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Sivera R, Pelayo-Negro AL, Jericó I, Domínguez-González C, Horga A, Rodriguez De Rivera FJ, Gallardo E, Tembl JI, Bermejo-Guerrero L, Pagola Lorz MI, Azorín I, Cordoba M, Fenollar-Cortés MDM, Millet E, Vilchez JJ, Espinós C, Apellániz-Ruiz M, Sevilla T. Expanding the Clinical Spectrum of DRP2-Associated Charcot-Marie-Tooth Disease. Neurology 2024; 102:e209174. [PMID: 38513194 DOI: 10.1212/wnl.0000000000209174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 12/11/2023] [Indexed: 03/23/2024] Open
Abstract
BACKGROUND AND OBJECTIVES Germline truncating variants in the DRP2 gene (encoding dystrophin-related protein 2) cause the disruption of the periaxin-DRP2-dystroglycan complex and have been linked to Charcot-Marie-Tooth disease. However, the causality and the underlying phenotype of the genetic alterations are not clearly defined. METHODS This cross-sectional retrospective observational study includes 9 patients with Charcot-Marie-Tooth disease (CMT) with DRP2 germline variants evaluated at 6 centers throughout Spain. RESULTS We identified 7 Spanish families with 4 different DRP2 likely pathogenic germline variants. In agreement with an X-linked inheritance, men harboring hemizygous DRP2 variants presented with an intermediate form of CMT, whereas heterozygous women were asymptomatic. Symptom onset was variable (36.6 ± 16 years), with lower limb weakness and multimodal sensory loss producing a mild-to-moderate functional impairment. Nerve echography revealed an increase in the cross-sectional area of nerve roots and proximal nerves. Lower limb muscle magnetic resonance imaging confirmed the presence of a length-dependent fatty infiltration. Immunostaining in intradermal nerve fibers demonstrated the absence of DRP2 and electron microscopy revealed abnormal myelin thickness that was also detectable in the sural nerve sections. DISCUSSION Our findings support the causality of DRP2 pathogenic germline variants in CMT and further define the phenotype as a late-onset sensory and motor length-dependent neuropathy, with intermediate velocities and thickening of proximal nerve segments.
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Affiliation(s)
- Rafael Sivera
- From the Servicio de Neurología (R.S., J.I.T., T.S.) and Servicio de Neurofisiología (E.M.), Unidad de Enfermedades Neuromusculares, Hospital Universitari i Politècnic La Fe, Grupo de Investigación en enfermedades neuromusculares y ataxias, Instituto de Investigación Sanitaria La Fe, Valencia; CIBER de enfermedades raras (CIBERER) (R.S., C.D.-G., I.A., J.J.V., C.E., T.S.) and Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) (A.L.P.-N., E.G.), Instituto de Salud Carlos III, Madrid; Servicio de Neurología (A.L.P.-N.), Hospital Universitario Marqués de Valdecilla (IDIVAL), Santander; Departamento de Neurología (I.J., M.I.P.L.), Hospital Universitario de Navarra, Instituto de Investigación Sanitaria de Navarra-IdiSNA, Pamplona; Servicio de Neurología (C.D.-G., L.B.-G.), Unidad de Enfermedades Neuromusculares, Hospital Universitario 12 de Octubre, Grupo de Investigación en Enfermedades mitocondriales y neuromusculares, Instituto de Investigación imas12; Servicio de Neurología (A.H.) and Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Servicio de Neurología (F.J.R.D.R.), Instituto de Investigación Sanitaria del Hospital Universitario La Paz - IDIPAZ, Hospital Universitario La Paz, Universidad Autónoma de Madrid; Servicio de Radiodiagnóstico (E.G.), Hospital Universitario Marqués de Valdecilla, Santander; Grupo de Investigación en enfermedades neuromusculares y ataxias (I.A., J.J.V.), Instituto de Investigación Sanitaria La Fe, Valencia; Área de Neurología (M.C.), Health in code; Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Lab of Rare Neurodegenerative Diseases (C.E.), Centro de Investigación Príncipe Felipe (CIPF), Valencia; Unidad de Medicina Genómica (M.A.-R.), Instituto de Investigación Sanitaria de Navarra-IdiSNA, Universidad Pública de Navarra (UPNA), Navarrabiomed, Hospital Universitario de Navarra (HUN), Pamplona; and Departamento de Medicina (T.S.), Universitat de Valencia, Spain
| | - Ana L Pelayo-Negro
- From the Servicio de Neurología (R.S., J.I.T., T.S.) and Servicio de Neurofisiología (E.M.), Unidad de Enfermedades Neuromusculares, Hospital Universitari i Politècnic La Fe, Grupo de Investigación en enfermedades neuromusculares y ataxias, Instituto de Investigación Sanitaria La Fe, Valencia; CIBER de enfermedades raras (CIBERER) (R.S., C.D.-G., I.A., J.J.V., C.E., T.S.) and Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) (A.L.P.-N., E.G.), Instituto de Salud Carlos III, Madrid; Servicio de Neurología (A.L.P.-N.), Hospital Universitario Marqués de Valdecilla (IDIVAL), Santander; Departamento de Neurología (I.J., M.I.P.L.), Hospital Universitario de Navarra, Instituto de Investigación Sanitaria de Navarra-IdiSNA, Pamplona; Servicio de Neurología (C.D.-G., L.B.-G.), Unidad de Enfermedades Neuromusculares, Hospital Universitario 12 de Octubre, Grupo de Investigación en Enfermedades mitocondriales y neuromusculares, Instituto de Investigación imas12; Servicio de Neurología (A.H.) and Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Servicio de Neurología (F.J.R.D.R.), Instituto de Investigación Sanitaria del Hospital Universitario La Paz - IDIPAZ, Hospital Universitario La Paz, Universidad Autónoma de Madrid; Servicio de Radiodiagnóstico (E.G.), Hospital Universitario Marqués de Valdecilla, Santander; Grupo de Investigación en enfermedades neuromusculares y ataxias (I.A., J.J.V.), Instituto de Investigación Sanitaria La Fe, Valencia; Área de Neurología (M.C.), Health in code; Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Lab of Rare Neurodegenerative Diseases (C.E.), Centro de Investigación Príncipe Felipe (CIPF), Valencia; Unidad de Medicina Genómica (M.A.-R.), Instituto de Investigación Sanitaria de Navarra-IdiSNA, Universidad Pública de Navarra (UPNA), Navarrabiomed, Hospital Universitario de Navarra (HUN), Pamplona; and Departamento de Medicina (T.S.), Universitat de Valencia, Spain
| | - Ivonne Jericó
- From the Servicio de Neurología (R.S., J.I.T., T.S.) and Servicio de Neurofisiología (E.M.), Unidad de Enfermedades Neuromusculares, Hospital Universitari i Politècnic La Fe, Grupo de Investigación en enfermedades neuromusculares y ataxias, Instituto de Investigación Sanitaria La Fe, Valencia; CIBER de enfermedades raras (CIBERER) (R.S., C.D.-G., I.A., J.J.V., C.E., T.S.) and Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) (A.L.P.-N., E.G.), Instituto de Salud Carlos III, Madrid; Servicio de Neurología (A.L.P.-N.), Hospital Universitario Marqués de Valdecilla (IDIVAL), Santander; Departamento de Neurología (I.J., M.I.P.L.), Hospital Universitario de Navarra, Instituto de Investigación Sanitaria de Navarra-IdiSNA, Pamplona; Servicio de Neurología (C.D.-G., L.B.-G.), Unidad de Enfermedades Neuromusculares, Hospital Universitario 12 de Octubre, Grupo de Investigación en Enfermedades mitocondriales y neuromusculares, Instituto de Investigación imas12; Servicio de Neurología (A.H.) and Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Servicio de Neurología (F.J.R.D.R.), Instituto de Investigación Sanitaria del Hospital Universitario La Paz - IDIPAZ, Hospital Universitario La Paz, Universidad Autónoma de Madrid; Servicio de Radiodiagnóstico (E.G.), Hospital Universitario Marqués de Valdecilla, Santander; Grupo de Investigación en enfermedades neuromusculares y ataxias (I.A., J.J.V.), Instituto de Investigación Sanitaria La Fe, Valencia; Área de Neurología (M.C.), Health in code; Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Lab of Rare Neurodegenerative Diseases (C.E.), Centro de Investigación Príncipe Felipe (CIPF), Valencia; Unidad de Medicina Genómica (M.A.-R.), Instituto de Investigación Sanitaria de Navarra-IdiSNA, Universidad Pública de Navarra (UPNA), Navarrabiomed, Hospital Universitario de Navarra (HUN), Pamplona; and Departamento de Medicina (T.S.), Universitat de Valencia, Spain
| | - Cristina Domínguez-González
- From the Servicio de Neurología (R.S., J.I.T., T.S.) and Servicio de Neurofisiología (E.M.), Unidad de Enfermedades Neuromusculares, Hospital Universitari i Politècnic La Fe, Grupo de Investigación en enfermedades neuromusculares y ataxias, Instituto de Investigación Sanitaria La Fe, Valencia; CIBER de enfermedades raras (CIBERER) (R.S., C.D.-G., I.A., J.J.V., C.E., T.S.) and Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) (A.L.P.-N., E.G.), Instituto de Salud Carlos III, Madrid; Servicio de Neurología (A.L.P.-N.), Hospital Universitario Marqués de Valdecilla (IDIVAL), Santander; Departamento de Neurología (I.J., M.I.P.L.), Hospital Universitario de Navarra, Instituto de Investigación Sanitaria de Navarra-IdiSNA, Pamplona; Servicio de Neurología (C.D.-G., L.B.-G.), Unidad de Enfermedades Neuromusculares, Hospital Universitario 12 de Octubre, Grupo de Investigación en Enfermedades mitocondriales y neuromusculares, Instituto de Investigación imas12; Servicio de Neurología (A.H.) and Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Servicio de Neurología (F.J.R.D.R.), Instituto de Investigación Sanitaria del Hospital Universitario La Paz - IDIPAZ, Hospital Universitario La Paz, Universidad Autónoma de Madrid; Servicio de Radiodiagnóstico (E.G.), Hospital Universitario Marqués de Valdecilla, Santander; Grupo de Investigación en enfermedades neuromusculares y ataxias (I.A., J.J.V.), Instituto de Investigación Sanitaria La Fe, Valencia; Área de Neurología (M.C.), Health in code; Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Lab of Rare Neurodegenerative Diseases (C.E.), Centro de Investigación Príncipe Felipe (CIPF), Valencia; Unidad de Medicina Genómica (M.A.-R.), Instituto de Investigación Sanitaria de Navarra-IdiSNA, Universidad Pública de Navarra (UPNA), Navarrabiomed, Hospital Universitario de Navarra (HUN), Pamplona; and Departamento de Medicina (T.S.), Universitat de Valencia, Spain
| | - Alejandro Horga
- From the Servicio de Neurología (R.S., J.I.T., T.S.) and Servicio de Neurofisiología (E.M.), Unidad de Enfermedades Neuromusculares, Hospital Universitari i Politècnic La Fe, Grupo de Investigación en enfermedades neuromusculares y ataxias, Instituto de Investigación Sanitaria La Fe, Valencia; CIBER de enfermedades raras (CIBERER) (R.S., C.D.-G., I.A., J.J.V., C.E., T.S.) and Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) (A.L.P.-N., E.G.), Instituto de Salud Carlos III, Madrid; Servicio de Neurología (A.L.P.-N.), Hospital Universitario Marqués de Valdecilla (IDIVAL), Santander; Departamento de Neurología (I.J., M.I.P.L.), Hospital Universitario de Navarra, Instituto de Investigación Sanitaria de Navarra-IdiSNA, Pamplona; Servicio de Neurología (C.D.-G., L.B.-G.), Unidad de Enfermedades Neuromusculares, Hospital Universitario 12 de Octubre, Grupo de Investigación en Enfermedades mitocondriales y neuromusculares, Instituto de Investigación imas12; Servicio de Neurología (A.H.) and Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Servicio de Neurología (F.J.R.D.R.), Instituto de Investigación Sanitaria del Hospital Universitario La Paz - IDIPAZ, Hospital Universitario La Paz, Universidad Autónoma de Madrid; Servicio de Radiodiagnóstico (E.G.), Hospital Universitario Marqués de Valdecilla, Santander; Grupo de Investigación en enfermedades neuromusculares y ataxias (I.A., J.J.V.), Instituto de Investigación Sanitaria La Fe, Valencia; Área de Neurología (M.C.), Health in code; Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Lab of Rare Neurodegenerative Diseases (C.E.), Centro de Investigación Príncipe Felipe (CIPF), Valencia; Unidad de Medicina Genómica (M.A.-R.), Instituto de Investigación Sanitaria de Navarra-IdiSNA, Universidad Pública de Navarra (UPNA), Navarrabiomed, Hospital Universitario de Navarra (HUN), Pamplona; and Departamento de Medicina (T.S.), Universitat de Valencia, Spain
| | - Francisco J Rodriguez De Rivera
