral myelin protein 22 (PMP22) gene. Overexpression of PMP22 protein overloads the protein folding apparatus in Schwann cells and activates the unfolded protein response. This leads to Schwann cell apoptosis, dys- and de- myelination and secondary axonal degeneration, ultimately causing neurological disabilities. During the last decades, several different gene therapies have been developed to treat CMT1A. Almost all of them remain at the pre-clinical stage using CMT1A animal models overexpressing PMP22. The therapeutic goal is to achieve gene silencing, directly or indirectly, thereby reversing the CMT1A genetic mechanism allowing the recovery of myelination and prevention of axonal loss. As promising treatments are rapidly emerging, treatment-responsive and clinically relevant biomarkers are becoming necessary. These biomarkers and sensitive clinical evaluation tools will facilitate the design and successful completion of future clinical trials for CMT1A.
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Affiliation(s)
- Marina Stavrou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Kleopas A Kleopa
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics; Center for Neuromuscular Disorders, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
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4
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Berth SH, Lloyd TE. Disruption of axonal transport in neurodegeneration. J Clin Invest 2023; 133:168554. [PMID: 37259916 DOI: 10.1172/jci168554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023] Open
Abstract
Neurons are markedly compartmentalized, which makes them reliant on axonal transport to maintain their health. Axonal transport is important for anterograde delivery of newly synthesized macromolecules and organelles from the cell body to the synapse and for the retrograde delivery of signaling endosomes and autophagosomes for degradation. Dysregulation of axonal transport occurs early in neurodegenerative diseases and plays a key role in axonal degeneration. Here, we provide an overview of mechanisms for regulation of axonal transport; discuss how these mechanisms are disrupted in neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, Huntington's disease, hereditary spastic paraplegia, amyotrophic lateral sclerosis, and Charcot-Marie-Tooth disease; and discuss therapeutic approaches targeting axonal transport.
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A De Novo Sequence Variant in Barrier-to-Autointegration Factor Is Associated with Dominant Motor Neuronopathy. Cells 2023; 12:cells12060847. [PMID: 36980188 PMCID: PMC10099716 DOI: 10.3390/cells12060847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 02/23/2023] [Accepted: 02/26/2023] [Indexed: 03/12/2023] Open
Abstract
Barrier-to-autointegration factor (BAF) is an essential component of the nuclear lamina. Encoded by BANF1, this DNA binding protein contributes to the regulation of gene expression, cell cycle progression, and nuclear integrity. A rare recessive BAF variant, Ala12Thr, causes the premature aging syndrome, Néstor–Guillermo progeria syndrome (NGPS). Here, we report the first dominant pathogenic BAF variant, Gly16Arg, identified in a patient presenting with progressive neuromuscular weakness. Although disease variants carry nearby amino acid substitutions, cellular and biochemical properties are distinct. In contrast to NGPS, Gly16Arg patient fibroblasts show modest changes in nuclear lamina structure and increases in repressive marks associated with heterochromatin. Structural studies reveal that the Gly16Arg substitution introduces a salt bridge between BAF monomers, reducing the conformation ensemble available to BAF. We show that this structural change increases the double-stranded DNA binding affinity of BAF Gly16Arg. Together, our findings suggest that BAF Gly16Arg has an increased chromatin occupancy that leads to epigenetic changes and impacts nuclear functions. These observations provide a new example of how a missense mutation can change a protein conformational equilibrium to cause a dominant disease and extend our understanding of mechanisms by which BAF function impacts human health.
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Nelson JT, Gay SS, Diamond S, Gauger M, Singer RM. Warning Signs: Occult Diabetes and Dysglycemia in the Hand Surgery Patient Population. Hand (N Y) 2022:15589447221142893. [PMID: 36564989 DOI: 10.1177/15589447221142893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Diabetes mellitus often exists for many years prior to diagnosis, and very little is known about the role of the prediagnosis stage of metabolic impairment in contributing to hand and upper-extremity pathology. The goal of this study is to determine the prevalence of undiagnosed glucose dysregulation in patients presenting with the 2 most commonly treated conditions of the hand and wrist. METHODS A retrospective study was performed of hand surgery patients with no established diagnosis of prediabetes or diabetes referred for a 2-hour glucose tolerance test according to American Diabetes Association criteria. Patients were divided into 3 groups: peripheral neuropathies, trigger finger, and controls with various upper-extremity diagnoses. Rates of undiagnosed prediabetes and diabetes were compared between groups, including subgroup analysis of patients based on unilateral or bilateral presentation. Binary logistic regression analysis was also used to calculate odds ratios for multiple variables. RESULTS Patients with neuropathy had a significantly higher incidence of undiagnosed dysglycemia compared with the control group. Of those patients, 51.3% were prediabetic and 12.8% were diabetic. The control group had significantly lower rates. Within the bilateral neuropathy patients, 59.6% had prediabetes and 15.4% had diabetes, versus 34.6% with prediabetes and 7.7% with diabetes in the unilateral group. CONCLUSIONS Hand surgeons encounter a patient population with high rates of undiagnosed prediabetes and diabetes, with some presentations as much as 6 times higher than the general population. Certain patient presentations should prompt appropriate diagnostic testing and referral, especially those presenting with bilateral compression neuropathy and elevated body mass index.
