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Abrams CK, Lancaster E, Li JJ, Dungan G, Gong D, Scherer SS, Freidin MM. Knock-in mouse models for CMTX1 show a loss of function phenotype in the peripheral nervous system. Exp Neurol 2023; 360:114277. [PMID: 36403785 DOI: 10.1016/j.expneurol.2022.114277] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 10/28/2022] [Accepted: 11/16/2022] [Indexed: 11/20/2022]
Abstract
The X-linked form of Charcot-Marie-Tooth disease (CMTX1) is the second most common form of CMT. In this study we used CRISPR/Cas9 to develop new "knock-in" models of CMTX1 that are more representative of the spectrum of mutations seen with CMTX1 than the Cx32 knockout (KO) mouse model used previously. We compared mice of four genotypes - wild-type, Cx32KO, p.T55I, and p.R75W. Sciatic motor conduction velocity slowing was the most robust electrophysiologic indicator of neuropathy, showing reductions in the Cx32KO by 3 months and in the p.T55I and p.R75W mice by 6 months. At both 6 and 12 months, all three mutant genotypes showed reduced four limb and hind limb grip strength compared to WT mice. Performance on 6 and 12 mm width balance beams revealed deficits that were most pronounced at on the 6 mm balance beam at 6 months of age. There were pathological changes of myelinated axons in the femoral motor nerve in all three mutant lines by 3 months of age, and these became more pronounced at 6 and 12 months of age; sensory nerves (femoral sensory and the caudal nerve of the tail) appeared normal at all ages examined. Our results demonstrate that mice can be used to show the pathogenicity of human GJB1 mutations, and these new models for CMTX1 should facilitate the preclinical work for developing treatments for CMTX1.
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Affiliation(s)
- Charles K Abrams
- Department of Neurology and Rehabilitation, College of Medicine, University of Illinois at Chicago, 912 South Wood Street, Chicago, IL 60657, USA; Richard and Loan Hill Department of Biomedical Engineering, University of Illinois at Chicago, USA.
| | - Eunjoo Lancaster
- Department of Neurology, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA..
| | - Jian J Li
- Department of Neurology, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA..
| | - Gabriel Dungan
- Department of Neurology and Rehabilitation, College of Medicine, University of Illinois at Chicago, 912 South Wood Street, Chicago, IL 60657, USA
| | - David Gong
- Richard and Loan Hill Department of Biomedical Engineering, University of Illinois at Chicago, USA.
| | - Steven S Scherer
- Department of Neurology, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA..
| | - Mona M Freidin
- Department of Neurology and Rehabilitation, College of Medicine, University of Illinois at Chicago, 912 South Wood Street, Chicago, IL 60657, USA.
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Moss KR, Bopp TS, Johnson AE, Höke A. New evidence for secondary axonal degeneration in demyelinating neuropathies. Neurosci Lett 2021; 744:135595. [PMID: 33359733 PMCID: PMC7852893 DOI: 10.1016/j.neulet.2020.135595] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 10/31/2020] [Accepted: 12/19/2020] [Indexed: 12/28/2022]
Abstract
Development of peripheral nervous system (PNS) myelin involves a coordinated series of events between growing axons and the Schwann cell (SC) progenitors that will eventually ensheath them. Myelin sheaths have evolved out of necessity to maintain rapid impulse propagation while accounting for body space constraints. However, myelinating SCs perform additional critical functions that are required to preserve axonal integrity including mitigating energy consumption by establishing the nodal architecture, regulating axon caliber by organizing axonal cytoskeleton networks, providing trophic and potentially metabolic support, possibly supplying genetic translation materials and protecting axons from toxic insults. The intermediate steps between the loss of these functions and the initiation of axon degeneration are unknown but the importance of these processes provides insightful clues. Prevalent demyelinating diseases of the PNS include the inherited neuropathies Charcot-Marie-Tooth Disease, Type 1 (CMT1) and Hereditary Neuropathy with Liability to Pressure Palsies (HNPP) and the inflammatory diseases Acute Inflammatory Demyelinating Polyneuropathy (AIDP) and Chronic Inflammatory Demyelinating Polyneuropathy (CIDP). Secondary axon degeneration is a common feature of demyelinating neuropathies and this process is often correlated with clinical deficits and long-lasting disability in patients. There is abundant electrophysiological and histological evidence for secondary axon degeneration in patients and rodent models of PNS demyelinating diseases. Fully understanding the involvement of secondary axon degeneration in these diseases is essential for expanding our knowledge of disease pathogenesis and prognosis, which will be essential for developing novel therapeutic strategies.
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Affiliation(s)
- Kathryn R Moss
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Taylor S Bopp
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Anna E Johnson
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Ahmet Höke
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD, United States.