- From the Servicio de Neurología (R.S., J.I.T., T.S.) and Servicio de Neurofisiología (E.M.), Unidad de Enfermedades Neuromusculares, Hospital Universitari i Politècnic La Fe, Grupo de Investigación en enfermedades neuromusculares y ataxias, Instituto de Investigación Sanitaria La Fe, Valencia; CIBER de enfermedades raras (CIBERER) (R.S., C.D.-G., I.A., J.J.V., C.E., T.S.) and Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) (A.L.P.-N., E.G.), Instituto de Salud Carlos III, Madrid; Servicio de Neurología (A.L.P.-N.), Hospital Universitario Marqués de Valdecilla (IDIVAL), Santander; Departamento de Neurología (I.J., M.I.P.L.), Hospital Universitario de Navarra, Instituto de Investigación Sanitaria de Navarra-IdiSNA, Pamplona; Servicio de Neurología (C.D.-G., L.B.-G.), Unidad de Enfermedades Neuromusculares, Hospital Universitario 12 de Octubre, Grupo de Investigación en Enfermedades mitocondriales y neuromusculares, Instituto de Investigación imas12; Servicio de Neurología (A.H.) and Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Servicio de Neurología (F.J.R.D.R.), Instituto de Investigación Sanitaria del Hospital Universitario La Paz - IDIPAZ, Hospital Universitario La Paz, Universidad Autónoma de Madrid; Servicio de Radiodiagnóstico (E.G.), Hospital Universitario Marqués de Valdecilla, Santander; Grupo de Investigación en enfermedades neuromusculares y ataxias (I.A., J.J.V.), Instituto de Investigación Sanitaria La Fe, Valencia; Área de Neurología (M.C.), Health in code; Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Lab of Rare Neurodegenerative Diseases (C.E.), Centro de Investigación Príncipe Felipe (CIPF), Valencia; Unidad de Medicina Genómica (M.A.-R.), Instituto de Investigación Sanitaria de Navarra-IdiSNA, Universidad Pública de Navarra (UPNA), Navarrabiomed, Hospital Universitario de Navarra (HUN), Pamplona; and Departamento de Medicina (T.S.), Universitat de Valencia, Spain
| | - Elena Gallardo
- From the Servicio de Neurología (R.S., J.I.T., T.S.) and Servicio de Neurofisiología (E.M.), Unidad de Enfermedades Neuromusculares, Hospital Universitari i Politècnic La Fe, Grupo de Investigación en enfermedades neuromusculares y ataxias, Instituto de Investigación Sanitaria La Fe, Valencia; CIBER de enfermedades raras (CIBERER) (R.S., C.D.-G., I.A., J.J.V., C.E., T.S.) and Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) (A.L.P.-N., E.G.), Instituto de Salud Carlos III, Madrid; Servicio de Neurología (A.L.P.-N.), Hospital Universitario Marqués de Valdecilla (IDIVAL), Santander; Departamento de Neurología (I.J., M.I.P.L.), Hospital Universitario de Navarra, Instituto de Investigación Sanitaria de Navarra-IdiSNA, Pamplona; Servicio de Neurología (C.D.-G., L.B.-G.), Unidad de Enfermedades Neuromusculares, Hospital Universitario 12 de Octubre, Grupo de Investigación en Enfermedades mitocondriales y neuromusculares, Instituto de Investigación imas12; Servicio de Neurología (A.H.) and Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Servicio de Neurología (F.J.R.D.R.), Instituto de Investigación Sanitaria del Hospital Universitario La Paz - IDIPAZ, Hospital Universitario La Paz, Universidad Autónoma de Madrid; Servicio de Radiodiagnóstico (E.G.), Hospital Universitario Marqués de Valdecilla, Santander; Grupo de Investigación en enfermedades neuromusculares y ataxias (I.A., J.J.V.), Instituto de Investigación Sanitaria La Fe, Valencia; Área de Neurología (M.C.), Health in code; Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Lab of Rare Neurodegenerative Diseases (C.E.), Centro de Investigación Príncipe Felipe (CIPF), Valencia; Unidad de Medicina Genómica (M.A.-R.), Instituto de Investigación Sanitaria de Navarra-IdiSNA, Universidad Pública de Navarra (UPNA), Navarrabiomed, Hospital Universitario de Navarra (HUN), Pamplona; and Departamento de Medicina (T.S.), Universitat de Valencia, Spain
| | - Jose Ignacio Tembl
- From the Servicio de Neurología (R.S., J.I.T., T.S.) and Servicio de Neurofisiología (E.M.), Unidad de Enfermedades Neuromusculares, Hospital Universitari i Politècnic La Fe, Grupo de Investigación en enfermedades neuromusculares y ataxias, Instituto de Investigación Sanitaria La Fe, Valencia; CIBER de enfermedades raras (CIBERER) (R.S., C.D.-G., I.A., J.J.V., C.E., T.S.) and Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) (A.L.P.-N., E.G.), Instituto de Salud Carlos III, Madrid; Servicio de Neurología (A.L.P.-N.), Hospital Universitario Marqués de Valdecilla (IDIVAL), Santander; Departamento de Neurología (I.J., M.I.P.L.), Hospital Universitario de Navarra, Instituto de Investigación Sanitaria de Navarra-IdiSNA, Pamplona; Servicio de Neurología (C.D.-G., L.B.-G.), Unidad de Enfermedades Neuromusculares, Hospital Universitario 12 de Octubre, Grupo de Investigación en Enfermedades mitocondriales y neuromusculares, Instituto de Investigación imas12; Servicio de Neurología (A.H.) and Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Servicio de Neurología (F.J.R.D.R.), Instituto de Investigación Sanitaria del Hospital Universitario La Paz - IDIPAZ, Hospital Universitario La Paz, Universidad Autónoma de Madrid; Servicio de Radiodiagnóstico (E.G.), Hospital Universitario Marqués de Valdecilla, Santander; Grupo de Investigación en enfermedades neuromusculares y ataxias (I.A., J.J.V.), Instituto de Investigación Sanitaria La Fe, Valencia; Área de Neurología (M.C.), Health in code; Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Lab of Rare Neurodegenerative Diseases (C.E.), Centro de Investigación Príncipe Felipe (CIPF), Valencia; Unidad de Medicina Genómica (M.A.-R.), Instituto de Investigación Sanitaria de Navarra-IdiSNA, Universidad Pública de Navarra (UPNA), Navarrabiomed, Hospital Universitario de Navarra (HUN), Pamplona; and Departamento de Medicina (T.S.), Universitat de Valencia, Spain
| | - Laura Bermejo-Guerrero
- From the Servicio de Neurología (R.S., J.I.T., T.S.) and Servicio de Neurofisiología (E.M.), Unidad de Enfermedades Neuromusculares, Hospital Universitari i Politècnic La Fe, Grupo de Investigación en enfermedades neuromusculares y ataxias, Instituto de Investigación Sanitaria La Fe, Valencia; CIBER de enfermedades raras (CIBERER) (R.S., C.D.-G., I.A., J.J.V., C.E., T.S.) and Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) (A.L.P.-N., E.G.), Instituto de Salud Carlos III, Madrid; Servicio de Neurología (A.L.P.-N.), Hospital Universitario Marqués de Valdecilla (IDIVAL), Santander; Departamento de Neurología (I.J., M.I.P.L.), Hospital Universitario de Navarra, Instituto de Investigación Sanitaria de Navarra-IdiSNA, Pamplona; Servicio de Neurología (C.D.-G., L.B.-G.), Unidad de Enfermedades Neuromusculares, Hospital Universitario 12 de Octubre, Grupo de Investigación en Enfermedades mitocondriales y neuromusculares, Instituto de Investigación imas12; Servicio de Neurología (A.H.) and Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Servicio de Neurología (F.J.R.D.R.), Instituto de Investigación Sanitaria del Hospital Universitario La Paz - IDIPAZ, Hospital Universitario La Paz, Universidad Autónoma de Madrid; Servicio de Radiodiagnóstico (E.G.), Hospital Universitario Marqués de Valdecilla, Santander; Grupo de Investigación en enfermedades neuromusculares y ataxias (I.A., J.J.V.), Instituto de Investigación Sanitaria La Fe, Valencia; Área de Neurología (M.C.), Health in code; Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Lab of Rare Neurodegenerative Diseases (C.E.), Centro de Investigación Príncipe Felipe (CIPF), Valencia; Unidad de Medicina Genómica (M.A.-R.), Instituto de Investigación Sanitaria de Navarra-IdiSNA, Universidad Pública de Navarra (UPNA), Navarrabiomed, Hospital Universitario de Navarra (HUN), Pamplona; and Departamento de Medicina (T.S.), Universitat de Valencia, Spain
| | - Maria Inmaculada Pagola Lorz
- From the Servicio de Neurología (R.S., J.I.T., T.S.) and Servicio de Neurofisiología (E.M.), Unidad de Enfermedades Neuromusculares, Hospital Universitari i Politècnic La Fe, Grupo de Investigación en enfermedades neuromusculares y ataxias, Instituto de Investigación Sanitaria La Fe, Valencia; CIBER de enfermedades raras (CIBERER) (R.S., C.D.-G., I.A., J.J.V., C.E., T.S.) and Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) (A.L.P.-N., E.G.), Instituto de Salud Carlos III, Madrid; Servicio de Neurología (A.L.P.-N.), Hospital Universitario Marqués de Valdecilla (IDIVAL), Santander; Departamento de Neurología (I.J., M.I.P.L.), Hospital Universitario de Navarra, Instituto de Investigación Sanitaria de Navarra-IdiSNA, Pamplona; Servicio de Neurología (C.D.-G., L.B.-G.), Unidad de Enfermedades Neuromusculares, Hospital Universitario 12 de Octubre, Grupo de Investigación en Enfermedades mitocondriales y neuromusculares, Instituto de Investigación imas12; Servicio de Neurología (A.H.) and Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Servicio de Neurología (F.J.R.D.R.), Instituto de Investigación Sanitaria del Hospital Universitario La Paz - IDIPAZ, Hospital Universitario La Paz, Universidad Autónoma de Madrid; Servicio de Radiodiagnóstico (E.G.), Hospital Universitario Marqués de Valdecilla, Santander; Grupo de Investigación en enfermedades neuromusculares y ataxias (I.A., J.J.V.), Instituto de Investigación Sanitaria La Fe, Valencia; Área de Neurología (M.C.), Health in code; Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Lab of Rare Neurodegenerative Diseases (C.E.), Centro de Investigación Príncipe Felipe (CIPF), Valencia; Unidad de Medicina Genómica (M.A.-R.), Instituto de Investigación Sanitaria de Navarra-IdiSNA, Universidad Pública de Navarra (UPNA), Navarrabiomed, Hospital Universitario de Navarra (HUN), Pamplona; and Departamento de Medicina (T.S.), Universitat de Valencia, Spain
| | - Inmaculada Azorín
- From the Servicio de Neurología (R.S., J.I.T., T.S.) and Servicio de Neurofisiología (E.M.), Unidad de Enfermedades Neuromusculares, Hospital Universitari i Politècnic La Fe, Grupo de Investigación en enfermedades neuromusculares y ataxias, Instituto de Investigación Sanitaria La Fe, Valencia; CIBER de enfermedades raras (CIBERER) (R.S., C.D.-G., I.A., J.J.V., C.E., T.S.) and Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) (A.L.P.-N., E.G.), Instituto de Salud Carlos III, Madrid; Servicio de Neurología (A.L.P.-N.), Hospital Universitario Marqués de Valdecilla (IDIVAL), Santander; Departamento de Neurología (I.J., M.I.P.L.), Hospital Universitario de Navarra, Instituto de Investigación Sanitaria de Navarra-IdiSNA, Pamplona; Servicio de Neurología (C.D.-G., L.B.-G.), Unidad de Enfermedades Neuromusculares, Hospital Universitario 12 de Octubre, Grupo de Investigación en Enfermedades mitocondriales y neuromusculares, Instituto de Investigación imas12; Servicio de Neurología (A.H.) and Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Servicio de Neurología (F.J.R.D.R.), Instituto de Investigación Sanitaria del Hospital Universitario La Paz - IDIPAZ, Hospital Universitario La Paz, Universidad Autónoma de Madrid; Servicio de Radiodiagnóstico (E.G.), Hospital Universitario Marqués de Valdecilla, Santander; Grupo de Investigación en enfermedades neuromusculares y ataxias (I.A., J.J.V.), Instituto de Investigación Sanitaria La Fe, Valencia; Área de Neurología (M.C.), Health in code; Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Lab of Rare Neurodegenerative Diseases (C.E.), Centro de Investigación Príncipe Felipe (CIPF), Valencia; Unidad de Medicina Genómica (M.A.-R.), Instituto de Investigación Sanitaria de Navarra-IdiSNA, Universidad Pública de Navarra (UPNA), Navarrabiomed, Hospital Universitario de Navarra (HUN), Pamplona; and Departamento de Medicina (T.S.), Universitat de Valencia, Spain
| | - Marta Cordoba
- From the Servicio de Neurología (R.S., J.I.T., T.S.) and Servicio de Neurofisiología (E.M.), Unidad de Enfermedades Neuromusculares, Hospital Universitari i Politècnic La Fe, Grupo de Investigación en enfermedades neuromusculares y ataxias, Instituto de Investigación Sanitaria La Fe, Valencia; CIBER de enfermedades raras (CIBERER) (R.S., C.D.-G., I.A., J.J.V., C.E., T.S.) and Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) (A.L.P.-N., E.G.), Instituto de Salud Carlos III, Madrid; Servicio de Neurología (A.L.P.-N.), Hospital Universitario Marqués de Valdecilla (IDIVAL), Santander; Departamento de Neurología (I.J., M.I.P.L.), Hospital Universitario de Navarra, Instituto de Investigación Sanitaria de Navarra-IdiSNA, Pamplona; Servicio de Neurología (C.D.-G., L.B.-G.), Unidad de Enfermedades Neuromusculares, Hospital Universitario 12 de Octubre, Grupo de Investigación en Enfermedades mitocondriales y neuromusculares, Instituto de Investigación imas12; Servicio de Neurología (A.H.) and Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Servicio de Neurología (F.J.R.D.R.), Instituto de Investigación Sanitaria del Hospital Universitario La Paz - IDIPAZ, Hospital Universitario La Paz, Universidad Autónoma de Madrid; Servicio de Radiodiagnóstico (E.G.), Hospital Universitario Marqués de Valdecilla, Santander; Grupo de Investigación en enfermedades neuromusculares y ataxias (I.A., J.J.V.), Instituto de Investigación Sanitaria La Fe, Valencia; Área de Neurología (M.C.), Health in code; Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Lab of Rare Neurodegenerative Diseases (C.E.), Centro de Investigación Príncipe Felipe (CIPF), Valencia; Unidad de Medicina Genómica (M.A.-R.), Instituto de Investigación Sanitaria de Navarra-IdiSNA, Universidad Pública de Navarra (UPNA), Navarrabiomed, Hospital Universitario de Navarra (HUN), Pamplona; and Departamento de Medicina (T.S.), Universitat de Valencia, Spain