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Jennings MJ, Kagiava A, Vendredy L, Spaulding EL, Stavrou M, Hathazi D, Grüneboom A, De Winter V, Gess B, Schara U, Pogoryelova O, Lochmüller H, Borchers CH, Roos A, Burgess RW, Timmerman V, Kleopa KA, Horvath R. NCAM1 and GDF15 are biomarkers of Charcot-Marie-Tooth disease in patients and mice. Brain 2022; 145:3999-4015. [PMID: 35148379 PMCID: PMC9679171 DOI: 10.1093/brain/awac055] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 11/22/2021] [Accepted: 12/15/2021] [Indexed: 02/02/2023] Open
Abstract
Molecular markers scalable for clinical use are critical for the development of effective treatments and the design of clinical trials. Here, we identify proteins in sera of patients and mouse models with Charcot-Marie-Tooth disease (CMT) with characteristics that make them suitable as biomarkers in clinical practice and therapeutic trials. We collected serum from mouse models of CMT1A (C61 het), CMT2D (GarsC201R, GarsP278KY), CMT1X (Gjb1-null), CMT2L (Hspb8K141N) and from CMT patients with genotypes including CMT1A (PMP22d), CMT2D (GARS), CMT2N (AARS) and other rare genetic forms of CMT. The severity of neuropathy in the patients was assessed by the CMT Neuropathy Examination Score (CMTES). We performed multitargeted proteomics on both sample sets to identify proteins elevated across multiple mouse models and CMT patients. Selected proteins and additional potential biomarkers, such as growth differentiation factor 15 (GDF15) and cell free mitochondrial DNA, were validated by ELISA and quantitative PCR, respectively. We propose that neural cell adhesion molecule 1 (NCAM1) is a candidate biomarker for CMT, as it was elevated in Gjb1-null, Hspb8K141N, GarsC201R and GarsP278KY mice as well as in patients with both demyelinating (CMT1A) and axonal (CMT2D, CMT2N) forms of CMT. We show that NCAM1 may reflect disease severity, demonstrated by a progressive increase in mouse models with time and a significant positive correlation with CMTES neuropathy severity in patients. The increase in NCAM1 may reflect muscle regeneration triggered by denervation, which could potentially track disease progression or the effect of treatments. We found that member proteins of the complement system were elevated in Gjb1-null and Hspb8K141N mouse models as well as in patients with both demyelinating and axonal CMT, indicating possible complement activation at the impaired nerve terminals. However, complement proteins did not correlate with the severity of neuropathy measured on the CMTES scale. Although the complement system does not seem to be a prognostic biomarker, we do show complement elevation to be a common disease feature of CMT, which may be of interest as a therapeutic target. We also identify serum GDF15 as a highly sensitive diagnostic biomarker, which was elevated in all CMT genotypes as well as in Hspb8K141N, Gjb1-null, GarsC201R and GarsP278KY mouse models. Although we cannot fully explain its origin, it may reflect increased stress response or metabolic disturbances in CMT. Further large and longitudinal patient studies should be performed to establish the value of these proteins as diagnostic and prognostic molecular biomarkers for CMT.