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3
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Blanco-Cantó ME, Patel N, Velasco-Aviles S, Casillas-Bajo A, Salas-Felipe J, García-Escrivá A, Díaz-Marín C, Cabedo H. Novel EGR2 variant that associates with Charcot-Marie-Tooth disease when combined with lipopolysaccharide-induced TNF-α factor T49M polymorphism. NEUROLOGY-GENETICS 2020; 6:e407. [PMID: 32337334 PMCID: PMC7164973 DOI: 10.1212/nxg.0000000000000407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 12/30/2019] [Indexed: 11/15/2022]
Abstract
Objective To identify novel genetic mechanisms causing Charcot-Marie-Tooth (CMT) disease. Methods We performed a next-generation sequencing study of 34 genes associated with CMT in a patient with peripheral neuropathy. Results We found a non-previously described mutation in EGR2 (p.P397H). P397H mutation is located within the loop that connects zinc fingers 2 and 3, a pivotal domain for the activity of this transcription factor. Using promoter activity luciferase assays, we found that this mutation promotes decreased transcriptional activity of EGR2. In this patient, we also found a previously described nonpathogenic polymorphism in lipopolysaccharide-induced TNF-α factor (LITAF) (p.T49M). We show that the p.T49M mutation decreases the steady-state levels of the LITAF protein in Schwann cells. Loss of function of LITAF has been shown to produce deregulation in the NRG1-erbB signaling, a pivotal pathway for EGR2 expression by Schwann cells. Surprisingly, our segregation study demonstrates that p.P397H mutation in EGR2 is not sufficient to produce CMT disease. Most notably, only those patients expressing simultaneously the LITAF T49M polymorphism develop peripheral neuropathy. Conclusions Our data support that the LITAF loss-of-function interferes with the expression of the transcriptional-deficient EGR2 P397H mutant hampering Schwann cell differentiation and suggest that in vivo both genes act in tandem to allow the proper development of myelin.
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Affiliation(s)
- Maria Empar Blanco-Cantó
- ISABIAL (FISABIO) (M.E.B.-C., N.P., S.V.-A., A.C.-B., C.D.-M., H.C.), Hospital General Universitario de Alicante; Instituto de Neurociencias de Alicante UMH-CSIC (N.P., S.V.-A., A.C.-B., H.C.), San Juan de Alicante, Spain; Hospital Marina Salud (J.S.-F.), Denia; and Hospital IMED Levante (A.G.-E.), Benidorm, Spain
| | - Nikiben Patel
- ISABIAL (FISABIO) (M.E.B.-C., N.P., S.V.-A., A.C.-B., C.D.-M., H.C.), Hospital General Universitario de Alicante; Instituto de Neurociencias de Alicante UMH-CSIC (N.P., S.V.-A., A.C.-B., H.C.), San Juan de Alicante, Spain; Hospital Marina Salud (J.S.-F.), Denia; and Hospital IMED Levante (A.G.-E.), Benidorm, Spain
| | - Sergio Velasco-Aviles
- ISABIAL (FISABIO) (M.E.B.-C., N.P., S.V.-A., A.C.-B., C.D.-M., H.C.), Hospital General Universitario de Alicante; Instituto de Neurociencias de Alicante UMH-CSIC (N.P., S.V.-A., A.C.-B., H.C.), San Juan de Alicante, Spain; Hospital Marina Salud (J.S.-F.), Denia; and Hospital IMED Levante (A.G.-E.), Benidorm, Spain
| | - Angeles Casillas-Bajo
- ISABIAL (FISABIO) (M.E.B.-C., N.P., S.V.-A., A.C.-B., C.D.-M., H.C.), Hospital General Universitario de Alicante; Instituto de Neurociencias de Alicante UMH-CSIC (N.P., S.V.-A., A.C.-B., H.C.), San Juan de Alicante, Spain; Hospital Marina Salud (J.S.-F.), Denia; and Hospital IMED Levante (A.G.-E.), Benidorm, Spain
| | - Juan Salas-Felipe
- ISABIAL (FISABIO) (M.E.B.-C., N.P., S.V.-A., A.C.-B., C.D.-M., H.C.), Hospital General Universitario de Alicante; Instituto de Neurociencias de Alicante UMH-CSIC (N.P., S.V.-A., A.C.-B., H.C.), San Juan de Alicante, Spain; Hospital Marina Salud (J.S.-F.), Denia; and Hospital IMED Levante (A.G.-E.), Benidorm, Spain
| | - Alexandre García-Escrivá
- ISABIAL (FISABIO) (M.E.B.-C., N.P., S.V.-A., A.C.-B., C.D.-M., H.C.), Hospital General Universitario de Alicante; Instituto de Neurociencias de Alicante UMH-CSIC (N.P., S.V.-A., A.C.-B., H.C.), San Juan de Alicante, Spain; Hospital Marina Salud (J.S.-F.), Denia; and Hospital IMED Levante (A.G.-E.), Benidorm, Spain
| | - Carmen Díaz-Marín
- ISABIAL (FISABIO) (M.E.B.-C., N.P., S.V.-A., A.C.-B., C.D.-M., H.C.), Hospital General Universitario de Alicante; Instituto de Neurociencias de Alicante UMH-CSIC (N.P., S.V.-A., A.C.-B., H.C.), San Juan de Alicante, Spain; Hospital Marina Salud (J.S.-F.), Denia; and Hospital IMED Levante (A.G.-E.), Benidorm, Spain
| | - Hugo Cabedo
- ISABIAL (FISABIO) (M.E.B.-C., N.P., S.V.-A., A.C.-B., C.D.-M., H.C.), Hospital General Universitario de Alicante; Instituto de Neurociencias de Alicante UMH-CSIC (N.P., S.V.-A., A.C.-B., H.C.), San Juan de Alicante, Spain; Hospital Marina Salud (J.S.-F.), Denia; and Hospital IMED Levante (A.G.-E.), Benidorm, Spain
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Diseases of connexins expressed in myelinating glia. Neurosci Lett 2019; 695:91-99. [DOI: 10.1016/j.neulet.2017.05.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 05/15/2017] [Accepted: 05/19/2017] [Indexed: 11/23/2022]