| | - María Del Mar Fenollar-Cortés
- From the Servicio de Neurología (R.S., J.I.T., T.S.) and Servicio de Neurofisiología (E.M.), Unidad de Enfermedades Neuromusculares, Hospital Universitari i Politècnic La Fe, Grupo de Investigación en enfermedades neuromusculares y ataxias, Instituto de Investigación Sanitaria La Fe, Valencia; CIBER de enfermedades raras (CIBERER) (R.S., C.D.-G., I.A., J.J.V., C.E., T.S.) and Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) (A.L.P.-N., E.G.), Instituto de Salud Carlos III, Madrid; Servicio de Neurología (A.L.P.-N.), Hospital Universitario Marqués de Valdecilla (IDIVAL), Santander; Departamento de Neurología (I.J., M.I.P.L.), Hospital Universitario de Navarra, Instituto de Investigación Sanitaria de Navarra-IdiSNA, Pamplona; Servicio de Neurología (C.D.-G., L.B.-G.), Unidad de Enfermedades Neuromusculares, Hospital Universitario 12 de Octubre, Grupo de Investigación en Enfermedades mitocondriales y neuromusculares, Instituto de Investigación imas12; Servicio de Neurología (A.H.) and Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Servicio de Neurología (F.J.R.D.R.), Instituto de Investigación Sanitaria del Hospital Universitario La Paz - IDIPAZ, Hospital Universitario La Paz, Universidad Autónoma de Madrid; Servicio de Radiodiagnóstico (E.G.), Hospital Universitario Marqués de Valdecilla, Santander; Grupo de Investigación en enfermedades neuromusculares y ataxias (I.A., J.J.V.), Instituto de Investigación Sanitaria La Fe, Valencia; Área de Neurología (M.C.), Health in code; Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Lab of Rare Neurodegenerative Diseases (C.E.), Centro de Investigación Príncipe Felipe (CIPF), Valencia; Unidad de Medicina Genómica (M.A.-R.), Instituto de Investigación Sanitaria de Navarra-IdiSNA, Universidad Pública de Navarra (UPNA), Navarrabiomed, Hospital Universitario de Navarra (HUN), Pamplona; and Departamento de Medicina (T.S.), Universitat de Valencia, Spain
| | - Elvira Millet
- From the Servicio de Neurología (R.S., J.I.T., T.S.) and Servicio de Neurofisiología (E.M.), Unidad de Enfermedades Neuromusculares, Hospital Universitari i Politècnic La Fe, Grupo de Investigación en enfermedades neuromusculares y ataxias, Instituto de Investigación Sanitaria La Fe, Valencia; CIBER de enfermedades raras (CIBERER) (R.S., C.D.-G., I.A., J.J.V., C.E., T.S.) and Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) (A.L.P.-N., E.G.), Instituto de Salud Carlos III, Madrid; Servicio de Neurología (A.L.P.-N.), Hospital Universitario Marqués de Valdecilla (IDIVAL), Santander; Departamento de Neurología (I.J., M.I.P.L.), Hospital Universitario de Navarra, Instituto de Investigación Sanitaria de Navarra-IdiSNA, Pamplona; Servicio de Neurología (C.D.-G., L.B.-G.), Unidad de Enfermedades Neuromusculares, Hospital Universitario 12 de Octubre, Grupo de Investigación en Enfermedades mitocondriales y neuromusculares, Instituto de Investigación imas12; Servicio de Neurología (A.H.) and Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Servicio de Neurología (F.J.R.D.R.), Instituto de Investigación Sanitaria del Hospital Universitario La Paz - IDIPAZ, Hospital Universitario La Paz, Universidad Autónoma de Madrid; Servicio de Radiodiagnóstico (E.G.), Hospital Universitario Marqués de Valdecilla, Santander; Grupo de Investigación en enfermedades neuromusculares y ataxias (I.A., J.J.V.), Instituto de Investigación Sanitaria La Fe, Valencia; Área de Neurología (M.C.), Health in code; Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Lab of Rare Neurodegenerative Diseases (C.E.), Centro de Investigación Príncipe Felipe (CIPF), Valencia; Unidad de Medicina Genómica (M.A.-R.), Instituto de Investigación Sanitaria de Navarra-IdiSNA, Universidad Pública de Navarra (UPNA), Navarrabiomed, Hospital Universitario de Navarra (HUN), Pamplona; and Departamento de Medicina (T.S.), Universitat de Valencia, Spain
| | - Juan J Vilchez
- From the Servicio de Neurología (R.S., J.I.T., T.S.) and Servicio de Neurofisiología (E.M.), Unidad de Enfermedades Neuromusculares, Hospital Universitari i Politècnic La Fe, Grupo de Investigación en enfermedades neuromusculares y ataxias, Instituto de Investigación Sanitaria La Fe, Valencia; CIBER de enfermedades raras (CIBERER) (R.S., C.D.-G., I.A., J.J.V., C.E., T.S.) and Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) (A.L.P.-N., E.G.), Instituto de Salud Carlos III, Madrid; Servicio de Neurología (A.L.P.-N.), Hospital Universitario Marqués de Valdecilla (IDIVAL), Santander; Departamento de Neurología (I.J., M.I.P.L.), Hospital Universitario de Navarra, Instituto de Investigación Sanitaria de Navarra-IdiSNA, Pamplona; Servicio de Neurología (C.D.-G., L.B.-G.), Unidad de Enfermedades Neuromusculares, Hospital Universitario 12 de Octubre, Grupo de Investigación en Enfermedades mitocondriales y neuromusculares, Instituto de Investigación imas12; Servicio de Neurología (A.H.) and Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Servicio de Neurología (F.J.R.D.R.), Instituto de Investigación Sanitaria del Hospital Universitario La Paz - IDIPAZ, Hospital Universitario La Paz, Universidad Autónoma de Madrid; Servicio de Radiodiagnóstico (E.G.), Hospital Universitario Marqués de Valdecilla, Santander; Grupo de Investigación en enfermedades neuromusculares y ataxias (I.A., J.J.V.), Instituto de Investigación Sanitaria La Fe, Valencia; Área de Neurología (M.C.), Health in code; Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Lab of Rare Neurodegenerative Diseases (C.E.), Centro de Investigación Príncipe Felipe (CIPF), Valencia; Unidad de Medicina Genómica (M.A.-R.), Instituto de Investigación Sanitaria de Navarra-IdiSNA, Universidad Pública de Navarra (UPNA), Navarrabiomed, Hospital Universitario de Navarra (HUN), Pamplona; and Departamento de Medicina (T.S.), Universitat de Valencia, Spain
| | - Carmen Espinós
- From the Servicio de Neurología (R.S., J.I.T., T.S.) and Servicio de Neurofisiología (E.M.), Unidad de Enfermedades Neuromusculares, Hospital Universitari i Politècnic La Fe, Grupo de Investigación en enfermedades neuromusculares y ataxias, Instituto de Investigación Sanitaria La Fe, Valencia; CIBER de enfermedades raras (CIBERER) (R.S., C.D.-G., I.A., J.J.V., C.E., T.S.) and Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) (A.L.P.-N., E.G.), Instituto de Salud Carlos III, Madrid; Servicio de Neurología (A.L.P.-N.), Hospital Universitario Marqués de Valdecilla (IDIVAL), Santander; Departamento de Neurología (I.J., M.I.P.L.), Hospital Universitario de Navarra, Instituto de Investigación Sanitaria de Navarra-IdiSNA, Pamplona; Servicio de Neurología (C.D.-G., L.B.-G.), Unidad de Enfermedades Neuromusculares, Hospital Universitario 12 de Octubre, Grupo de Investigación en Enfermedades mitocondriales y neuromusculares, Instituto de Investigación imas12; Servicio de Neurología (A.H.) and Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Servicio de Neurología (F.J.R.D.R.), Instituto de Investigación Sanitaria del Hospital Universitario La Paz - IDIPAZ, Hospital Universitario La Paz, Universidad Autónoma de Madrid; Servicio de Radiodiagnóstico (E.G.), Hospital Universitario Marqués de Valdecilla, Santander; Grupo de Investigación en enfermedades neuromusculares y ataxias (I.A., J.J.V.), Instituto de Investigación Sanitaria La Fe, Valencia; Área de Neurología (M.C.), Health in code; Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Lab of Rare Neurodegenerative Diseases (C.E.), Centro de Investigación Príncipe Felipe (CIPF), Valencia; Unidad de Medicina Genómica (M.A.-R.), Instituto de Investigación Sanitaria de Navarra-IdiSNA, Universidad Pública de Navarra (UPNA), Navarrabiomed, Hospital Universitario de Navarra (HUN), Pamplona; and Departamento de Medicina (T.S.), Universitat de Valencia, Spain
| | - María Apellániz-Ruiz
- From the Servicio de Neurología (R.S., J.I.T., T.S.) and Servicio de Neurofisiología (E.M.), Unidad de Enfermedades Neuromusculares, Hospital Universitari i Politècnic La Fe, Grupo de Investigación en enfermedades neuromusculares y ataxias, Instituto de Investigación Sanitaria La Fe, Valencia; CIBER de enfermedades raras (CIBERER) (R.S., C.D.-G., I.A., J.J.V., C.E., T.S.) and Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) (A.L.P.-N., E.G.), Instituto de Salud Carlos III, Madrid; Servicio de Neurología (A.L.P.-N.), Hospital Universitario Marqués de Valdecilla (IDIVAL), Santander; Departamento de Neurología (I.J., M.I.P.L.), Hospital Universitario de Navarra, Instituto de Investigación Sanitaria de Navarra-IdiSNA, Pamplona; Servicio de Neurología (C.D.-G., L.B.-G.), Unidad de Enfermedades Neuromusculares, Hospital Universitario 12 de Octubre, Grupo de Investigación en Enfermedades mitocondriales y neuromusculares, Instituto de Investigación imas12; Servicio de Neurología (A.H.) and Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Servicio de Neurología (F.J.R.D.R.), Instituto de Investigación Sanitaria del Hospital Universitario La Paz - IDIPAZ, Hospital Universitario La Paz, Universidad Autónoma de Madrid; Servicio de Radiodiagnóstico (E.G.), Hospital Universitario Marqués de Valdecilla, Santander; Grupo de Investigación en enfermedades neuromusculares y ataxias (I.A., J.J.V.), Instituto de Investigación Sanitaria La Fe, Valencia; Área de Neurología (M.C.), Health in code; Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Lab of Rare Neurodegenerative Diseases (C.E.), Centro de Investigación Príncipe Felipe (CIPF), Valencia; Unidad de Medicina Genómica (M.A.-R.), Instituto de Investigación Sanitaria de Navarra-IdiSNA, Universidad Pública de Navarra (UPNA), Navarrabiomed, Hospital Universitario de Navarra (HUN), Pamplona; and Departamento de Medicina (T.S.), Universitat de Valencia, Spain
| | - Teresa Sevilla
- From the Servicio de Neurología (R.S., J.I.T., T.S.) and Servicio de Neurofisiología (E.M.), Unidad de Enfermedades Neuromusculares, Hospital Universitari i Politècnic La Fe, Grupo de Investigación en enfermedades neuromusculares y ataxias, Instituto de Investigación Sanitaria La Fe, Valencia; CIBER de enfermedades raras (CIBERER) (R.S., C.D.-G., I.A., J.J.V., C.E., T.S.) and Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) (A.L.P.-N., E.G.), Instituto de Salud Carlos III, Madrid; Servicio de Neurología (A.L.P.-N.), Hospital Universitario Marqués de Valdecilla (IDIVAL), Santander; Departamento de Neurología (I.J., M.I.P.L.), Hospital Universitario de Navarra, Instituto de Investigación Sanitaria de Navarra-IdiSNA, Pamplona; Servicio de Neurología (C.D.-G., L.B.-G.), Unidad de Enfermedades Neuromusculares, Hospital Universitario 12 de Octubre, Grupo de Investigación en Enfermedades mitocondriales y neuromusculares, Instituto de Investigación imas12; Servicio de Neurología (A.H.) and Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Servicio de Neurología (F.J.R.D.R.), Instituto de Investigación Sanitaria del Hospital Universitario La Paz - IDIPAZ, Hospital Universitario La Paz, Universidad Autónoma de Madrid; Servicio de Radiodiagnóstico (E.G.), Hospital Universitario Marqués de Valdecilla, Santander; Grupo de Investigación en enfermedades neuromusculares y ataxias (I.A., J.J.V.), Instituto de Investigación Sanitaria La Fe, Valencia; Área de Neurología (M.C.), Health in code; Unidad de Genética Clínica (M.M.F.-C.), Servicio de Análisis Clínicos, Instituto de Medicina de Laboratorio, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos de Madrid-IdISSC; Lab of Rare Neurodegenerative Diseases (C.E.), Centro de Investigación Príncipe Felipe (CIPF), Valencia; Unidad de Medicina Genómica (M.A.-R.), Instituto de Investigación Sanitaria de Navarra-IdiSNA, Universidad Pública de Navarra (UPNA), Navarrabiomed, Hospital Universitario de Navarra (HUN), Pamplona; and Departamento de Medicina (T.S.), Universitat de Valencia, Spain
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Ferrara JM, Wiid M, Burke S. Contactin-Associated Protein-Like 2-Related Peripheral Nerve Hyperexcitability Associated With Charcot-Marie-Tooth Type 4F. Neurohospitalist 2023; 13:164-168. [PMID: 37064943 PMCID: PMC10091429 DOI: 10.1177/19418744221140182] [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: 02/17/2023] Open
Abstract
Contactin-associated protein-like 2 autoimmunity is an uncommon disorder resulting in peripheral nerve hyperexcitability or encephalitis. In a fifth of cases, onset may be provoked by thymoma, but other associations are largely unknown. We report a patient with anti-contactin-associated protein-like 2-related peripheral nerve hyperexcitability arising in the setting of Charcot-Marie-Tooth type 4F and discuss potential mechanisms underlying the association.