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Affiliation(s)
- Matthew J Jennings
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Alexia Kagiava
- Department of Neuroscience and Neuromuscular Disorders Centre, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Leen Vendredy
- Peripheral Neuropathy Research Group, Department of Biomedical Sciences, Institute Born Bunge, University of Antwerp, Antwerp, Belgium
| | - Emily L Spaulding
- The Jackson Laboratory, Bar Harbor, ME, USA
- Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME 04469, USA
| | - Marina Stavrou
- Department of Neuroscience and Neuromuscular Disorders Centre, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Denisa Hathazi
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Anika Grüneboom
- Leibniz-Institut für Analytische Wissenschaften—ISAS—e.V, Dortmund, Germany
| | - Vicky De Winter
- Peripheral Neuropathy Research Group, Department of Biomedical Sciences, Institute Born Bunge, University of Antwerp, Antwerp, Belgium
| | - Burkhard Gess
- Department of Neurology, University Hospital Aachen, Aachen, Germany
| | - Ulrike Schara
- Centre for Neuromuscular Disorders in Children, University of Duisburg-Essen, Essen, Germany
| | - Oksana Pogoryelova
- Directorate of Neurosciences, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals, NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Hanns Lochmüller
- Division of Neurology, Department of Medicine, The Ottawa Hospital, Brain and Mind Research Institute and Children’s Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
- Department of Neuropediatrics and Muscle Disorders, Medical Center–University of Freiburg, Faculty of Medicine, Freiburg, Germany
- CNAG-CRG, Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Christoph H Borchers
- Segal Cancer Proteomics Centre, Lady Davis Institute, Jewish General Hospital, McGill University, Montreal, Quebec, Canada
- Gerald Bronfman Department of Oncology, Jewish General Hospital, McGill University, Montreal, Quebec, Canada
- Center for Computational and Data-Intensive Science and Engineering, Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Andreas Roos
- Division of Neurology, Department of Medicine, The Ottawa Hospital, Brain and Mind Research Institute and Children’s Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
- Department of Neurology, Heimer Institute for Muscle Research, University Hospital Bergmannsheil, Ruhr University Bochum, Bochum, Germany
| | - Robert W Burgess
- The Jackson Laboratory, Bar Harbor, ME, USA
- Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME 04469, USA
| | - Vincent Timmerman
- Peripheral Neuropathy Research Group, Department of Biomedical Sciences, Institute Born Bunge, University of Antwerp, Antwerp, Belgium
| | - Kleopas A Kleopa
- Department of Neuroscience and Neuromuscular Disorders Centre, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Rita Horvath
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
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Yalcouyé A, Esoh K, Guida L, Wonkam A. Current profile of Charcot-Marie-Tooth disease in Africa: A systematic review. J Peripher Nerv Syst 2022; 27:100-112. [PMID: 35383421 PMCID: PMC9322329 DOI: 10.1111/jns.12489] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 01/17/2022] [Accepted: 02/25/2022] [Indexed: 12/21/2022]
Abstract
BACKGROUND AND AIMS Charcot-Marie-Tooth disease (CMT) is the most common inherited peripheral neuropathy characterised by a high clinical and genetic heterogeneity. While most cases were described in populations with Caucasian ancestry, genetic research on CMT in Africa is scant. Only a few cases of CMT have been reported, mainly from North Africa. The current study aimed to summarise available data on CMT in Africa, with emphasis on the epidemiological, clinical, and genetic features. METHODS We searched PubMed, Scopus, Web of Sciences, and the African Journal Online for articles published from the database inception until April 2021 using specific keywords. A total of 398 articles were screened, and 28 fulfilled our selection criteria. RESULTS A total of 107 families totalling 185 patients were reported. Most studies were reported from North Africa (n = 22). The demyelinating form of CMT was the commonest subtype, and the phenotype varied greatly between families, and one family (1%) of CMT associated with hearing impairment was reported. The inheritance pattern was autosomal recessive in 91.2% (n = 97/107) of families. CMT-associated variants were reported in 11 genes: LMNA, GDAP1, GJB1, MPZ, MTMR13, MTMR2, PRX, FGD4/FRABIN, PMP22, SH3TC2, and GARS. The most common genes reported are LMNA, GDAP1, and SH3TC2 and have been found mostly in Northern African populations. INTERPRETATION This study reveals that CMT is not rare in Africa, and describes the current clinical and genetic profile. The review emphasised the urgent need to invest in genetic research to inform counselling, prevention, and care for CMT in numerous settings on the continent.