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Guimarães-Costa R, Iancu Ferfoglia R, Leonard-Louis S, Ziegler F, Magy L, Fournier E, Dubourg O, Bouche P, Maisonobe T, Lacour A, Moerman A, Latour P, Stojkovic T. Phenotypic spectrum of Charcot-Marie-Tooth disease due to LITAF/SIMPLE mutations: a study of 18 patients. Eur J Neurol 2017; 24:530-538. [PMID: 28211240 DOI: 10.1111/ene.13239] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 11/30/2016] [Indexed: 01/11/2023]
Abstract
BACKGROUND AND PURPOSE Charcot-Marie-Tooth (CMT) 1C due to mutations in LITAF/SIMPLE is a rare subtype amongst the autosomal dominant demyelinating forms of CMT. Our objective was to report the clinical and electrophysiological characteristics of 18 CMT1C patients and compare them to 20 patients with PMP22 mutations: 10 CMT1A patients and 10 patients with hereditary neuropathy with liability to pressure palsies (HNPP). METHODS Charcot-Marie-Tooth 1C patients were followed-up in referral centres for neuromuscular diseases or were identified by familial survey. All CMT1A and HNPP patients were recruited at the referral centre for neuromuscular diseases of Pitié-Salpêtrière Hospital. RESULTS Two phenotypes were identified amongst 18 CMT1C patients: the classical CMT form ('CMT-like', 11 cases) and a predominantly sensory form ('sensory form', seven cases). The mean CMT neuropathy score was 4.45 in CMT1C patients. Motor nerve conduction velocities in the upper limbs were significantly more reduced in CMT1A than in CMT1C patients. On the other hand, the motor nerve conduction velocity of the median nerve was significantly lower in CMT1C compared to the HNPP group. Distal motor latency was significantly more prolonged in CMT1A patients compared to the CMT1C and HNPP groups, the latter two groups having similar distal motor latency values. Molecular analysis revealed five new LITAF/SIMPLE mutations (Ala111Thr, Gly112Ala, Trp116Arg, Pro135Leu, Arg160Cys). CONCLUSIONS Our study delineates CMT1C as mostly a mild form of neuropathy, and gives clinical and electrophysiological clues differentiating CMT1C from CMT1A and HNPP. Delineating phenotypes in CMT subtypes is important to orient molecular diagnosis and to help to interpret complex molecular findings.
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Affiliation(s)
- R Guimarães-Costa
- Centre de Référence des Maladies Neuromusculaires Paris Est, Institut de Myologie, Hôpital Pitié-Salpêtrière, Paris, France
| | - R Iancu Ferfoglia
- Centre de Référence des Maladies Neuromusculaires Paris Est, Institut de Myologie, Hôpital Pitié-Salpêtrière, Paris, France
| | - S Leonard-Louis
- Centre de Référence des Maladies Neuromusculaires Paris Est, Institut de Myologie, Hôpital Pitié-Salpêtrière, Paris, France
| | - F Ziegler
- Service de Neurologie, Centre Hospitalier Intercommunale de la Haute Saône, Vesoul, France
| | - L Magy
- Centre de Référence Neuropathies Périphérique Rares, CHU de Limoges - Hôpital Dupuytren, Limoges, France
| | - E Fournier
- Département de Neurophysiologie Clinique, Hôpital Pitié-Salpêtrière, Paris, France
| | - O Dubourg
- Centre de Référence des Maladies Neuromusculaires Paris Est, Institut de Myologie, Hôpital Pitié-Salpêtrière, Paris, France
| | - P Bouche
- Département de Neurophysiologie Clinique, Hôpital Pitié-Salpêtrière, Paris, France
| | - T Maisonobe
- Département de Neurophysiologie Clinique, Hôpital Pitié-Salpêtrière, Paris, France
| | - A Lacour
- Clinique Neurologique, Centre Hospitalier Universitaire de Lille, Lille, France
| | - A Moerman
- Département de Génétique Médicale, Hôpital Jeanne de Flandres, Centre Hospitalier Universitaire de Lille, Lille, France
| | - P Latour
- Service de Neurobiologie, Centre de Biologie et Pathologie Est, Centre Hospitalier Universitaire de Lyon HCL, GH Est, Lyon, France
| | - T Stojkovic
- Centre de Référence des Maladies Neuromusculaires Paris Est, Institut de Myologie, Hôpital Pitié-Salpêtrière, Paris, France
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Gonorazky HD, Amburgey K, Yoon G, Vajsar J, Widjaja E, Dowling JJ. Subacute demyelinating peripheral neuropathy as a novel presentation of late infantile metachromatic leukodystrophy. Muscle Nerve 2017; 56:E41-E44. [PMID: 28667691 DOI: 10.1002/mus.25737] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 06/13/2017] [Accepted: 06/25/2017] [Indexed: 01/11/2023]
Affiliation(s)
- Hernan D Gonorazky
- Division of Neurology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Kimberly Amburgey
- Division of Neurology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Grace Yoon
- Division of Genetics, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Jiri Vajsar
- Division of Neurology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Elysa Widjaja
- Division of Radiology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - James J Dowling
- Division of Neurology, Hospital for Sick Children, Toronto, Ontario, Canada
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7
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Tomaselli PJ, Rossor AM, Horga A, Jaunmuktane Z, Carr A, Saveri P, Piscosquito G, Pareyson D, Laura M, Blake JC, Poh R, Polke J, Houlden H, Reilly MM. Mutations in noncoding regions of GJB1 are a major cause of X-linked CMT. Neurology 2017; 88:1445-1453. [PMID: 28283593 PMCID: PMC5386440 DOI: 10.1212/wnl.0000000000003819] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Accepted: 01/18/2017] [Indexed: 01/03/2023] Open