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Affiliation(s)
- Joseph M. Ferrara
- Division of Neurology, Department of
Internal Medicine, East Carolina University School of
Medicine, Greenville, NC, USA
- Department of Internal Medicine, Virginia Tech Carilion, Roanoke, VA, USA
| | - Michael Wiid
- Department of Internal Medicine, Virginia Tech Carilion, Roanoke, VA, USA
| | - Sean Burke
- Department of Internal Medicine, Virginia Tech Carilion, Roanoke, VA, USA
- Comprehensive Neurology Services, Frederick Health, Frederick, MD, USA
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CD200R1 Contributes to Successful Functional Reinnervation after a Sciatic Nerve Injury. Cells 2022; 11:cells11111786. [PMID: 35681481 PMCID: PMC9179995 DOI: 10.3390/cells11111786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 05/20/2022] [Accepted: 05/23/2022] [Indexed: 11/16/2022] Open
Abstract
Activating and inhibitory immune receptors play a critical role in regulating systemic and central nervous system (CNS) immune and inflammatory processes. The CD200R1 immunoreceptor induces a restraining signal modulating inflammation and phagocytosis in the CNS under different inflammatory conditions. However, it remains unknown whether CD200R1 has a role in modulating the inflammatory response after a peripheral nerve injury, an essential component of the successful regeneration. Expression of CD200R1 and its ligand CD200 was analyzed during homeostasis and after a sciatic nerve crush injury in C57Bl/6 mice. The role of CD200R1 in Wallerian Degeneration (WD) and nerve regeneration was studied using a specific antibody against CD200R1 injected into the nerve at the time of injury. We found an upregulation of CD200R1 mRNA after injury whereas CD200 was downregulated acutely after nerve injury. Blockade of CD200R1 significantly reduced the acute entrance of both neutrophils and monocytes from blood after nerve injury. When long term regeneration and functional recovery were evaluated, we found that blockade of CD200R1 had a significant effect impairing the spontaneous functional recovery. Taken together, these results show that CD200R1 has a role in mounting a successful acute inflammatory reaction after injury, and contributes to an effective functional recovery.
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Abstract
Myelin is a key evolutionary specialization and adaptation of vertebrates formed by the plasma membrane of glial cells, which insulate axons in the nervous system. Myelination not only allows rapid and efficient transmission of electric impulses in the axon by decreasing capacitance and increasing resistance but also influences axonal metabolism and the plasticity of neural circuits. In this review, we will focus on Schwann cells, the glial cells which form myelin in the peripheral nervous system. Here, we will describe the main extrinsic and intrinsic signals inducing Schwann cell differentiation and myelination and how myelin biogenesis is achieved. Finally, we will also discuss how the study of human disorders in which molecules and pathways relevant for myelination are altered has enormously contributed to the current knowledge on myelin biology.
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Affiliation(s)
- Alessandra Bolino
- Human Inherited Neuropathies Unit, Institute of Experimental Neurology INSPE, Division of Neuroscience, IRCCS Ospedale San Raffaele, Via Olgettina 60, 20132, Milan, Italy.
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5
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Malavasi EL, Ghosh A, Booth DG, Zagnoni M, Sherman DL, Brophy PJ. Dynamic early clusters of nodal proteins contribute to node of Ranvier assembly during myelination of peripheral neurons. eLife 2021; 10:68089. [PMID: 34240706 PMCID: PMC8289411 DOI: 10.7554/elife.68089] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 07/07/2021] [Indexed: 12/31/2022] Open
Abstract
Voltage-gated sodium channels cluster in macromolecular complexes at nodes of Ranvier to promote rapid nerve impulse conduction in vertebrate nerves. Node assembly in peripheral nerves is thought to be initiated at heminodes at the extremities of myelinating Schwann cells, and fusion of heminodes results in the establishment of nodes. Here we show that assembly of 'early clusters' of nodal proteins in the murine axonal membrane precedes heminode formation. The neurofascin (Nfasc) proteins are essential for node assembly, and the formation of early clusters also requires neuronal Nfasc. Early clusters are mobile and their proteins are dynamically recruited by lateral diffusion. They can undergo fusion not only with each other but also with heminodes, thus contributing to the development of nodes in peripheral axons. The formation of early clusters constitutes the earliest stage in peripheral node assembly and expands the repertoire of strategies that have evolved to establish these essential structures.
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Affiliation(s)
- Elise Lv Malavasi
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Aniket Ghosh
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Daniel G Booth
- Biodiscovery Institute, University of Nottingham, Nottingham, United Kingdom
| | - Michele Zagnoni
- Centre for Microsystems & Photonics, Dept. Electronic and Electrical Engineering, University of Strathclyde, Strathclyde, United Kingdom
| | - Diane L Sherman
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Peter J Brophy
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
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6
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Genetic mechanisms of peripheral nerve disease. Neurosci Lett 2020; 742:135357. [PMID: 33249104 DOI: 10.1016/j.neulet.2020.135357] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/24/2020] [Accepted: 09/02/2020] [Indexed: 12/17/2022]
Abstract
Peripheral neuropathies of genetic etiology are a very diverse group of disorders manifesting either as non-syndromic inherited neuropathies without significant manifestations outside the peripheral nervous system, or as part of a systemic or syndromic genetic disorder. The former and most frequent group is collectively known as Charcot-Marie-Tooth disease (CMT), with prevalence as high as 1:2,500 world-wide, and has proven to be genetically highly heterogeneous. More than 100 different genes have been identified so far to cause various CMT forms, following all possible inheritance patterns. CMT causative genes belong to several common functional pathways that are essential for the integrity of the peripheral nerve. Their discovery has provided insights into the normal biology of axons and myelinating cells, and has highlighted the molecular mechanisms including both loss of function and gain of function effects, leading to peripheral nerve degeneration. Demyelinating neuropathies result from dysfunction of genes primarily affecting myelinating Schwann cells, while axonal neuropathies are caused by genes affecting mostly neurons and their long axons. Furthermore, mutation in genes expressed outside the nervous system, as in the case of inherited amyloid neuropathies, may cause peripheral neuropathy resulting from accumulation of β-structured amyloid fibrils in peripheral nerves in addition to various organs. Increasing insights into the molecular-genetic mechanisms have revealed potential therapeutic targets. These will enable the development of novel therapeutics for genetic neuropathies that remain, in their majority, without effective treatment.
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7
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Muppirala AN, Limbach LE, Bradford EF, Petersen SC. Schwann cell development: From neural crest to myelin sheath. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2020; 10:e398. [PMID: 33145925 DOI: 10.1002/wdev.398] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 10/06/2020] [Accepted: 10/07/2020] [Indexed: 12/16/2022]
Abstract
Vertebrate nervous system function requires glial cells, including myelinating glia that insulate axons and provide trophic support that allows for efficient signal propagation by neurons. In vertebrate peripheral nervous systems, neural crest-derived glial cells known as Schwann cells (SCs) generate myelin by encompassing and iteratively wrapping membrane around single axon segments. SC gliogenesis and neurogenesis are intimately linked and governed by a complex molecular environment that shapes their developmental trajectory. Changes in this external milieu drive developing SCs through a series of distinct morphological and transcriptional stages from the neural crest to a variety of glial derivatives, including the myelinating sublineage. Cues originate from the extracellular matrix, adjacent axons, and the developing SC basal lamina to trigger intracellular signaling cascades and gene expression changes that specify stages and transitions in SC development. Here, we integrate the findings from in vitro neuron-glia co-culture experiments with in vivo studies investigating SC development, particularly in zebrafish and mouse, to highlight critical factors that specify SC fate. Ultimately, we connect classic biochemical and mutant studies with modern genetic and visualization tools that have elucidated the dynamics of SC development. This article is categorized under: Signaling Pathways > Cell Fate Signaling Nervous System Development > Vertebrates: Regional Development.
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Affiliation(s)
- Anoohya N Muppirala
- Program in Neuroscience, Harvard Medical School, Boston, Massachusetts, USA.,Department of Neuroscience, Kenyon College, Gambier, Ohio, USA
| | | | | | - Sarah C Petersen
- Department of Neuroscience, Kenyon College, Gambier, Ohio, USA.,Department of Biology, Kenyon College, Gambier, Ohio, USA
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8
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Myelination of peripheral nerves is controlled by PI4KB through regulation of Schwann cell Golgi function. Proc Natl Acad Sci U S A 2020; 117:28102-28113. [PMID: 33106410 DOI: 10.1073/pnas.2007432117] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Better understanding myelination of peripheral nerves would benefit patients affected by peripheral neuropathies, including Charcot-Marie-Tooth disease. Little is known about the role the Golgi compartment plays in Schwann cell (SC) functions. Here, we studied the role of Golgi in myelination of peripheral nerves in mice through SC-specific genetic inactivation of phosphatidylinositol 4-kinase beta (PI4KB), a Golgi-associated lipid kinase. Sciatic nerves of such mice showed thinner myelin of large diameter axons and gross aberrations in myelin organization affecting the nodes of Ranvier, the Schmidt-Lanterman incisures, and Cajal bands. Nonmyelinating SCs showed a striking inability to engulf small diameter nerve fibers. SCs of mutant mice showed a distorted Golgi morphology and disappearance of OSBP at the cis-Golgi compartment, together with a complete loss of GOLPH3 from the entire Golgi. Accordingly, the cholesterol and sphingomyelin contents of sciatic nerves were greatly reduced and so was the number of caveolae observed in SCs. Although the conduction velocity of sciatic nerves of mutant mice showed an 80% decrease, the mice displayed only subtle impairment in their motor functions. Our analysis revealed that Golgi functions supported by PI4KB are critically important for proper myelination through control of lipid metabolism, protein glycosylation, and organization of microvilli in the nodes of Ranvier of peripheral nerves.
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9
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Otani Y, Ohno N, Cui J, Yamaguchi Y, Baba H. Upregulation of large myelin protein zero leads to Charcot-Marie-Tooth disease-like neuropathy in mice. Commun Biol 2020; 3:121. [PMID: 32170207 PMCID: PMC7070019 DOI: 10.1038/s42003-020-0854-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Accepted: 02/24/2020] [Indexed: 01/01/2023] Open
Abstract
Charcot-Marie-Tooth (CMT) disease is a hereditary neuropathy mainly caused by gene mutation of peripheral myelin proteins including myelin protein zero (P0, MPZ). Large myelin protein zero (L-MPZ) is an isoform of P0 that contains an extended polypeptide synthesized by translational readthrough at the C-terminus in tetrapods, including humans. The physiological role of L-MPZ and consequences of an altered L-MPZ/P0 ratio in peripheral myelin are not known. To clarify this, we used genome editing to generate a mouse line (L-MPZ mice) that produced L-MPZ instead of P0. Motor tests and electrophysiological, immunohistological, and electron microscopy analyses show that homozygous L-MPZ mice exhibit CMT-like phenotypes including thin and/or loose myelin, increased small-caliber axons, and disorganized axo-glial interactions. Heterozygous mice show a milder phenotype. These results highlight the importance of an appropriate L-MPZ/P0 ratio and show that aberrant readthrough of a myelin protein causes neuropathy.
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Affiliation(s)
- Yoshinori Otani
- Department of Molecular Neurobiology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Japan
| | - Nobuhiko Ohno
- Department of Anatomy, Division of Histology and Cell Biology, School of Medicine, Jichi Medical University, Shimotsuke, Japan
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Japan
| | - Jingjing Cui
- Department of Molecular Neurobiology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Japan
| | - Yoshihide Yamaguchi
- Department of Molecular Neurobiology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Japan.
| | - Hiroko Baba
- Department of Molecular Neurobiology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Japan
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10
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Raasakka A, Kursula P. Flexible Players within the Sheaths: The Intrinsically Disordered Proteins of Myelin in Health and Disease. Cells 2020; 9:cells9020470. [PMID: 32085570 PMCID: PMC7072810 DOI: 10.3390/cells9020470] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 02/16/2020] [Accepted: 02/16/2020] [Indexed: 02/07/2023] Open
Abstract
Myelin ensheathes selected axonal segments within the nervous system, resulting primarily in nerve impulse acceleration, as well as mechanical and trophic support for neurons. In the central and peripheral nervous systems, various proteins that contribute to the formation and stability of myelin are present, which also harbor pathophysiological roles in myelin disease. Many myelin proteins have common attributes, including small size, hydrophobic segments, multifunctionality, longevity, and regions of intrinsic disorder. With recent advances in protein biophysical characterization and bioinformatics, it has become evident that intrinsically disordered proteins (IDPs) are abundant in myelin, and their flexible nature enables multifunctionality. Here, we review known myelin IDPs, their conservation, molecular characteristics and functions, and their disease relevance, along with open questions and speculations. We place emphasis on classifying the molecular details of IDPs in myelin, and we correlate these with their various functions, including susceptibility to post-translational modifications, function in protein–protein and protein–membrane interactions, as well as their role as extended entropic chains. We discuss how myelin pathology can relate to IDPs and which molecular factors are potentially involved.