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Affiliation(s)
- Abdoulaye Yalcouyé
- Faculté de Médecine et d'Odontostomatologie, USTTB, Bamako, Mali.,Division of Human Genetics, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Kevin Esoh
- Division of Human Genetics, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Landouré Guida
- Faculté de Médecine et d'Odontostomatologie, USTTB, Bamako, Mali.,Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, USA.,Service de Neurologie, Centre Hospitalier Universitaire du Point "G", Bamako, Mali
| | - Ambroise Wonkam
- Division of Human Genetics, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.,McKusick-Nathans Institute, and Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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9
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Stavrou M, Kagiava A, Choudury SG, Jennings MJ, Wallace LM, Fowler AM, Heslegrave A, Richter J, Tryfonos C, Christodoulou C, Zetterberg H, Horvath R, Harper SQ, Kleopa KA. A translatable RNAi-driven gene therapy silences PMP22/Pmp22 genes and improves neuropathy in CMT1A mice. J Clin Invest 2022; 132:159814. [PMID: 35579942 PMCID: PMC9246392 DOI: 10.1172/jci159814] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 05/12/2022] [Indexed: 11/17/2022] Open
Abstract
Charcot-Marie-Tooth disease type 1A (CMT1A), the most common inherited demyelinating peripheral neuropathy, is caused by PMP22 gene duplication. Overexpression of WT PMP22 in Schwann cells destabilizes the myelin sheath, leading to demyelination and ultimately to secondary axonal loss and disability. No treatments currently exist that modify the disease course. The most direct route to CMT1A therapy will involve reducing PMP22 to normal levels. To accomplish this, we developed a gene therapy strategy to reduce PMP22 using artificial miRNAs targeting human PMP22 and mouse Pmp22 mRNAs. Our lead therapeutic miRNA, miR871, was packaged into an adeno-associated virus 9 (AAV9) vector and delivered by lumbar intrathecal injection into C61-het mice, a model of CMT1A. AAV9-miR871 efficiently transduced Schwann cells in C61-het peripheral nerves and reduced human and mouse PMP22 mRNA and protein levels. Treatment at early and late stages of the disease significantly improved multiple functional outcome measures and nerve conduction velocities. Furthermore, myelin pathology in lumbar roots and femoral motor nerves was ameliorated. The treated mice also showed reductions in circulating biomarkers of CMT1A. Taken together, our data demonstrate that AAV9-miR871–driven silencing of PMP22 rescues a CMT1A model and provides proof of principle for treating CMT1A using a translatable gene therapy approach.
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Affiliation(s)
- Marina Stavrou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Alexia Kagiava
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Sarah G Choudury
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, United States of America
| | - Matthew J Jennings
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Lindsay M Wallace
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, United States of America
| | - Allison M Fowler
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, United States of America
| | - Amanda Heslegrave
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Jan Richter
- Department of Molecular Virology, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Christina Tryfonos
- Department of Molecular Virology, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Christina Christodoulou
- Department of Molecular Virology, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Henrik Zetterberg
- Institute of Laboratory Medicine, Göteborgs University, Göteborg, Sweden
| | - Rita Horvath
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Scott Q Harper
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, United States of America
| | - Kleopas A Kleopa
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
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10
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Concomitant MPZ and MFN2 Gene Variants and Charcot Marie Tooth Disease in a Boy: Clinical and Genetic Analysis—Literature Review. Case Rep Pediatr 2022; 2022:3793226. [PMID: 35449525 PMCID: PMC9017559 DOI: 10.1155/2022/3793226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 03/31/2022] [Accepted: 04/01/2022] [Indexed: 12/04/2022] Open
Abstract
Charcot- Marie- Tooth (CMT) disease includes a group of clinically and genetically heterogeneous neuropathic disorders with an estimated frequency of 1 on 2.500 individuals. CMTs are differently classified according to the age of onset, type of inheritance, and type of inheritance plus clinical features. For these disorders, more than 100 genes have been implicated as causal factors, with mutations in the PMP22 being one of the most common. The demyelinating type (CMT1) affects more than 30% of the CMTs patients and manifests with motor and sensory dysfunctions of the peripheral nervous system mainly starting with slow progressive weakness of the lower extremities. We report here a 12 year- old boy presenting with typical features of CMT1 type, hearing impairment, and inguinal hernia who at the next-generation sequence analysis displayed a concomitant presence of two variants: the c.233 C>T p.Ser 78Leu of the MPZ gene (NM_000530.6) characterized as pathogenetic and the c.1403 G>A p.Arg 468His of the MFN2 gene (NM_014874.3) characterized as VUS. Concomitant variant mutations in CMTs have been uncommonly reported. The role of these gene mutations on the clinical expression and a literature review on this topic is discussed.