Abstract
OBJECTIVE To determine the prevalence and clinical and genetic characteristics of patients with X-linked Charcot-Marie-Tooth disease (CMT) due to mutations in noncoding regions of the gap junction β-1 gene (GJB1). METHODS Mutations were identified by bidirectional Sanger sequence analysis of the 595 bases of the upstream promoter region, and 25 bases of the 3' untranslated region (UTR) sequence in patients in whom mutations in the coding region had been excluded. Clinical and neurophysiologic data were retrospectively collected. RESULTS Five mutations were detected in 25 individuals from 10 kindreds representing 11.4% of all cases of CMTX1 diagnosed in our neurogenetics laboratory between 1996 and 2016. Four pathogenic mutations, c.-17G>A, c.-17+1G>T, c.-103C>T, and c.-146-90_146-89insT were detected in the 5'UTR. A novel mutation, c.*15C>T, was detected in the 3' UTR of GJB1 in 2 unrelated families with CMTX1 and is the first pathogenic mutation in the 3'UTR of any myelin-associated CMT gene. Mutations segregated with the phenotype, were at sites predicted to be pathogenic, and were not present in the normal population. CONCLUSIONS Mutations in noncoding DNA are a major cause of CMTX1 and highlight the importance of mutations in noncoding DNA in human disease. Next-generation sequencing platforms for use in inherited neuropathy should therefore include coverage of these regions.
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Affiliation(s)
- Pedro J Tomaselli
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - Alexander M Rossor
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - Alejandro Horga
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - Zane Jaunmuktane
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - Aisling Carr
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - Paola Saveri
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - Giuseppe Piscosquito
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - Davide Pareyson
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - Matilde Laura
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - Julian C Blake
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - Roy Poh
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - James Polke
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - Henry Houlden
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK
| | - Mary M Reilly
- From the MRC Centre for Neuromuscular Diseases (P.J.T., A.M.R., A.H., A.C., M.L., M.M.R.), Department of Neuropathology (Z.J.), and Department of Neurogenetics (R.P., J.P., H.H.), National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, Queen Square, London, UK; Clinic of Central and Peripheral Degenerative Neuropathies Unit (P.S., G.P., D.P.), Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy; Department of Clinical Neurophysiology (J.C.B.), Norfolk and Norwich University Hospital, Norfolk, UK.
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Intermediate Charcot–Marie–Tooth disease: an electrophysiological reappraisal and systematic review. J Neurol 2017; 264:1655-1677. [DOI: 10.1007/s00415-017-8474-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 03/23/2017] [Accepted: 03/24/2017] [Indexed: 01/13/2023]
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9
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Huang D, He X, Zou J, Guo P, Jiang S, Lv N, Alekseyev Y, Luo L, Luo Z. Negative regulation of Bmi-1 by AMPK and implication in cancer progression. Oncotarget 2017; 7:6188-200. [PMID: 26717043 PMCID: PMC4868749 DOI: 10.18632/oncotarget.6748] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 11/15/2015] [Indexed: 12/31/2022] Open
Abstract
Bmi-1 is a transcriptional regulator that promotes tumor cell self-renewal and epithelial to mesenchymal transition and its upregulation is associated with tumor progression, AMPK is an intracellular fuel-sensing enzyme and plays important roles in tumor cell growth and progression. Thus, the present study aims to examine the regulation of Bmi-1 by AMPK. First, our data revealed that, as compared to adjacent normal tissue, Bmi-1 was highly expressed in gastric cancer, whereas phosphorylation of AMPK (p-AMPK) was reduced. Similar findings were observed in lung adenocarcinomas and appeared that the expression of Bmi-1 was correlated with pathological grades of the cancer, where opposite changes were found in p-AMPK. Second, Metformin, a pharmacological AMPK activator and anti-diabetic drug, or ectopic expression of LKB1, diminished expression of Bmi-1 in cancer cells, an event that was reversed by silencing LKB1. Third, knockdown of LITAF, previously identified as a downstream target of AMPK, upregulated Bmi-1, associated with increased cell viability, colony formation, and migration of cancer cells in vitro. Fourth, metformin increased the abundance of miR-15a, miR-128, miR-192, and miR-194, which was prevented by knockdown of LITAF. Accordingly, transfection of these individual miRNAs downregulated Bmi-1. Altogether, our data for the first time suggest a regulatory axis in cancer cells: AMPK upregulates LITAF, which in turn increases miRNAs, leading to attenuation of Bmi-1 expression.