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Affiliation(s)
- Arne Raasakka
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, NO-5009 Bergen, Norway;
| | - Petri Kursula
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, NO-5009 Bergen, Norway;
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Aapistie 7A, FI-90220 Oulu, Finland
- Correspondence:
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11
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Park HT, Kim YH, Lee KE, Kim JK. Behind the pathology of macrophage-associated demyelination in inflammatory neuropathies: demyelinating Schwann cells. Cell Mol Life Sci 2019; 77:2497-2506. [PMID: 31884566 PMCID: PMC7320037 DOI: 10.1007/s00018-019-03431-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 12/16/2019] [Accepted: 12/18/2019] [Indexed: 03/11/2023]
Abstract
In inflammatory peripheral demyelinating disorders, demyelination represents segmental demyelination in which the myelin sheath of a myelinating Schwann cell (SC) is completely removed by macrophages or a partial myelin degeneration in the paranode occurring due to autoantibodies attacking the node/paranode. For the segmental demyelination from living myelin-forming SCs, macrophages infiltrate within the endoneurium and insinuate between myelin lamellae and the cytoplasm of SCs, and the myelin is then removed via phagocytosis. During the macrophage invasion into the SC cytoplasm from the node of Ranvier and internodal areas, the attacked SCs do not remain quiescent but transdifferentiate into inflammatory demyelinating SCs (iDSCs), which exhibit unique demyelination pathologies, such as myelin uncompaction from Schmidt-Lanterman incisures with myelin lamellae degeneration. The longitudinal extension of this self-myelin clearance process of iDSCs into the nodal region is associated with the degeneration of nodal microvilli and paranodal loops, which provides a potential locus for macrophage infiltration. In addition to the nodal intrusion, macrophages appear to be able to invade fenestrated internodal plasma membrane or the degenerated outer mesaxon of iDSC. These SC demyelination morphologies indicate that the SC reprogramming to iDSCs may be a prerequisite for macrophage-mediated inflammatory demyelination. In contrast, paranodal demyelination caused by autoantibodies to nodal/paranodal antigens does not result in iDSC-dependent macrophage infiltration and subsequent segmental demyelination. In the context of inflammatory demyelination, the novel perspective of iDSCs provides an important viewpoint to understand the pathophysiology of demyelinating peripheral neuropathies and establish diagnostic and therapeutic strategies.
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Affiliation(s)
- Hwan Tae Park
- Peripheral Neuropathy Research Center (PNRC), Dong-A University College of Medicine, Busan, 49201, South Korea. .,Department of Molecular Neuroscience, Dong-A University College of Medicine, Busan, 49201, Republic of Korea.
| | - Young Hee Kim
- Peripheral Neuropathy Research Center (PNRC), Dong-A University College of Medicine, Busan, 49201, South Korea
| | - Kyung Eun Lee
- Advanced Analysis Center, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul, 02792, South Korea
| | - Jong Kuk Kim
- Peripheral Neuropathy Research Center (PNRC), Dong-A University College of Medicine, Busan, 49201, South Korea.,Department of Neurology, Dong-A University College of Medicine, Busan, 49201, South Korea
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12
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Raasakka A, Linxweiler H, Brophy PJ, Sherman DL, Kursula P. Direct Binding of the Flexible C-Terminal Segment of Periaxin to β4 Integrin Suggests a Molecular Basis for CMT4F. Front Mol Neurosci 2019; 12:84. [PMID: 31024253 PMCID: PMC6465933 DOI: 10.3389/fnmol.2019.00084] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 03/19/2019] [Indexed: 11/13/2022] Open
Abstract
The process of myelination in the nervous system requires a coordinated formation of both transient and stable supramolecular complexes. Myelin-specific proteins play key roles in these assemblies, which may link membranes to each other or connect the myelinating cell cytoskeleton to the extracellular matrix. The myelin protein periaxin is known to play an important role in linking the Schwann cell cytoskeleton to the basal lamina through membrane receptors, such as the dystroglycan complex. Mutations that truncate periaxin from the C terminus cause demyelinating peripheral neuropathy, Charcot-Marie-Tooth (CMT) disease type 4F, indicating a function for the periaxin C-terminal region in myelination. We identified the cytoplasmic domain of β4 integrin as a specific high-affinity binding partner for periaxin. The C-terminal region of periaxin remains unfolded and flexible when bound to the third fibronectin type III domain of β4 integrin. Our data suggest that periaxin is able to link the Schwann cell cytoplasm to the basal lamina through a two-pronged interaction via different membrane protein complexes, which bind close to the N and C terminus of this elongated, flexible molecule.
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Affiliation(s)
- Arne Raasakka
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | | | - Peter J. Brophy
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Diane L. Sherman
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Petri Kursula
- Department of Biomedicine, University of Bergen, Bergen, Norway
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
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13
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Yamamoto T, Awano H, Zhang Z, Sakuma M, Kitaaki S, Matsumoto M, Nagai M, Sato I, Imanishi T, Hayashi N, Matsuo M, Iijima K, Saegusa J. Cardiac Dysfunction in Duchenne Muscular Dystrophy Is Less Frequent in Patients With Mutations in the Dystrophin Dp116 Coding Region Than in Other Regions. CIRCULATION-GENOMIC AND PRECISION MEDICINE 2019; 11:e001782. [PMID: 29874176 PMCID: PMC6319568 DOI: 10.1161/circgen.117.001782] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 11/07/2017] [Indexed: 01/16/2023]
Abstract
Supplemental Digital Content is available in the text. Background: Duchenne muscular dystrophy (DMD), the most common inherited muscular disease in childhood, is caused by dystrophin deficiency because of mutations in the DMD gene. Although DMD is characterized by fatal progressive muscle wasting, cardiomyopathy is the most important nonmuscle symptom threatening the life of patients with DMD. The relationship between cardiac involvement and dystrophin isoforms has not been analyzed. Methods and Results: The results of 1109 echocardiograms obtained from 181 Japanese DMD patients with confirmed mutations in the DMD gene were retrospectively analyzed. Patients showed an age-related decline in left ventricular ejection fraction. Patients were divided by patterns of dystrophin isoform deficiency into 5 groups. The cardiac dysfunction-free survival was significantly higher in the group with mutations in the Dp116 coding region than the others, whereas no significant differences in the other 3 groups. At age 25 years, the cardiac dysfunction-free rate was 0.6 in the Dp116 group, but only 0.1 in others. PCR amplification of Dp116 transcript in human cardiac muscle indicated promoter activation. Conclusions: Left ventricular ejection fraction in DMD declined stepwise with age. Cardiac dysfunction was less frequent in Dp116-deficient than other patients with DMD. Dp116 transcript was identified in human cardiac muscle for the first time. These results indicate that Dp116 is associated with cardiac involvement in DMD.
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Affiliation(s)
- Tetsushi Yamamoto
- From the Department of Clinical Laboratory, Kobe University Hospital, Kobe, Japan (T.Y., S.K., I.S., T.I., N.H., J.S.); Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan (H.A., M. Matsumoto, M.N., K.I.); Department of Pathology, Medical School of Nankai University, Tianjin, China (Z.Z.); Department of Physical Therapy, Faculty of Rehabilitation, Kobe Gakuin University, Kobe, Japan (Z.Z., M. Matsuo); and Department of Clinical Epidemiology, Hyogo College of Medicine, Nishinomiya, Japan (M.E.-S.)
| | - Hiroyuki Awano
- From the Department of Clinical Laboratory, Kobe University Hospital, Kobe, Japan (T.Y., S.K., I.S., T.I., N.H., J.S.); Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan (H.A., M. Matsumoto, M.N., K.I.); Department of Pathology, Medical School of Nankai University, Tianjin, China (Z.Z.); Department of Physical Therapy, Faculty of Rehabilitation, Kobe Gakuin University, Kobe, Japan (Z.Z., M. Matsuo); and Department of Clinical Epidemiology, Hyogo College of Medicine, Nishinomiya, Japan (M.E.-S.)
| | - Zhujun Zhang
- From the Department of Clinical Laboratory, Kobe University Hospital, Kobe, Japan (T.Y., S.K., I.S., T.I., N.H., J.S.); Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan (H.A., M. Matsumoto, M.N., K.I.); Department of Pathology, Medical School of Nankai University, Tianjin, China (Z.Z.); Department of Physical Therapy, Faculty of Rehabilitation, Kobe Gakuin University, Kobe, Japan (Z.Z., M. Matsuo); and Department of Clinical Epidemiology, Hyogo College of Medicine, Nishinomiya, Japan (M.E.-S.)
| | - Mio Sakuma
- From the Department of Clinical Laboratory, Kobe University Hospital, Kobe, Japan (T.Y., S.K., I.S., T.I., N.H., J.S.); Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan (H.A., M. Matsumoto, M.N., K.I.); Department of Pathology, Medical School of Nankai University, Tianjin, China (Z.Z.); Department of Physical Therapy, Faculty of Rehabilitation, Kobe Gakuin University, Kobe, Japan (Z.Z., M. Matsuo); and Department of Clinical Epidemiology, Hyogo College of Medicine, Nishinomiya, Japan (M.E.-S.)
| | - Shoko Kitaaki
- From the Department of Clinical Laboratory, Kobe University Hospital, Kobe, Japan (T.Y., S.K., I.S., T.I., N.H., J.S.); Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan (H.A., M. Matsumoto, M.N., K.I.); Department of Pathology, Medical School of Nankai University, Tianjin, China (Z.Z.); Department of Physical Therapy, Faculty of Rehabilitation, Kobe Gakuin University, Kobe, Japan (Z.Z., M. Matsuo); and Department of Clinical Epidemiology, Hyogo College of Medicine, Nishinomiya, Japan (M.E.-S.)
| | - Masaaki Matsumoto
- From the Department of Clinical Laboratory, Kobe University Hospital, Kobe, Japan (T.Y., S.K., I.S., T.I., N.H., J.S.); Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan (H.A., M. Matsumoto, M.N., K.I.); Department of Pathology, Medical School of Nankai University, Tianjin, China (Z.Z.); Department of Physical Therapy, Faculty of Rehabilitation, Kobe Gakuin University, Kobe, Japan (Z.Z., M. Matsuo); and Department of Clinical Epidemiology, Hyogo College of Medicine, Nishinomiya, Japan (M.E.-S.)
| | - Masashi Nagai
- From the Department of Clinical Laboratory, Kobe University Hospital, Kobe, Japan (T.Y., S.K., I.S., T.I., N.H., J.S.); Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan (H.A., M. Matsumoto, M.N., K.I.); Department of Pathology, Medical School of Nankai University, Tianjin, China (Z.Z.); Department of Physical Therapy, Faculty of Rehabilitation, Kobe Gakuin University, Kobe, Japan (Z.Z., M. Matsuo); and Department of Clinical Epidemiology, Hyogo College of Medicine, Nishinomiya, Japan (M.E.-S.)
| | - Itsuko Sato
- From the Department of Clinical Laboratory, Kobe University Hospital, Kobe, Japan (T.Y., S.K., I.S., T.I., N.H., J.S.); Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan (H.A., M. Matsumoto, M.N., K.I.); Department of Pathology, Medical School of Nankai University, Tianjin, China (Z.Z.); Department of Physical Therapy, Faculty of Rehabilitation, Kobe Gakuin University, Kobe, Japan (Z.Z., M. Matsuo); and Department of Clinical Epidemiology, Hyogo College of Medicine, Nishinomiya, Japan (M.E.-S.)
| | - Takamitsu Imanishi
- From the Department of Clinical Laboratory, Kobe University Hospital, Kobe, Japan (T.Y., S.K., I.S., T.I., N.H., J.S.); Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan (H.A., M. Matsumoto, M.N., K.I.); Department of Pathology, Medical School of Nankai University, Tianjin, China (Z.Z.); Department of Physical Therapy, Faculty of Rehabilitation, Kobe Gakuin University, Kobe, Japan (Z.Z., M. Matsuo); and Department of Clinical Epidemiology, Hyogo College of Medicine, Nishinomiya, Japan (M.E.-S.)
| | - Nobuhide Hayashi
- From the Department of Clinical Laboratory, Kobe University Hospital, Kobe, Japan (T.Y., S.K., I.S., T.I., N.H., J.S.); Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan (H.A., M. Matsumoto, M.N., K.I.); Department of Pathology, Medical School of Nankai University, Tianjin, China (Z.Z.); Department of Physical Therapy, Faculty of Rehabilitation, Kobe Gakuin University, Kobe, Japan (Z.Z., M. Matsuo); and Department of Clinical Epidemiology, Hyogo College of Medicine, Nishinomiya, Japan (M.E.-S.)
| | - Masafumi Matsuo
- From the Department of Clinical Laboratory, Kobe University Hospital, Kobe, Japan (T.Y., S.K., I.S., T.I., N.H., J.S.); Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan (H.A., M. Matsumoto, M.N., K.I.); Department of Pathology, Medical School of Nankai University, Tianjin, China (Z.Z.); Department of Physical Therapy, Faculty of Rehabilitation, Kobe Gakuin University, Kobe, Japan (Z.Z., M. Matsuo); and Department of Clinical Epidemiology, Hyogo College of Medicine, Nishinomiya, Japan (M.E.-S.).
| | - Kazumoto Iijima
- From the Department of Clinical Laboratory, Kobe University Hospital, Kobe, Japan (T.Y., S.K., I.S., T.I., N.H., J.S.); Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan (H.A., M. Matsumoto, M.N., K.I.); Department of Pathology, Medical School of Nankai University, Tianjin, China (Z.Z.); Department of Physical Therapy, Faculty of Rehabilitation, Kobe Gakuin University, Kobe, Japan (Z.Z., M. Matsuo); and Department of Clinical Epidemiology, Hyogo College of Medicine, Nishinomiya, Japan (M.E.-S.)
| | - Jun Saegusa
- From the Department of Clinical Laboratory, Kobe University Hospital, Kobe, Japan (T.Y., S.K., I.S., T.I., N.H., J.S.); Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan (H.A., M. Matsumoto, M.N., K.I.); Department of Pathology, Medical School of Nankai University, Tianjin, China (Z.Z.); Department of Physical Therapy, Faculty of Rehabilitation, Kobe Gakuin University, Kobe, Japan (Z.Z., M. Matsuo); and Department of Clinical Epidemiology, Hyogo College of Medicine, Nishinomiya, Japan (M.E.-S.)
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Murakami T, Sunada Y. Schwann Cell and the Pathogenesis of Charcot–Marie–Tooth Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1190:301-321. [DOI: 10.1007/978-981-32-9636-7_19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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15
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Erwig MS, Hesse D, Jung RB, Uecker M, Kusch K, Tenzer S, Jahn O, Werner HB. Myelin: Methods for Purification and Proteome Analysis. Methods Mol Biol 2019; 1936:37-63. [PMID: 30820892 DOI: 10.1007/978-1-4939-9072-6_3] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Molecular characterization of myelin is a prerequisite for understanding the normal structure of the axon/myelin-unit in the healthy nervous system and abnormalities in myelin-related disorders. However, reliable molecular profiles necessitate very pure myelin membranes, in particular when considering the power of highly sensitive "omics"-data acquisition methods. Here, we recapitulate the history and recent applications of myelin purification. We then provide our laboratory protocols for the biochemical isolation of a highly pure myelin-enriched fraction from mouse brains and for its proteomic analysis. We also supply methodological modifications when investigating posttranslational modifications, RNA, or myelin from peripheral nerves. Notably, technical advancements in solubilizing myelin are beneficial for gel-based and gel-free myelin proteome analyses. We conclude this article by exemplifying the exceptional power of label-free proteomics in the mass-spectrometric quantification of myelin proteins.