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11
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Dittmer KE, Neeley C, Perrott MR, Reynolds E, Garrick DJ, Littlejohn MD. Pathology of the peripheral neuropathy Charcot-Marie-Tooth disease type 4H in Holstein Friesian cattle with a splice site mutation in FGD4. Vet Pathol 2022; 59:442-450. [PMID: 35300540 DOI: 10.1177/03009858221083041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Charcot-Marie-Tooth disease (CMT) is a hereditary sensory and motor peripheral neuropathy that is one of the most common inherited neurological diseases of humans and may be caused by mutations in a number of different genes. The subtype Charcot-Marie-Tooth disease type 4H (CMT4H) is caused by homozygous mutations in the FGD4 (FYVE, RhoGEF, and PH domain-containing 4) gene. A previous genome-wide association study involving 130,783 dairy cows found 6 novel variants, one of which was a homozygous splice site mutation in the FGD4 gene. Descendants of carriers were genotyped to identify 9 homozygous Holstein Friesian calves that were raised to maturity, of which 5 were euthanized and sampled for histopathology and electron microscopy at 2 and 2.5 years of age. Three control Holstein Friesian animals were raised with the calves and euthanized at the same time points. No macroscopic lesions consistent with CMT4H were seen at necropsy. Microscopically, peripheral nerves were hypercellular due to hyperplasia of S100-positive Schwann cells, and there was onion bulb formation, axonal degeneration with demyelination, and increased thickness of the endoneurium. On electron microscopy, decreased axonal density, onion bulb formations, myelin outfoldings, and increased numbers of mitochondria were present. These changes are consistent with those described in mouse models and humans with CMT4H, making these cattle a potential large animal model for CMT.
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Affiliation(s)
| | | | | | | | | | - Mathew D Littlejohn
- Massey University, Palmerston North, New Zealand.,Livestock Improvement Corporation, Hamilton, New Zealand
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12
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Murie M, Peng Y, Rigby MJ, Dieterich IA, Farrugia MA, Endresen A, Bhattacharyya A, Puglielli L. ATase inhibition rescues age-associated proteotoxicity of the secretory pathway. Commun Biol 2022; 5:173. [PMID: 35217767 PMCID: PMC8881600 DOI: 10.1038/s42003-022-03118-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 02/04/2022] [Indexed: 01/25/2023] Open
Abstract
Malfunction of autophagy contributes to the progression of many chronic age-associated diseases. As such, improving normal proteostatic mechanisms is an active target for biomedical research and a key focal area for aging research. Endoplasmic reticulum (ER)-based acetylation has emerged as a mechanism that ensures proteostasis within the ER by regulating the induction of ER specific autophagy. ER acetylation is ensured by two ER-membrane bound acetyltransferases, ATase1 and ATase2. Here, we show that ATase inhibitors can rescue ongoing disease manifestations associated with the segmental progeria-like phenotype of AT-1 sTg mice. We also describe a pipeline to reliably identify ATase inhibitors with promising druggability properties. Finally, we show that successful ATase inhibitors can rescue the proteopathy of a mouse model of Alzheimer's disease. In conclusion, our study proposes that ATase-targeting approaches might offer a translational pathway for many age-associated proteopathies affecting the ER/secretory pathway.
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Affiliation(s)
- Maeghan Murie
- grid.14003.360000 0001 2167 3675Department of Medicine, University of Wisconsin-Madison, Madison, WI USA ,grid.14003.360000 0001 2167 3675Waisman Center, University of Wisconsin-Madison, Madison, WI USA ,grid.14003.360000 0001 2167 3675Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI USA
| | - Yajing Peng
- grid.14003.360000 0001 2167 3675Department of Medicine, University of Wisconsin-Madison, Madison, WI USA ,grid.14003.360000 0001 2167 3675Waisman Center, University of Wisconsin-Madison, Madison, WI USA
| | - Michael J. Rigby
- grid.14003.360000 0001 2167 3675Department of Medicine, University of Wisconsin-Madison, Madison, WI USA ,grid.14003.360000 0001 2167 3675Waisman Center, University of Wisconsin-Madison, Madison, WI USA ,grid.14003.360000 0001 2167 3675Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI USA
| | - Inca A. Dieterich
- grid.14003.360000 0001 2167 3675Department of Medicine, University of Wisconsin-Madison, Madison, WI USA ,grid.14003.360000 0001 2167 3675Waisman Center, University of Wisconsin-Madison, Madison, WI USA ,grid.14003.360000 0001 2167 3675Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI USA
| | - Mark A. Farrugia