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Affiliation(s)
- Deqiang Huang
- Research Institute of Digestive Diseases, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Xiaoling He
- Graduate Program, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, P.R. China.,Institute of Basic Medical Sciences, Nanchang University, Nanchang, Jiangxi, P.R. China
| | - Junrong Zou
- Graduate Program, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, P.R. China.,Institute of Basic Medical Sciences, Nanchang University, Nanchang, Jiangxi, P.R. China
| | - Pei Guo
- Graduate Program, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, P.R. China.,Institute of Basic Medical Sciences, Nanchang University, Nanchang, Jiangxi, P.R. China
| | - Shanshan Jiang
- Graduate Program, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, P.R. China.,Institute of Basic Medical Sciences, Nanchang University, Nanchang, Jiangxi, P.R. China
| | - Nonghua Lv
- Research Institute of Digestive Diseases, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Yuriy Alekseyev
- Departments of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Lingyu Luo
- Research Institute of Digestive Diseases, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Zhijun Luo
- Institute of Basic Medical Sciences, Nanchang University, Nanchang, Jiangxi, P.R. China.,Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
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10
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Wang Y, Yin F. A Review of X-linked Charcot-Marie-Tooth Disease. J Child Neurol 2016; 31:761-72. [PMID: 26385972 DOI: 10.1177/0883073815604227] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 08/06/2015] [Indexed: 01/25/2023]
Abstract
X-linked Charcot-Marie-Tooth disease (CMTX) is the second common genetic variant of CMT. CMTX type 1 causes 90% of CMTX. The most important clinical features of CMTX are similar with other types of CMT; however, a few patients get the central nervous system involved with or without white matter lesions; males are more severely and earlier affected than females. In this review, the authors focus on the origin and classification of CMTX, the central nervous system manifestations of CMTX1, the possible mechanism by which GJB1 mutations cause CMT1X, and the emerging therapeutic strategies for CMTX. Moreover, several cases are presented to illustrate the central nervous system manifestations.
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Affiliation(s)
- Ying Wang
- Department of Pediatrics, Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Fei Yin
- Department of Pediatrics, Xiangya Hospital of Central South University, Changsha, Hunan, China Hunan Intellectual and Developmental Disabilities Research Center, Hunan, China
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11
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Abrams CK, Freidin M. GJB1-associated X-linked Charcot-Marie-Tooth disease, a disorder affecting the central and peripheral nervous systems. Cell Tissue Res 2015; 360:659-73. [PMID: 25370202 DOI: 10.1007/s00441-014-2014-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 09/22/2014] [Indexed: 11/24/2022]
Abstract
Charcot-Marie-Tooth disease (CMT) is a group of inherited diseases characterized by exclusive or predominant involvement of the peripheral nervous system. Mutations in GJB1, the gene encoding Connexin 32 (Cx32), a gap-junction channel forming protein, cause the most common X-linked form of CMT, CMT1X. Cx32 is expressed in Schwann cells and oligodendrocytes, the myelinating glia of the peripheral and central nervous systems, respectively. Thus, patients with CMT1X have both central and peripheral nervous system manifestations. Study of the genetics of CMT1X and the phenotypes of patients with this disorder suggest that the peripheral manifestations of CMT1X are likely to be due to loss of function, while in the CNS gain of function may contribute. Mice with targeted ablation of Gjb1 develop a peripheral neuropathy similar to that seen in patients with CMT1X, supporting loss of function as a mechanism for the peripheral manifestations of this disorder. Possible roles for Cx32 include the establishment of a reflexive gap junction pathway in the peripheral and central nervous system and of a panglial syncitium in the central nervous system.
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Affiliation(s)
- Charles K Abrams
- Departments of Neurology and Physiology & Pharmacology, State University of New York, Brooklyn, NY, 11203, USA,
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12
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Tsai PC, Chen CH, Liu AB, Chen YC, Soong BW, Lin KP, Yet SF, Lee YC. Mutational analysis of the 5' non-coding region of GJB1 in a Taiwanese cohort with Charcot-Marie-Tooth neuropathy. J Neurol Sci 2013; 332:51-5. [PMID: 23827825 DOI: 10.1016/j.jns.2013.06.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Accepted: 06/12/2013] [Indexed: 11/20/2022]
Abstract
Mutations in the 5' non-coding region of GJB1 are rarely reported in patients with Charcot-Marie-Tooth disease (CMT). We therefore aimed to assess the frequency and identities of the GJB1 5' non-coding region mutations in a cohort of CMT. We analyzed the 5' non-coding region of GJB1 (including the promoter P2 and exon 1b) in 91 unrelated CMT patients without an identified genetic cause. Two mutations, c.-529T>C, and c.-459C>T, were identified in one patient each. One polymorphism, c.-713G>A, was also identified in 53 patients and 73 of the 100 control subjects. The luciferase reporter assays showed that c.-459C>T significantly reduced the luciferase expression with or without SOX10 activation, whereas c.-529T>C impaired the expression only with SOX10 co-expression. c.-713G>A had no apparent functional effect. Mutations in the 5' non-coding region of GJB1 account for 0.8% (2 of 251) of CMT and 2.2% (2 of 91) of genetically unassigned CMT in a Taiwanese cohort. As previously demonstrated, c.-459C>T and c.-529T>C may cause CMT through compromising GJB1 expression whereas c.-713G>A is a benign variant. This study highlights the pathogenic role of the GJB1 5' non-coding region mutations in CMT, and suggests that their identification should be considered for CMT patients without commonly observed mutations.