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Affiliation(s)
- Michelle S Erwig
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Goettingen, Germany
| | - Dörte Hesse
- Proteomics Group, Max Planck Institute of Experimental Medicine, Goettingen, Germany
| | - Ramona B Jung
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Goettingen, Germany
| | - Marina Uecker
- Proteomics Group, Max Planck Institute of Experimental Medicine, Goettingen, Germany
| | - Kathrin Kusch
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Goettingen, Germany
| | - Stefan Tenzer
- Institute of Immunology, University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Olaf Jahn
- Proteomics Group, Max Planck Institute of Experimental Medicine, Goettingen, Germany.
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Goettingen, Germany.
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16
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Expression of periaxin (PRX) specifically in the human cerebrovascular system: PDZ domain-mediated strengthening of endothelial barrier function. Sci Rep 2018; 8:10042. [PMID: 29968755 PMCID: PMC6030167 DOI: 10.1038/s41598-018-28190-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 06/13/2018] [Indexed: 01/01/2023] Open
Abstract
Regulation of cerebral endothelial cell function plays an essential role in changes in blood-brain barrier permeability. Proteins that are important for establishment of endothelial tight junctions have emerged as critical molecules, and PDZ domain containing-molecules are among the most important. We have discovered that the PDZ-domain containing protein periaxin (PRX) is expressed in human cerebral endothelial cells. Surprisingly, PRX protein is not detected in brain endothelium in other mammalian species, suggesting that it could confer human-specific vascular properties. In endothelial cells, PRX is predominantly localized to the nucleus and not tight junctions. Transcriptome analysis shows that PRX expression suppresses, by at least 50%, a panel of inflammatory markers, of which 70% are Type I interferon response genes; only four genes were significantly activated by PRX expression. When expressed in mouse endothelial cells, PRX strengthens barrier function, significantly increases transendothelial electrical resistance (~35%; p < 0.05), and reduces the permeability of a wide range of molecules. The PDZ domain of PRX is necessary and sufficient for its barrier enhancing properties, since a splice variant (S-PRX) that contains only the PDZ domain, also increases barrier function. PRX also attenuates the permeability enhancing effects of lipopolysaccharide. Collectively, these studies suggest that PRX could potentially regulate endothelial homeostasis in human cerebral endothelial cells by modulating inflammatory gene programs.
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17
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Sherman DL, Brophy PJ. A murine model of Charcot-Marie-Tooth disease 4F reveals a role for the C-terminus of periaxin in the formation and stabilization of Cajal bands. Wellcome Open Res 2018; 3:20. [PMID: 29623298 PMCID: PMC5861512 DOI: 10.12688/wellcomeopenres.13673.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/23/2018] [Indexed: 11/20/2022] Open
Abstract
Charcot-Marie-Tooth (CMT) disease comprises up to 80 monogenic inherited neuropathies of the peripheral nervous system (PNS) that collectively result in demyelination and axon degeneration. The majority of CMT disease is primarily either dysmyelinating or demyelinating in which mutations affect the ability of Schwann cells to either assemble or stabilize peripheral nerve myelin. CMT4F is a recessive demyelinating form of the disease caused by mutations in the
Periaxin (
PRX) gene
. Periaxin (Prx) interacts with Dystrophin Related Protein 2 (Drp2) in an adhesion complex with the laminin receptor Dystroglycan (Dag). In mice the Prx/Drp2/Dag complex assembles adhesive domains at the interface between the abaxonal surface of the myelin sheath and the cytoplasmic surface of the Schwann cell plasma membrane. Assembly of these appositions causes the formation of cytoplasmic channels called Cajal bands beneath the surface of the Schwann cell plasma membrane. Loss of either Periaxin or Drp2 disrupts the appositions and causes CMT in both mouse and man. In a mouse model of CMT4F, complete loss of Periaxin first prevents normal Schwann cell elongation resulting in abnormally short internodal distances which can reduce nerve conduction velocity, and subsequently precipitates demyelination. Distinct functional domains responsible for Periaxin homodimerization and interaction with Drp2 to form the Prx/Drp2/Dag complex have been identified at the N-terminus of Periaxin. However, CMT4F can also be caused by a mutation that results in the truncation of Periaxin at the extreme C-terminus with the loss of 391 amino acids. By modelling this in mice, we show that loss of the C-terminus of Periaxin results in a surprising reduction in Drp2. This would be predicted to cause the observed instability of both appositions and myelin, and contribute significantly to the clinical phenotype in CMT4F.
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Affiliation(s)
- Diane L Sherman
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Peter J Brophy
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
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18
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Murphy S, Zweyer M, Henry M, Meleady P, Mundegar RR, Swandulla D, Ohlendieck K. Proteomic analysis of the sarcolemma-enriched fraction from dystrophic mdx-4cv skeletal muscle. J Proteomics 2018; 191:212-227. [PMID: 29408692 DOI: 10.1016/j.jprot.2018.01.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 01/12/2018] [Accepted: 01/28/2018] [Indexed: 02/07/2023]
Abstract
The highly progressive neuromuscular disorder dystrophinopathy is triggered by primary abnormalities in the Dmd gene, which causes cytoskeletal instability and loss of sarcolemmal integrity. Comparative organellar proteomics was employed to identify sarcolemma-associated proteins with an altered concentration in dystrophic muscle tissue from the mdx-4cv mouse model of dystrophinopathy. A lectin agglutination method was used to prepare a sarcolemma-enriched fraction and resulted in the identification of 190 significantly changed protein species. Proteomics established differential expression patterns for key components of the muscle plasma membrane, cytoskeletal network, extracellular matrix, metabolic pathways, cellular stress response, protein synthesis, immune response and neuromuscular junction. The deficiency in dystrophin and drastic reduction in dystrophin-associated proteins appears to trigger (i) enhanced membrane repair involving myoferlin, dysferlin and annexins, (ii) increased protein synthesis and the compensatory up-regulation of cytoskeletal proteins, (iii) the decrease in the scaffolding protein periaxin and myelin PO involved in myelination of motor neurons, (iv) complex changes in bioenergetic pathways, (v) elevated levels of molecular chaperones to prevent proteotoxic effects, (vi) increased collagen deposition causing reactive myofibrosis, (vii) disturbed ion homeostasis at the sarcolemma and associated membrane systems, and (viii) a robust inflammatory response by the innate immune system in response to chronic muscle damage. SIGNIFICANCE: Duchenne muscular dystrophy is a devastating muscle wasting disease and represents the most frequently inherited neuromuscular disorder in humans. Genetic abnormalities in the Dmd gene cause a loss of sarcolemmal integrity and highly progressive muscle fibre degeneration. Changes in the neuromuscular system are associated with necrosis, fibrosis and inflammation. In order to evaluate secondary changes in the sarcolemma membrane system due to the lack of the membrane cytoskeletal protein dystrophin, comparative organellar proteomics was used to study the mdx-4cv mouse model of dystrophinopathy. Mass spectrometric analyses identified a variety of altered components of the extracellular matrix-sarcolemma-cytoskeleton axis in dystrophic muscles. This included proteins involved in membrane repair, cytoskeletal restoration, calcium homeostasis, cellular signalling, stress response, neuromuscular transmission and reactive myofibrosis, as well as immune cell infiltration. These pathobiochemical alterations agree with the idea of highly complex secondary changes in X-linked muscular dystrophy and support the concept that micro-rupturing of the dystrophin-deficient plasma membrane is at the core of muscle wasting pathology.
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Affiliation(s)
- Sandra Murphy
- Department of Biology, Maynooth University, National University of Ireland, Maynooth, Co. Kildare, Ireland
| | - Margit Zweyer
- Institute of Physiology II, University of Bonn, D-53115 Bonn, Germany
| | - Michael Henry
- National Institute for Cellular Biotechnology, Dublin City University, Dublin 9, Ireland
| | - Paula Meleady
- National Institute for Cellular Biotechnology, Dublin City University, Dublin 9, Ireland
| | - Rustam R Mundegar
- Institute of Physiology II, University of Bonn, D-53115 Bonn, Germany
| | - Dieter Swandulla
- Institute of Physiology II, University of Bonn, D-53115 Bonn, Germany
| | - Kay Ohlendieck
- Department of Biology, Maynooth University, National University of Ireland, Maynooth, Co. Kildare, Ireland.
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19
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Roda RH, McCray BA, Klein CJ, Hoke A. Novel hemizygous nonsense mutation in DRP2 is associated with inherited neuropathy. NEUROLOGY-GENETICS 2018; 4:e220. [PMID: 29473052 PMCID: PMC5820600 DOI: 10.1212/nxg.0000000000000220] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 12/12/2017] [Indexed: 11/18/2022]
Affiliation(s)
- Ricardo H Roda
- Department of Neurology (R.H.R., B.A.M., A.H.), Johns Hopkins University School of Medicine, Baltimore, MD; and Department of Neurology (C.J.K.), Mayo Clinic, Rochester, MN
| | - Brett A McCray
- Department of Neurology (R.H.R., B.A.M., A.H.), Johns Hopkins University School of Medicine, Baltimore, MD; and Department of Neurology (C.J.K.), Mayo Clinic, Rochester, MN
| | - Christopher J Klein
- Department of Neurology (R.H.R., B.A.M., A.H.), Johns Hopkins University School of Medicine, Baltimore, MD; and Department of Neurology (C.J.K.), Mayo Clinic, Rochester, MN
| | - Ahmet Hoke
- Department of Neurology (R.H.R., B.A.M., A.H.), Johns Hopkins University School of Medicine, Baltimore, MD; and Department of Neurology (C.J.K.), Mayo Clinic, Rochester, MN
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20
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Ackerman SD, Luo R, Poitelon Y, Mogha A, Harty BL, D'Rozario M, Sanchez NE, Lakkaraju AKK, Gamble P, Li J, Qu J, MacEwan MR, Ray WZ, Aguzzi A, Feltri ML, Piao X, Monk KR. GPR56/ADGRG1 regulates development and maintenance of peripheral myelin. J Exp Med 2018; 215:941-961. [PMID: 29367382 PMCID: PMC5839751 DOI: 10.1084/jem.20161714] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Revised: 11/03/2017] [Accepted: 12/15/2017] [Indexed: 01/26/2023] Open
Abstract
This study identifies GPR56/ADGRG1 as a conserved regulator of peripheral nervous system myelination and defines a novel interacting partner of GPR56: plectin. This study is directly relevant to human health because mutations in GPR56 and PLECTIN cause diseases with neuropathic symptoms. Myelin is a multilamellar sheath generated by specialized glia called Schwann cells (SCs) in the peripheral nervous system (PNS), which serves to protect and insulate axons for rapid neuronal signaling. In zebrafish and rodent models, we identify GPR56/ADGRG1 as a conserved regulator of PNS development and health. We demonstrate that, during SC development, GPR56-dependent RhoA signaling promotes timely radial sorting of axons. In the mature PNS, GPR56 is localized to distinct SC cytoplasmic domains, is required to establish proper myelin thickness, and facilitates organization of the myelin sheath. Furthermore, we define plectin—a scaffolding protein previously linked to SC domain organization, myelin maintenance, and a series of disorders termed “plectinopathies”—as a novel interacting partner of GPR56. Finally, we show that Gpr56 mutants develop progressive neuropathy-like symptoms, suggesting an underlying mechanism for peripheral defects in some human patients with GPR56 mutations. In sum, we define Gpr56 as a new regulator in the development and maintenance of peripheral myelin.