- grid.14003.360000 0001 2167 3675Department of Medicine, University of Wisconsin-Madison, Madison, WI USA ,grid.14003.360000 0001 2167 3675Waisman Center, University of Wisconsin-Madison, Madison, WI USA ,grid.17088.360000 0001 2150 1785Present Address: Mark A. Farrugia, Michigan State University, East Lansing, MI USA
| | - Andreas Endresen
- grid.14003.360000 0001 2167 3675Department of Medicine, University of Wisconsin-Madison, Madison, WI USA ,grid.14003.360000 0001 2167 3675Waisman Center, University of Wisconsin-Madison, Madison, WI USA
| | - Anita Bhattacharyya
- grid.14003.360000 0001 2167 3675Waisman Center, University of Wisconsin-Madison, Madison, WI USA ,grid.14003.360000 0001 2167 3675Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI USA
| | - Luigi Puglielli
- grid.14003.360000 0001 2167 3675Department of Medicine, University of Wisconsin-Madison, Madison, WI USA ,grid.14003.360000 0001 2167 3675Waisman Center, University of Wisconsin-Madison, Madison, WI USA ,Geriatric Research Education Clinical Center, Veterans Affairs Medical Center, Madison, WI USA
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13
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Abstract
Junctophilins (JPHs) comprise a family of structural proteins that connect the plasma membrane to intracellular organelles such as the endo/sarcoplasmic reticulum. Tethering of these membrane structures results in the formation of highly organized subcellular junctions that play important signaling roles in all excitable cell types. There are four JPH isoforms, expressed primarily in muscle and neuronal cell types. Each JPH protein consists of 6 'membrane occupation and recognition nexus' (MORN) motifs, a joining region connecting these to another set of 2 MORN motifs, a putative alpha-helical region, a divergent region exhibiting low homology between JPH isoforms, and a carboxy-terminal transmembrane region anchoring into the ER/SR membrane. JPH isoforms play essential roles in developing and maintaining subcellular membrane junctions. Conversely, inherited mutations in JPH2 cause hypertrophic or dilated cardiomyopathy, while trinucleotide expansions in the JPH3 gene cause Huntington Disease-Like 2. Loss of JPH1 protein levels can cause skeletal myopathy, while loss of cardiac JPH2 levels causes heart failure and atrial fibrillation, among other disease. This review will provide a comprehensive overview of the JPH gene family, phylogeny, and evolutionary analysis of JPH genes and other MORN domain proteins. JPH biogenesis, membrane tethering, and binding partners will be discussed, as well as functional roles of JPH isoforms in excitable cells. Finally, potential roles of JPH isoform deficits in human disease pathogenesis will be reviewed.
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Affiliation(s)
- Stephan E Lehnart
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, Department of Cardiology and Pneumology, Georg-August University Göttingen, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, Texas, United States; Departments of Molecular Physiology and Biophysics, Medicine (Cardiology), Pediatrics (Cardiology), Neuroscience, and Center for Space Medicine, Baylor College of Medicine, Houston, Texas, United States
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14
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Martinsen V, Kursula P. Multiple sclerosis and myelin basic protein: insights into protein disorder and disease. Amino Acids 2021; 54:99-109. [PMID: 34889995 PMCID: PMC8810476 DOI: 10.1007/s00726-021-03111-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 11/24/2021] [Indexed: 01/18/2023]
Abstract
Myelin basic protein (MBP) is an abundant protein in central nervous system (CNS) myelin. MBP has long been studied as a factor in the pathogenesis of the autoimmune neurodegenerative disease multiple sclerosis (MS). MS is characterized by CNS inflammation, demyelination, and axonal loss. One of the main theories on the pathogenesis of MS suggests that exposure to foreign antigens causes the activation of cross-reactive T cells in genetically susceptible individuals, with MBP being a possible autoantigen. While a direct role for MBP as a primary antigen in human MS is unclear, it is clear that MBP and its functions in myelin formation and long-term maintenance are linked to MS. This review looks at some key molecular characteristics of MBP and its relevance to MS, as well as the mechanisms of possible molecular mimicry between MBP and some viral antigens. We also discuss the use of serum anti-myelin antibodies as biomarkers for disease. MBP is a prime example of an apparently simple, but in fact biochemically and structurally complex molecule, which is closely linked to both normal nervous system development and neurodegenerative disease.
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Affiliation(s)
- Vebjørn Martinsen
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, 5020, Bergen, Norway
| | - Petri Kursula
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, 5020, Bergen, Norway. .,Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7, 90220, Oulu, Finland.