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Affiliation(s)
- Pei-Chien Tsai
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan
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13
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Kleopa KA, Abrams CK, Scherer SS. How do mutations in GJB1 cause X-linked Charcot-Marie-Tooth disease? Brain Res 2012; 1487:198-205. [PMID: 22771394 PMCID: PMC3488165 DOI: 10.1016/j.brainres.2012.03.068] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 03/24/2012] [Indexed: 11/26/2022]
Abstract
The X-linked form of Charcot-Marie-Tooth disease (CMT1X) is the second most common form of hereditary motor and sensory neuropathy. The clinical phenotype is characterized by progressive weakness, atrophy, and sensory abnormalities that are most pronounced in the distal extremities. Some patients have CNS manifestations. Affected males have moderate to severe symptoms, whereas heterozygous females are usually less affected. Neurophysiology shows intermediate slowing of conduction and length-dependent axonal loss. Nerve biopsies show more prominent axonal degeneration than de/remyelination. Mutations in GJB1, the gene that encodes the gap junction (GJ) protein connexin32 (Cx32) cause CMT1X; more than 400 different mutations have been described. Many Cx32 mutants fail to form functional GJs, or form GJs with abnormal biophysical properties. Schwann cells and oligodendrocytes express Cx32, and the GJs formed by Cx32 play an important role in the homeostasis of myelinated axons. Animal models of CMT1X demonstrate that loss of Cx32 in myelinating Schwann cells causes a demyelinating neuropathy. Effective therapies remain to be developed. This article is part of a Special Issue entitled Electrical Synapses.
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Affiliation(s)
- Kleopas A Kleopa
- Neurology Clinics and Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
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14
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Abstract
BACKGROUND Charcot-Marie-Tooth disease (CMT) is the most common inherited disorder of the peripheral nervous system. The frequency of different CMT genotypes has been estimated in clinic populations, but prevalence data from the general population is lacking. Point mutations in the mitofusin 2 (MFN2) gene has been identified exclusively in Charcot-Marie-Tooth disease type 2 (CMT2), and in a single family with intermediate CMT. MFN2 point mutations are probably the most common cause of CMT2. The CMT phenotype caused by mutation in the myelin protein zero (MPZ) gene varies considerably, from early onset and severe forms to late onset and milder forms. The mechanism is not well understood. The myelin protein zero (P(0) ) mediates adhesion in the spiral wraps of the Schwann cell's myelin sheath. X-linked Charcot-Marie Tooth disease (CMTX) is caused by mutations in the connexin32 (cx32) gene that encodes a polypeptide which is arranged in hexameric array and form gap junctions. AIMS Estimate prevalence of CMT. Estimate frequency of Peripheral Myelin Protein 22 (PMP22) duplication and point mutations, insertions and deletions in Cx32, Early growth response 2 (EGR2), MFN2, MPZ, PMP22 and Small integral membrane protein of lysosome/late endosome (SIMPLE) genes. Description of novel mutations in Cx32, MFN2 and MPZ. Description of de novo mutations in MFN2. MATERIAL AND METHODS Our population based genetic epidemiological survey included persons with CMT residing in eastern Akershus County, Norway. The participants were interviewed and examined by one geneticist/neurologist, and classified clinically, neurophysiologically and genetically. Two-hundred and thirty-two consecutive unselected and unrelated CMT families with available DNA from all regions in Norway were included in the MFN2 study. We screened for point mutations in the MFN2 gene. We describe four novel mutations, two in the connexin32 gene and two in the MPZ gene. RESULTS A total of 245 affected from 116 CMT families from the general population of eastern Akershus county were included in the genetic epidemiological survey. In the general population 1 per 1214 persons (95% CI 1062-1366) has CMT. Charcot-Marie-Tooth disease type 1 (CMT1), CMT2 and intermediate CMT were found in 48.2%, 49.4% and 2.4% of the families, respectively. A mutation in the investigated genes was found in 27.2% of the CMT families and in 28.6% of the affected. The prevalence of the PMP22 duplication and mutations in the Cx32, MPZ and MFN2 genes was found in 13.6%, 6.2%, 1.2%, 6.2% of the families, and in 19.6%, 4.8%, 1.1%, 3.2% of the affected, respectively. None of the families had point mutations, insertions or deletions in the EGR2, PMP22 or SIMPLE genes. Four known and three novel mitofusin 2 (MFN2) point mutations in 8 unrelated Norwegian CMT families were identified. The novel point mutations were not found in 100 healthy controls. This corresponds to 3.4% (8/232) of CMT families having point mutations in MFN2. The phenotypes were