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Affiliation(s)
- Sarah D Ackerman
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO
| | - Rong Luo
- Division of Newborn Medicine, Department of Medicine, Children's Hospital and Harvard Medical School, Boston, MA
| | - Yannick Poitelon
- Departments of Biochemistry and Neurology, Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY
| | - Amit Mogha
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO
| | - Breanne L Harty
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO
| | - Mitchell D'Rozario
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO
| | - Nicholas E Sanchez
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO
| | | | - Paul Gamble
- Department of Neurosurgery, Washington University School of Medicine, St. Louis, MO
| | - Jun Li
- Department of Pharmaceutical Sciences, University at Buffalo, State University of New York, Buffalo, NY.,New York State Center of Excellence in Bioinformatics and Life Sciences, Buffalo, NY
| | - Jun Qu
- Department of Pharmaceutical Sciences, University at Buffalo, State University of New York, Buffalo, NY.,New York State Center of Excellence in Bioinformatics and Life Sciences, Buffalo, NY
| | - Matthew R MacEwan
- Department of Neurosurgery, Washington University School of Medicine, St. Louis, MO.,Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO
| | - Wilson Zachary Ray
- Department of Neurosurgery, Washington University School of Medicine, St. Louis, MO.,Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO
| | - Adriano Aguzzi
- Institute of Neuropathology, University of Zurich, Zürich, Switzerland
| | - M Laura Feltri
- Departments of Biochemistry and Neurology, Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY
| | - Xianhua Piao
- Division of Newborn Medicine, Department of Medicine, Children's Hospital and Harvard Medical School, Boston, MA
| | - Kelly R Monk
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO
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21
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Cervellini I, Galino J, Zhu N, Allen S, Birchmeier C, Bennett DL. Sustained MAPK/ERK Activation in Adult Schwann Cells Impairs Nerve Repair. J Neurosci 2018; 38:679-690. [PMID: 29217688 PMCID: PMC5777114 DOI: 10.1523/jneurosci.2255-17.2017] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 09/29/2017] [Accepted: 10/19/2017] [Indexed: 11/21/2022] Open
Abstract
The MAPK/ERK pathway has a critical role in PNS development. It is required for Schwann cell (SC) differentiation and myelination; sustained embryonic MAPK/ERK activation in SCs enhances myelin growth overcoming signals that normally end myelination. Excess activation of this pathway can be maladaptive as in adulthood acute strong activation of MAPK/ERK has been shown to cause SC dedifferentiation and demyelination. We used a mouse model (including male and female animals) in which the gain-of-function MEK1DD allele produces sustained MAPK/ERK activation in adult SCs, and we determined the impact of such activation on nerve repair. In the uninjured nerve, MAPK/ERK activation neither impaired myelin nor reactivated myelination. However, in the injured nerve it was detrimental and resulted in delayed repair and functional recovery. In the early phase of injury, the rate of myelin clearance was faster. Four weeks following injury, when nerve repair is normally advanced, myelinated axons of MEK1DD mutants demonstrated higher rates of myelin decompaction, a reduced number of Cajal bands. and decreased internodal length. We noted the presence of abnormal Remak bundles with long SCs processes and reduced numbers of C-fibers/Remak bundle. Both the total number of regenerating axons and the intraepidermal nerve fiber density in the skin were reduced. Sustained activation of MAPK/ERK in adult SCs is therefore deleterious to successful nerve repair, emphasizing the differences in the signaling processes coordinating nerve development and repair. Our results also underline the key role of SCs in axon regeneration and successful target reinnervation.SIGNIFICANCE STATEMENT The MAPK/ERK pathway promotes developmental myelination and its sustained activation in SCs induced continuous myelin growth, compensating for the absence of essential myelination signals. However, the strength of activation is fundamental because acute strong induction of MAPK/ERK in adulthood induces demyelination. What has been unknown is the effect of a mild but sustained MAPK/ERK activation in SCs on nerve repair in adulthood. This promoted myelin clearance but led to abnormalities in nonmyelinating and myelinating SCs in the later phases of nerve repair, resulting in slowed axon regeneration, cutaneous reinnervation, and functional recovery. Our results emphasize the distinct role of the MAPK/ERK pathway in developmental myelination versus remyelination and the importance of signaling between SCs and axons for successful axon regeneration.
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Affiliation(s)
- Ilaria Cervellini
- The Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom, and
| | - Jorge Galino
- The Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom, and
| | - Ning Zhu
- The Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom, and
| | - Shannen Allen
- The Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom, and
| | - Carmen Birchmeier
- Developmental Biology/Signal Transduction Group, Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz Society, 13125 Berlin, Germany
| | - David L Bennett
- The Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom, and
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22
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Duchesne M, Mathis S, Richard L, Magdelaine C, Corcia P, Nouioua S, Tazir M, Magy L, Vallat JM. Nerve Biopsy Is Still Useful in Some Inherited Neuropathies. J Neuropathol Exp Neurol 2017; 77:88-99. [DOI: 10.1093/jnen/nlx111] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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23
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Matsuo M, Awano H, Matsumoto M, Nagai M, Kawaguchi T, Zhang Z, Nishio H. Dystrophin Dp116: A yet to Be Investigated Product of the Duchenne Muscular Dystrophy Gene. Genes (Basel) 2017; 8:genes8100251. [PMID: 28974057 PMCID: PMC5664101 DOI: 10.3390/genes8100251] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 09/26/2017] [Indexed: 12/12/2022] Open
Abstract
The Duchenne muscular dystrophy (DMD) gene is one of the largest genes in the human genome. The gene exhibits a complex arrangement of seven alternative promoters, which drive the expression of three full length and four shorter isoforms. Dp116, the second smallest product of the DMD gene, is a Schwann cell-specific isoform encoded by a transcript corresponding to DMD exons 56–79, starting from a promoter/exon S1 within intron 55. The physiological roles of Dp116 are poorly understood, because of its extensive homology with other isoforms and its expression in specific tissues. This review summarizes studies on Dp116, focusing on clinical findings and alternative activation of the upstream translation initiation codon that is predicted to produce Dp118.
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Affiliation(s)
- Masafumi Matsuo
- Department of Physical Therapy, Faculty of Rehabilitation, Kobe Gakuin University, Kobe 651-2180, Japan.
| | - Hiroyuki Awano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan.
| | - Masaaki Matsumoto
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan.
| | - Masashi Nagai
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan.
| | - Tatsuya Kawaguchi
- Biomedical Analysis and Pathology Research Group, Discovery Science and Technology Department, Daiichi Sankyo RD Novare Co., Tokyo 134-8630, Japan.
| | - Zhujun Zhang
- Department of Physical Therapy, Faculty of Rehabilitation, Kobe Gakuin University, Kobe 651-2180, Japan.
| | - Hisahide Nishio
- Department of Community Medicine and Social Healthcare Sciences, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan.
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24
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Schwann Cell O-GlcNAc Glycosylation Is Required for Myelin Maintenance and Axon Integrity. J Neurosci 2017; 36:9633-46. [PMID: 27629714 PMCID: PMC5039245 DOI: 10.1523/jneurosci.1235-16.2016] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 07/25/2016] [Indexed: 12/29/2022] Open
Abstract
UNLABELLED Schwann cells (SCs), ensheathing glia of the peripheral nervous system, support axonal survival and function. Abnormalities in SC metabolism affect their ability to provide this support and maintain axon integrity. To further interrogate this metabolic influence on axon-glial interactions, we generated OGT-SCKO mice with SC-specific deletion of the metabolic/nutrient sensing protein O-GlcNAc transferase that mediates the O-linked addition of N-acetylglucosamine (GlcNAc) moieties to Ser and Thr residues. The OGT-SCKO mice develop tomaculous demyelinating neuropathy characterized by focal thickenings of the myelin sheath (tomacula), progressive demyelination, axonal loss, and motor and sensory nerve dysfunction. Proteomic analysis identified more than 100 O-GlcNAcylated proteins in rat sciatic nerve, including Periaxin (PRX), a myelin protein whose mutation causes inherited neuropathy in humans. PRX lacking O-GlcNAcylation is mislocalized within the myelin sheath of these mutant animals. Furthermore, phenotypes of OGT-SCKO and Prx-deficient mice are very similar, suggesting that metabolic control of PRX O-GlcNAcylation is crucial for myelin maintenance and axonal integrity. SIGNIFICANCE STATEMENT The nutrient sensing protein O-GlcNAc transferase (OGT) mediates post-translational O-linked N-acetylglucosamine (GlcNAc) modification. Here we find that OGT functions in Schwann cells (SCs) to maintain normal myelin and prevent axonal loss. SC-specific deletion of OGT (OGT-SCKO mice) causes a tomaculous demyelinating neuropathy accompanied with progressive axon degeneration and motor and sensory nerve dysfunction. We also found Periaxin (PRX), a myelin protein whose mutation causes inherited neuropathy in humans, is O-GlcNAcylated. Importantly, phenotypes of OGT-SCKO and Prx mutant mice are very similar, implying that compromised PRX function contributes to the neuropathy of OGT-SCKO mice. This study will be useful in understanding how SC metabolism contributes to PNS function and in developing new strategies for treating peripheral neuropathy by targeting SC function.
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25
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Jones MR, Villalón E, Northcutt AJ, Calcutt NA, Garcia ML. Differential effects of myostatin deficiency on motor and sensory axons. Muscle Nerve 2017; 56:E100-E107. [PMID: 28073155 DOI: 10.1002/mus.25570] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 01/04/2017] [Accepted: 01/08/2017] [Indexed: 11/07/2022]
Abstract
INTRODUCTION Deletion of myostatin in mice (MSTN-/- ) alters structural properties of peripheral axons. However, properties like axon diameter and myelin thickness were analyzed in mixed nerves, so it is unclear whether loss of myostatin affects motor, sensory, or both types of axons. METHODS Using the MSTN-/- mouse model, we analyzed the effects of increasing the number of muscle fibers on axon diameter, myelin thickness, and internode length in motor and sensory axons. RESULTS Axon diameter and myelin thickness were increased in motor axons of MSTN-/- mice without affecting internode length or axon number. The number of sensory axons was increased without affecting their structural properties. DISCUSSION These results suggest that motor and sensory axons establish structural properties by independent mechanisms. Moreover, in motor axons, instructive cues from the neuromuscular junction may play a role in co-regulating axon diameter and myelin thickness, whereas internode length is established independently. Muscle Nerve 56: E100-E107, 2017.
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Affiliation(s)
- Maria R Jones
- Department of Biological Sciences, University of Missouri, Columbia, Missouri, USA.,C.S. Bond Life Sciences Center, University of Missouri, 1201 East Rollins Road, Columbia, Missouri, 65211, USA
| | - Eric Villalón
- Department of Biological Sciences, University of Missouri, Columbia, Missouri, USA.,C.S. Bond Life Sciences Center, University of Missouri, 1201 East Rollins Road, Columbia, Missouri, 65211, USA
| | - Adam J Northcutt
- Department of Biological Sciences, University of Missouri, Columbia, Missouri, USA
| | - Nigel A Calcutt
- Department of Pathology, University of California San Diego, La Jolla, California, USA
| | - Michael L Garcia
- Department of Biological Sciences, University of Missouri, Columbia, Missouri, USA.,C.S. Bond Life Sciences Center, University of Missouri, 1201 East Rollins Road, Columbia, Missouri, 65211, USA
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26
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Yang Y, Liang M, Shi Y. Retracted Article: Self-association of L-periaxin occurs via its acidic domain and NLS2/NLS3, and affects its trafficking in RSC96 cells. RSC Adv 2017. [DOI: 10.1039/c7ra06853k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Periaxin (PRX) protein was first identified in myelinating Schwann cells through the screening of cytoskeleton-associated proteins in peripheral nerve myelination.
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Affiliation(s)
- Yenan Yang
- Institute of Biotechnology
- Key Laboratory of Chemical Biology
- Molecular Engineering of Ministry of Education
- Shanxi University
- Taiyuan 030006
| | - Min Liang
- Institute of Biotechnology
- Key Laboratory of Chemical Biology
- Molecular Engineering of Ministry of Education
- Shanxi University
- Taiyuan 030006
| | - Yawei Shi
- Institute of Biotechnology
- Key Laboratory of Chemical Biology
- Molecular Engineering of Ministry of Education
- Shanxi University
- Taiyuan 030006
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27
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Rao PV, Maddala R. Ankyrin-B in lens architecture and biomechanics: Just not tethering but more. BIOARCHITECTURE 2016; 6:39-45. [PMID: 27044909 DOI: 10.1080/19490992.2016.1156284] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The ankyrins are a family of well-characterized metazoan adaptor proteins that play a key role in linking various membrane-spanning proteins to the underlying spectrin-actin cytoskeleton; a mechanistic understanding of their role in tissue architecture and mechanics, however, remains elusive. Here we comment on a recent study demonstrating a key role for ankyrin-B in maintaining the hexagonal shape and radial alignment of ocular lens fiber cells by regulating the membrane organization of periaxin, dystrophins/dystroglycan, NrCAM and spectrin-actin network of proteins, and revealing that ankyrin-B deficiency impairs fiber cell shape and mechanical properties of the ocular lens. These observations indicate that ankyrin-B plays an important role in maintaining tissue cytoarchitecture, cell shape and biomechanical properties via engaging in key protein: protein interactions required for membrane anchoring and organization of the spectrin-actin skeleton, scaffolding proteins and cell adhesive proteins.
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Affiliation(s)
- Ponugoti Vasantha Rao
- a Department of Ophthalmology , Duke University School of Medicine , Durham , NC , USA.,b Department of Pharmacology & Cancer Biology , Duke University School of Medicine , Durham , NC , USA
| | - Rupalatha Maddala
- a Department of Ophthalmology , Duke University School of Medicine , Durham , NC , USA
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28
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Optimal myelin elongation relies on YAP activation by axonal growth and inhibition by Crb3/Hippo pathway. Nat Commun 2016; 7:12186. [PMID: 27435623 PMCID: PMC4961766 DOI: 10.1038/ncomms12186] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 06/09/2016] [Indexed: 01/24/2023] Open
Abstract
Fast nerve conduction relies on successive myelin segments that electrically isolate axons. Segment geometry—diameter and length—is critical for the optimization of nerve conduction and the molecular mechanisms allowing this optimized geometry are partially known. We show here that peripheral myelin elongation is dynamically regulated by stimulation of YAP (Yes-associated protein) transcription cofactor activity during axonal elongation and limited by inhibition of YAP activity via the Hippo pathway. YAP promotes myelin and non-myelin genes transcription while the polarity protein Crb3, localized at the tips of the myelin sheath, activates the Hippo pathway to temper YAP activity, therefore allowing for optimal myelin growth. Dystrophic Dy2j/2j mice mimicking human peripheral neuropathy with reduced internodal lengths have decreased nuclear YAP which, when corrected, leads to longer internodes. These data show a novel mechanism controlling myelin growth and nerve conduction, and provide a molecular ground for disease with short myelin segments. Molecular mechanisms regulating optimal myelin geometry are only partially understood. Here authors show that peripheral myelin growth is orchestrated by the Crb3/Hippo/YAP pathway, and that defects in YAP activation may underlie peripheral neuropathies caused by shorter myelin.