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15
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Kagiava A, Richter J, Tryfonos C, Leal-Julià M, Sargiannidou I, Christodoulou C, Bosch A, Kleopa KA. Efficacy of AAV serotypes to target Schwann cells after intrathecal and intravenous delivery. Sci Rep 2021; 11:23358. [PMID: 34857831 PMCID: PMC8640002 DOI: 10.1038/s41598-021-02694-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 11/18/2021] [Indexed: 12/20/2022] Open
Abstract
To optimize gene delivery to myelinating Schwann cells we compared clinically relevant AAV serotypes and injection routes. AAV9 and AAVrh10 vectors expressing either EGFP or the neuropathy-associated gene GJB1/Connexin32 (Cx32) under a myelin specific promoter were injected intrathecally or intravenously in wild type and Gjb1-null mice, respectively. Vector biodistribution in lumbar roots and sciatic nerves was higher in AAVrh10 injected mice while EGFP and Cx32 expression rates and levels were similar between the two serotypes. A gradient of biodistribution away from the injection site was seen with both intrathecal and intravenous delivery, while similar expression rates were achieved despite higher vector amounts injected intravenously. Quantified immune cells in relevant tissues were similar to non-injected littermates. Overall, AAV9 and AAVrh10 efficiently transduce Schwann cells throughout the peripheral nervous system with both clinically relevant routes of administration, although AAV9 and intrathecal injection may offer a more efficient approach for treating demyelinating neuropathies.
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Affiliation(s)
- A Kagiava
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 6 Iroon Avenue, P.O. Box 23462, 1683, Nicosia, Cyprus.
| | - J Richter
- Molecular Virology Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - C Tryfonos
- Molecular Virology Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - M Leal-Julià
- Department of Biochemistry and Molecular Biology, Institute of Neurosciences, Barcelona, Spain
- Unitat Mixta UAB-VHIR, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
| | - I Sargiannidou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 6 Iroon Avenue, P.O. Box 23462, 1683, Nicosia, Cyprus
| | - C Christodoulou
- Molecular Virology Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - A Bosch
- Department of Biochemistry and Molecular Biology, Institute of Neurosciences, Barcelona, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Bellaterra, Spain
- Unitat Mixta UAB-VHIR, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
| | - K A Kleopa
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 6 Iroon Avenue, P.O. Box 23462, 1683, Nicosia, Cyprus
- Center for Neuromuscular Diseases, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
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16
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Biondo ED, Spontarelli K, Ababioh G, Méndez L, Artigas P. Diseases caused by mutations in the Na +/K + pump α1 gene ATP1A1. Am J Physiol Cell Physiol 2021; 321:C394-C408. [PMID: 34232746 DOI: 10.1152/ajpcell.00059.2021] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Human cell survival requires function of the Na+/K+ pump; the heteromeric protein that hydrolyzes ATP to extrude Na+ and import K+ across the plasmalemma, thereby building and maintaining these ions' electrochemical gradients. Numerous dominant diseases caused by mutations in genes encoding for Na+/K+ pump catalytic (α) subunit isoforms highlight the importance of this protein. Here, we review literature describing disorders caused by missense mutations in ATP1A1, the gene encoding the ubiquitously expressed α1 isoform of the Na+/K+ pump. These various maladies include primary aldosteronism with secondary hypertension, an endocrine syndrome, Charcot-Marie-Tooth disease, a peripheral neuropathy, complex spastic paraplegia, another neuromuscular disorder, as well as hypomagnesemia accompanied by seizures and cognitive delay, a condition affecting the renal and central nervous systems. This article focuses on observed commonalities among these mutations' functional effects, as well as on the special characteristics that enable each particular mutation to exclusively affect a certain system, without affecting others. In this respect, it is clear how somatic mutations localized to adrenal adenomas increase aldosterone production without compromising other systems. However, it remains largely unknown how and why some but not all de novo germline or familial mutations (where the mutant must be expressed in numerous tissues) produce a specific disease and not the other diseases. We propose hypotheses to explain this observation and the approaches that we think will drive future research on these debilitating disorders to develop novel patient-specific treatments by combining the use of heterologous protein-expression systems, patient-derived pluripotent cells, and gene-edited cell and mouse models.