compatible with CMT1 in two families, CMT2 in four families, intermediate CMT in one family and distal hereditary motor neuronopathy (dHMN) in one family. A point mutation in the MFN2 gene was found in 2.3% of CMT1, 5.5% of CMT2, 12.5% of intermediate CMT and 6.7% of dHMN families. Two novel missense mutations in the MPZ gene were identified. Family 1 had a c.368G>A (Gly123Asp) transition while family 2 and 3 had a c.103G>A (Asp35Asn) transition. The affected in family 1 had early onset and severe symptoms compatible with Dejerine-Sottas syndrome (DSS), while affected in family 2 and 3 had late onset, milder symptoms and axonal neuropathy compatible with CMT2. Two novel connexin32 mutations that cause early onset X-linked CMT were identified. Family 1 had a deletion c.225delG (R75fsX83) which causes a frameshift and premature stop codon at position 247 while family 2 had a c.536G>A (Cys179Tyr) transition which causes a change of the highly conserved cysteine residue, i.e. disruption of at least one of three disulfide bridges. The mean age at onset was in the first decade and the nerve conduction velocities were in the intermediate range. DISCUSSION Charcot-Marie-Tooth disease is the most common inherited neuropathy. At present 47 hereditary neuropathy genes are known, and an examination of all known genes would probably only identify mutations in approximately 50% of those with CMT. Thus, it is likely that at least 30-50 CMT genes are yet to be identified. The identified known and novel point mutations in the MFN2 gene expand the clinical spectrum from CMT2 and intermediate CMT to also include possibly CMT1 and the dHMN phenotypes. Thus, genetic analyses of the MFN2 gene should not be restricted to persons with CMT2. The phenotypic variation caused by different missense mutations in the MPZ gene is likely caused by different conformational changes of the MPZ protein which affects the functional tetramers. Severe changes of the MPZ protein cause dysfunctional tetramers and predominantly uncompacted myelin, i.e. the severe phenotypes congenital hypomyelinating neuropathy and DSS, while milder changes cause the phenotypes CMT1 and CMT2. The two novel mutations in the connexin32 gene are more severe than the majority of previously described mutations possibly due to the severe structural change of the gap junction they encode. CONCLUSION Charcot-Marie-Tooth disease is the most common inherited disorder of the peripheral nervous system with an estimated prevalence of 1 in 1214. CMT1 and CMT2 are equally frequent in the general population. The prevalence of PMP22 duplication and of mutations in Cx32, MPZ and MFN2 is 19.6%, 4.8%, 1.1% and 3.2%, respectively. The ratio of probable de novo mutations in CMT families was estimated to be 22.7%. Genotype- phenotype correlations for seven novel mutations in the genes Cx32 (2), MFN2 (3) and MPZ (2) are described. Two novel phenotypes were ascribed to the MFN2 gene, however further studies are needed to confirm that MFN2 mutations can cause CMT1 and dHMN.
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Affiliation(s)
- G J Braathen
- Head and Neck Research Group, Research Centre, Akershus University Hospital, Lørenskog, Norway.
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15
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Murphy SM, Polke J, Manji H, Blake J, Reiniger L, Sweeney M, Houlden H, Brandner S, Reilly MM. A novel mutation in the nerve-specific 5'UTR of the GJB1 gene causes X-linked Charcot-Marie-Tooth disease. J Peripher Nerv Syst 2011; 16:65-70. [PMID: 21504505 DOI: 10.1111/j.1529-8027.2011.00321.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
X-linked Charcot-Marie-Tooth disease (CMT1X) is the second most common cause of CMT, and is usually caused by mutations in the gap junction protein beta 1 (GJB1) gene which codes for connexin 32 (CX32). CX32 has three tissue-specific promoters, P1 which is specific for liver and pancreas, P1a specific for liver, oocytes and embryonic stem cells, and P2 which is nerve-specific. Over 300 mutations have been described in GJB1, spread throughout the coding region. We describe two families with X-linked inheritance and a phenotype consistent with CMT1X who did not have mutations in the GJB1 coding region. The non-coding region of GJB1 was sequenced and an upstream exon-splicing variant found at approximately - 373G>A which segregated with the disease in both families and was not present in controls. This substitution is located at the last base of the nerve-specific 5'UTR and thus may disrupt splicing of the nerve-specific transcript. Online consensus splice-site programs predict a reduced score for the mutant sequence vs. the normal sequence. It is likely that other mutations within the GJB1 non-coding regions account for the CMT1X families who do not have coding region mutations.
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Affiliation(s)
- Sinéad M Murphy
- MRC Centre for Neuromuscular Diseases, The National Hospital for Neurology and Neurosurgery, London, UK.
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Zhou J, Yang Z, Tsuji T, Gong J, Xie J, Chen C, Li W, Amar S, Luo Z. LITAF and TNFSF15, two downstream targets of AMPK, exert inhibitory effects on tumor growth. Oncogene 2011; 30:1892-900. [PMID: 21217782 PMCID: PMC3431012 DOI: 10.1038/onc.2010.575] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF) α factor (LITAF) is a multiple functional molecule whose sequence is identical to the small integral membrane protein of the lysosome/late endosome. LITAF was initially identified as a transcription factor that activates transcription of proinflammatory cytokine in macrophages in response to LPS. Mutations of the LITAF gene are associated with a genetic disease, called Charcot-Marie-Tooth syndrome. Recently, we have reported that mRNA levels of LITAF and TNF superfamily member 15 (TNFSF15) are upregulated by 5' adenosine monophosphate (AMP)-activated protein kinase (AMPK). The present study further assesses their biological functions. Thus, we show that 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR), a pharmacological activator of AMPK, increases the abundance of LITAF and TNFSF15 in LNCaP and C4-2 prostate cancer cells, which is abrogated by small hairpin RNA (shRNA) or the dominant-negative mutant of AMPK α1 subunit. Our data further demonstrate that AMPK activation upregulates the transcription of LITAF. Intriguingly, silencing LITAF by shRNA enhances proliferation, anchorage-independent growth of these cancer cells and tumor growth in the xenograft model. In addition, our study reveals that LITAF mediates the effect of AMPK by binding to a specific sequence in the promoter region. Furthermore, we show that TNFSF15 remarkably inhibits the growth of prostate cancer cells and bovine aortic endothelial cells in vitro, with a more potent effect toward the latter. In conjuncture, intratumoral injection of TNFSF15 significantly reduces the size of tumors and number of blood vessels and induces changes that are characteristic of tumor cell differentiation. Therefore, our studies for the first time establish the regulatory axis of AMPK-LITAF-TNFSF15 and also suggest that LITAF may function as a tumor suppressor.
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Affiliation(s)
- J Zhou
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
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17
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Abstract
The past 15 years have witnessed the identification of more than 25 genes responsible for inherited neuropathies in humans, many associated with primary alterations of the myelin sheath. A remarkable body of work in patients, as well as animal and cellular models, has defined the clinical and molecular genetics of these illnesses and shed light on how mutations in associated genes produce the heterogeneity of dysmyelinating and demyelinating phenotypes. Here, we review selected recent developments from work on the molecular mechanisms of these disorders and their implications for treatment strategies.
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Affiliation(s)
- Steven S Scherer
- The University of Pennsylvania Medical School, Philadelphia, Pennsylvania
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18
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Kochański A. How to assess the pathogenicity of mutations in Charcot-Marie-Tooth disease and other diseases? J Appl Genet 2006; 47:255-60. [PMID: 16877806 DOI: 10.1007/bf03194633] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Knowledge whether a certain DNA variant is a pathogenic mutation or a harmless polymorphism is a critical issue in medical genetics, in which results of a molecular analysis may serve as a basis for diagnosis and genetic counseling. Due to its genetic heterogeneity expressed at the levels of loci, genes and mutations, Charcot-Marie-Tooth (CMT) disease can serve as a model group of clinically homogenous diseases for studying the pathogenicity of mutations. Close to a 17p11.2-p12 duplication occurring in 70% of patients with the demyelinating form of CMT disease, numerous mutations have been identified in poorly characterized genes coding for proteins of an unknown function. Functional analyses, segregation analyses of large pedigrees, and inclusion of large control groups are required to assess the potential pathogenicity of CMT mutations. Hence, the pathogenicity of numerous CMT mutations remains unclear. Some variants detected in the CMT genes and originally described as pathogenic mutations have been shown to have a polymorphic character. In contrast, polymorphisms initially considered harmless were later reclassified as pathogenic mutations. However, the process of assessing the pathogenicity of mutations, as presented in this study for CMT disorders, is a more general issue concerning all disorders with a genetic background. Since the number of DNA variants is still growing, in the near future geneticists will increasingly have to cope with the problem of pathogenicity of identified genetic variants.
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Affiliation(s)
- Andrzej Kochański
- Neuromuscular Unit, Mossakowski Medical Research Center, Pawinskiego 5, 02-106 Warszawa, Poland.
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Latour P, Gonnaud PM, Ollagnon E, Chan V, Perelman S, Stojkovic T, Stoll C, Vial C, Ziegler F, Vandenberghe A, Maire I. SIMPLE mutation analysis in dominant demyelinating Charcot-Marie-Tooth disease: three novel mutations. J Peripher Nerv Syst 2006; 11:148-55. [PMID: 16787513 DOI: 10.1111/j.1085-9489.2006.00080.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Charcot-Marie-Tooth disease type 1C (CMT1C) is caused by mutations in the small integral membrane protein of the lysosome/late endosome (SIMPLE). We analyzed the coding sequence of SIMPLE in DNA of 53 unrelated cases of dominant demyelinating CMT disease with no mutations in PMP22, GJB1, MPZ, EGR2, and NEFL genes. Four different missense mutations were observed in six families. The mutation Gly112Ser was found in two families confirming its frequent occurrence in SIMPLE mutations. Three novel mutations were also identified: Ala111Gly (two families), Pro135Ser, and Pro135Thr. Familial studies revealed that all carriers of mutations (n = 38), aged from 1 to 78 years, were symptomatic, notably children under 10 years (n = 8). Motor conduction velocities in the median nerve ranked from 16.4 to 32.8 m/s (n = 20). In our series of 968 unrelated dominant demyelinating CMT cases (1992-2005), the percentage of SIMPLE mutations was 0.6 (6/968).
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Affiliation(s)
- Philippe Latour
- Neurogénétique, Laboratoire de Biochimie Pédiatrique, Hôpital Debrousse, Lyon, France.
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