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Affiliation(s)
- Elisa D Biondo
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Kerri Spontarelli
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Giovanna Ababioh
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Lois Méndez
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Pablo Artigas
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas
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17
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Uusitalo M, Klenow MB, Laulumaa S, Blakeley MP, Simonsen AC, Ruskamo S, Kursula P. Human myelin protein P2: from crystallography to time-lapse membrane imaging and neuropathy-associated variants. FEBS J 2021; 288:6716-6735. [PMID: 34138518 DOI: 10.1111/febs.16079] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 06/10/2021] [Accepted: 06/16/2021] [Indexed: 12/11/2022]
Abstract
Peripheral myelin protein 2 (P2) is a fatty acid-binding protein expressed in vertebrate peripheral nervous system myelin, as well as in human astrocytes. Suggested functions of P2 include membrane stacking and lipid transport. Mutations in the PMP2 gene, encoding P2, are associated with Charcot-Marie-Tooth disease (CMT). Recent studies have revealed three novel PMP2 mutations in CMT patients. To shed light on the structure and function of these P2 variants, we used X-ray and neutron crystallography, small-angle X-ray scattering, circular dichroism spectroscopy, computer simulations and lipid binding assays. The crystal and solution structures of the I50del, M114T and V115A variants of P2 showed minor differences to the wild-type protein, whereas their thermal stability was reduced. Vesicle aggregation assays revealed no change in membrane stacking characteristics, while the variants showed altered fatty acid binding. Time-lapse imaging of lipid bilayers indicated formation of double-membrane structures induced by P2, which could be related to its function in stacking of two myelin membrane surfaces in vivo. In order to better understand the links between structure, dynamics and function, the crystal structure of perdeuterated P2 was refined from room temperature data using neutrons and X-rays, and the results were compared to simulations and cryocooled crystal structures. Our data indicate similar properties for all known human P2 CMT variants; while crystal structures are nearly identical, thermal stability and function of CMT variants are impaired. Our data provide new insights into the structure-function relationships and dynamics of P2 in health and disease.
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Affiliation(s)
- Maiju Uusitalo
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Finland
| | - Martin Berg Klenow
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense, Denmark
| | - Saara Laulumaa
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Finland.,European Spallation Source, Lund, Sweden
| | | | - Adam Cohen Simonsen
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense, Denmark
| | - Salla Ruskamo
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Finland
| | - Petri Kursula
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Finland.,Department of Biomedicine, University of Bergen, Norway
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18
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Stavrou M, Sargiannidou I, Georgiou E, Kagiava A, Kleopa KA. Emerging Therapies for Charcot-Marie-Tooth Inherited Neuropathies. Int J Mol Sci 2021; 22:6048. [PMID: 34205075 PMCID: PMC8199910 DOI: 10.3390/ijms22116048] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/29/2021] [Accepted: 05/31/2021] [Indexed: 12/12/2022] Open
Abstract
Inherited neuropathies known as Charcot-Marie-Tooth (CMT) disease are genetically heterogeneous disorders affecting the peripheral nerves, causing significant and slowly progressive disability over the lifespan. The discovery of their diverse molecular genetic mechanisms over the past three decades has provided the basis for developing a wide range of therapeutics, leading to an exciting era of finding treatments for this, until now, incurable group of diseases. Many treatment approaches, including gene silencing and gene replacement therapies, as well as small molecule treatments are currently in preclinical testing while several have also reached clinical trial stage. Some of the treatment approaches are disease-specific targeted to the unique disease mechanism of each CMT form, while other therapeutics target common pathways shared by several or all CMT types. As promising treatments reach the stage of clinical translation, optimal outcome measures, novel biomarkers and appropriate trial designs are crucial in order to facilitate successful testing and validation of novel treatments for CMT patients.
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Affiliation(s)
- Marina Stavrou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, Nicosia 2371, Cyprus; (M.S.); (I.S.); (E.G.); (A.K.)
| | - Irene Sargiannidou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, Nicosia 2371, Cyprus; (M.S.); (I.S.); (E.G.); (A.K.)
| | - Elena Georgiou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, Nicosia 2371, Cyprus; (M.S.); (I.S.); (E.G.); (A.K.)
| | - Alexia Kagiava
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, Nicosia 2371, Cyprus; (M.S.); (I.S.); (E.G.); (A.K.)
| | - Kleopas A. Kleopa
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, Nicosia 2371, Cyprus; (M.S.); (I.S.); (E.G.); (A.K.)
- Center for Neuromuscular Diseases, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, Nicosia 2371, Cyprus
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19
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Abstract
For decades, recycling of membrane proteins has been represented in figures by arrows between the "endosome" and the plasma membrane, but recently there has been an explosion in the understanding of the mechanisms and protein complexes required to facilitate protein recycling. Here, some key discoveries will be introduced, including assigning function to a number of recently recognized protein complexes and linking their function to protein recycling. Furthermore, the importance of lipid interactions and links to diseases and epithelial polarity will be summarized.
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Affiliation(s)
- Fiona J McDonald
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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