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Vijay S, Chiu M, Dacks JB, Roberts RC. Exclusive expression of the Rab11 effector SH3TC2 in Schwann cells links integrin-α6 and myelin maintenance to Charcot-Marie-Tooth disease type 4C. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1862:1279-90. [PMID: 27068304 PMCID: PMC4879868 DOI: 10.1016/j.bbadis.2016.04.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 03/24/2016] [Accepted: 04/06/2016] [Indexed: 02/07/2023]
Abstract
Charcot-Marie-Tooth disease type 4C (CMT4C) is one of the commonest autosomal recessive inherited peripheral neuropathies and is associated with mutations in the Rab11 effector, SH3TC2. Disruption of the SH3TC2-Rab11 interaction is the molecular abnormality underlying this disease. However, why SH3TC2 mutations cause an isolated demyelinating neuropathy remains unanswered. Here we show that SH3TC2 is an exclusive Schwann cell protein expressed late in myelination and is downregulated following denervation suggesting a functional role in myelin sheath maintenance. We support our data with an evolutionary cell biological analysis showing that the SH3TC2 gene, and its paralogue SH3TC1, are derived from an ancestral homologue, the duplication of which occurred in the common ancestor of jawed vertebrates, coincident with the appearance of Schwann cells and peripheral axon myelination. Furthermore, we report that SH3TC2 associates with integrin-α6, suggesting that aberrant Rab11-dependent endocytic trafficking of this critical laminin receptor in myelinated Schwann cells is connected to the demyelination seen in affected nerves. Our study therefore highlights the inherent evolutionary link between SH3TC2 and peripheral nerve myelination, pointing also towards a molecular mechanism underlying the specific demyelinating neuropathy that characterizes CMT4C.
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Affiliation(s)
- Sauparnika Vijay
- Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK
| | - Meagan Chiu
- Department of Cell Biology, University of Alberta, 5-31 Medical Science Building, Edmonton, Alberta, Canada
| | - Joel B Dacks
- Department of Cell Biology, University of Alberta, 5-31 Medical Science Building, Edmonton, Alberta, Canada
| | - Rhys C Roberts
- Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK.
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30
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Noseda R, Guerrero-Valero M, Alberizzi V, Previtali SC, Sherman DL, Palmisano M, Huganir RL, Nave KA, Cuenda A, Feltri ML, Brophy PJ, Bolino A. Kif13b Regulates PNS and CNS Myelination through the Dlg1 Scaffold. PLoS Biol 2016; 14:e1002440. [PMID: 27070899 PMCID: PMC4829179 DOI: 10.1371/journal.pbio.1002440] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 03/16/2016] [Indexed: 12/03/2022] Open
Abstract
Microtubule-based kinesin motors have many cellular functions, including the transport of a variety of cargos. However, unconventional roles have recently emerged, and kinesins have also been reported to act as scaffolding proteins and signaling molecules. In this work, we further extend the notion of unconventional functions for kinesin motor proteins, and we propose that Kif13b kinesin acts as a signaling molecule regulating peripheral nervous system (PNS) and central nervous system (CNS) myelination. In this process, positive and negative signals must be tightly coordinated in time and space to orchestrate myelin biogenesis. Here, we report that in Schwann cells Kif13b positively regulates myelination by promoting p38γ mitogen-activated protein kinase (MAPK)-mediated phosphorylation and ubiquitination of Discs large 1 (Dlg1), a known brake on myelination, which downregulates the phosphatidylinositol 3-kinase (PI3K)/v-AKT murine thymoma viral oncogene homolog (AKT) pathway. Interestingly, Kif13b also negatively regulates Dlg1 stability in oligodendrocytes, in which Dlg1, in contrast to Schwann cells, enhances AKT activation and promotes myelination. Thus, our data indicate that Kif13b is a negative regulator of CNS myelination. In summary, we propose a novel function for the Kif13b kinesin in glial cells as a key component of the PI3K/AKT signaling pathway, which controls myelination in both PNS and CNS. Kif13b is an unconventional kinesin that acts as a signaling molecule, regulating myelination via the Dlg1 scaffold in both Schwann cells (in the peripheral nervous system) and oligodendrocytes (in the central nervous system). Myelin is a multilayered extension of the Schwann and oligodendrocyte cell membranes, which wraps around neuronal axons to facilitate propagation of electric signals and to support axonal metabolism. However, the signals regulating myelin formation and how they are integrated and controlled to achieve homeostasis are still poorly understood. In Schwann cells, the Discs large 1 (Dlg1) protein is a known brake of myelination, which negatively regulates the amount of myelin produced so that myelin thickness is proportional to axonal diameter. In this paper, we report that in Schwann cells Dlg1 itself is tightly regulated to ensure proper myelination. We propose that Dlg1 function is further controlled by the Kif13b kinesin motor protein, which acts as a "brake of the brake" by downregulating Dlg1 activity. Surprisingly, we found that in oligodendrocytes Dlg1 is a positive and not a negative regulator of myelination. Thus, Kif13b-mediated negative regulation of Dlg1 ensures appropriate myelin production and thickness in the central nervous system. Our data further extend recently emerged unconventional roles for kinesins, which are usually implicated in cargo transport rather than in the modulation of signaling pathways. The elucidation of mechanisms regulating myelination may help to design specific approaches to favor re-myelination in demyelinating disorders in which this process is severely impaired.
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Affiliation(s)
- Roberta Noseda
- Division of Neuroscience, INSPE-Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
| | - Marta Guerrero-Valero
- Division of Neuroscience, INSPE-Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
| | - Valeria Alberizzi
- Division of Neuroscience, INSPE-Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
| | - Stefano C. Previtali
- Division of Neuroscience, INSPE-Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
- Department of Neurology, San Raffaele Scientific Institute, Milan, Italy
| | - Diane L. Sherman
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom
| | - Marilena Palmisano
- Hunter James Kelly Research Institute, Department of Biochemistry and Neurology, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, United States of America
| | - Richard L. Huganir
- The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Goettingen, Germany
| | - Ana Cuenda
- Department of Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Madrid, Spain
| | - Maria Laura Feltri
- Hunter James Kelly Research Institute, Department of Biochemistry and Neurology, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, United States of America
| | - Peter J. Brophy
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom
| | - Alessandra Bolino
- Division of Neuroscience, INSPE-Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
- * E-mail:
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Dobrowolny G, Bernardini C, Martini M, Baranzini M, Barba M, Musarò A. Muscle Expression of SOD1(G93A) Modulates microRNA and mRNA Transcription Pattern Associated with the Myelination Process in the Spinal Cord of Transgenic Mice. Front Cell Neurosci 2015; 9:463. [PMID: 26648847 PMCID: PMC4664730 DOI: 10.3389/fncel.2015.00463] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 11/13/2015] [Indexed: 12/14/2022] Open
Abstract
A crucial system severely affected in several neuromuscular diseases is the loss of effective connection between muscle and nerve, leading to a pathological non-communication between the two tissues. One of the best examples of impaired interplay between muscle and nerve is Amyotrophic Lateral Sclerosis, a neurodegenerative disease characterized by degeneration of motor neurons and muscle atrophy. Increasing evidences suggest that damage to motor neurons is enhanced by alterations in the neighboring non-neuronal cells and indicate that altered skeletal muscle might be the source of signals that impinge motor neuron activity and survival. Here we investigated whether muscle selective expression of SOD1G93A mutant gene modulates mRNAs and miRNAs expression at the level of spinal cord of MLC/SOD1G93A mice. Using a Taqman array, the Affymetrix Mouse Gene 2.0 ST approach and the MiRwalk 2.0 database, which provides information on miRNA and their predicted target genes, we revealed that muscle specific expression of SOD1G93A modulates relevant molecules of the genetic and epigenetic circuitry of myelin homeostasis in spinal cord of transgenic mice. Our study provides insights into the pathophysiological interplay between muscle and nerve and supports the hypothesis that muscle is a source of signals that can either positively or negatively affect the nervous system.
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Affiliation(s)
- Gabriella Dobrowolny
- DAHFMO-Unit of Histology and Medical Embryology, Institute Pasteur-Cenci Bolognetti, IIM, Sapienza University of Rome Rome, Italy ; Center for Life Nano Science at Sapienza, Istituto Italiano di Tecnologia Rome, Italy
| | - Camilla Bernardini
- Institute of Anatomy and Cell Biology, Università Cattolica del Sacro Cuore Rome, Italy
| | - Martina Martini
- DAHFMO-Unit of Histology and Medical Embryology, Institute Pasteur-Cenci Bolognetti, IIM, Sapienza University of Rome Rome, Italy ; Center for Life Nano Science at Sapienza, Istituto Italiano di Tecnologia Rome, Italy
| | - Mirko Baranzini
- Institute of Anatomy and Cell Biology, Università Cattolica del Sacro Cuore Rome, Italy
| | - Marta Barba
- Institute of Anatomy and Cell Biology, Università Cattolica del Sacro Cuore Rome, Italy
| | - Antonio Musarò
- DAHFMO-Unit of Histology and Medical Embryology, Institute Pasteur-Cenci Bolognetti, IIM, Sapienza University of Rome Rome, Italy ; Center for Life Nano Science at Sapienza, Istituto Italiano di Tecnologia Rome, Italy
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32
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Eckharter C, Junker N, Winter L, Fischer I, Fogli B, Kistner S, Pfaller K, Zheng B, Wiche G, Klimaschewski L, Schweigreiter R. Schwann Cell Expressed Nogo-B Modulates Axonal Branching of Adult Sensory Neurons Through the Nogo-B Receptor NgBR. Front Cell Neurosci 2015; 9:454. [PMID: 26635533 PMCID: PMC4655273 DOI: 10.3389/fncel.2015.00454] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 11/05/2015] [Indexed: 11/13/2022] Open
Abstract
In contrast to the central nervous system (CNS) nerve fibers do regenerate in the peripheral nervous system (PNS) although in a clinically unsatisfying manner. A major problem is excessive sprouting of regenerating axons which results in aberrant reinnervation of target tissue and impaired functional recovery. In the CNS, the reticulon protein Nogo-A has been identified as a prominent oligodendrocyte expressed inhibitor of long-distance growth of regenerating axons. We show here that the related isoform Nogo-B is abundantly expressed in Schwann cells in the PNS. Other than Nogo-A in oligodendrocytes, Nogo-B does not localize to the myelin sheath but is detected in the ER and the plasma membrane of Schwann cells. Adult sensory neurons that are cultured on nogo-a/b deficient Schwann cells form significantly fewer axonal branches vs. those on wildtype Schwann cells, while their maximal axonal extension is unaffected. We demonstrate that this effect of Nogo-B on neuronal morphology is restricted to undifferentiated Schwann cells and is mediated by direct physical contact between these two cell types. Moreover, we show that blocking the Nogo-B specific receptor NgBR, which we find expressed on sensory neurons and to interact with Schwann cell expressed Nogo-B, produces the same branching phenotype as observed after deletion of Nogo-B. These data provide evidence for a novel function of the nogo gene that is implemented by the Nogo-B isoform. The remarkably specific effects of Nogo-B/NgBR on axonal branching, while leaving axonal extension unaffected, are of potential clinical relevance in the context of excessive axonal sprouting after peripheral nerve injury.
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Affiliation(s)
- Christoph Eckharter
- Division of Neurobiochemistry, Biocenter, Innsbruck Medical University Innsbruck, Austria
| | - Nina Junker
- Division of Neurobiochemistry, Biocenter, Innsbruck Medical University Innsbruck, Austria
| | - Lilli Winter
- Max F. Perutz Laboratories, Department of Biochemistry and Cell Biology, University of Vienna Vienna, Austria
| | - Irmgard Fischer
- Max F. Perutz Laboratories, Department of Biochemistry and Cell Biology, University of Vienna Vienna, Austria
| | - Barbara Fogli
- Department of Anatomy, Histology and Embryology, Division of Neuroanatomy, Innsbruck Medical University Innsbruck, Austria
| | - Steffen Kistner
- Division of Neurobiochemistry, Biocenter, Innsbruck Medical University Innsbruck, Austria
| | - Kristian Pfaller
- Department of Anatomy, Histology and Embryology, Division of Histology and Embryology, Innsbruck Medical University Innsbruck, Austria
| | - Binhai Zheng
- Department of Neurosciences and Biomedical Sciences Graduate Program, School of Medicine, University of California, San Diego La Jolla, CA, USA
| | - Gerhard Wiche
- Max F. Perutz Laboratories, Department of Biochemistry and Cell Biology, University of Vienna Vienna, Austria
| | - Lars Klimaschewski
- Department of Anatomy, Histology and Embryology, Division of Neuroanatomy, Innsbruck Medical University Innsbruck, Austria
| | - Rüdiger Schweigreiter
- Division of Neurobiochemistry, Biocenter, Innsbruck Medical University Innsbruck, Austria
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33
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Brennan KM, Bai Y, Pisciotta C, Wang S, Feely SME, Hoegger M, Gutmann L, Moore SA, Gonzalez M, Sherman DL, Brophy PJ, Züchner S, Shy ME. Absence of Dystrophin Related Protein-2 disrupts Cajal bands in a patient with Charcot-Marie-Tooth disease. Neuromuscul Disord 2015; 25:786-93. [PMID: 26227883 PMCID: PMC4920059 DOI: 10.1016/j.nmd.2015.07.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 06/28/2015] [Accepted: 07/01/2015] [Indexed: 12/12/2022]
Abstract
Using exome sequencing in an individual with Charcot-Marie-Tooth disease (CMT) we have identified a mutation in the X-linked dystrophin-related protein 2 (DRP2) gene. A 60-year-old gentleman presented to our clinic and underwent clinical, electrophysiological and skin biopsy studies. The patient had clinical features of a length dependent sensorimotor neuropathy with an age of onset of 50 years. Neurophysiology revealed prolonged latencies with intermediate conduction velocities but no conduction block or temporal dispersion. A panel of 23 disease causing genes was sequenced and ultimately was uninformative. Whole exome sequencing revealed a stop mutation in DRP2, c.805C>T (Q269*). DRP2 interacts with periaxin and dystroglycan to form the periaxin-DRP2-dystroglycan complex which plays a role in the maintenance of the well-characterized Cajal bands of myelinating Schwann cells. Skin biopsies from our patient revealed a lack of DRP2 in myelinated dermal nerves by immunofluorescence. Furthermore electron microscopy failed to identify Cajal bands in the patient's dermal myelinated axons in keeping with ultrastructural pathology seen in the Drp2 knockout mouse. Both the electrophysiologic and dermal nerve twig pathology support the interpretation that this patient's DRP2 mutation causes characteristic morphological abnormalities recapitulating the Drp2 knockout model and potentially represents a novel genetic cause of CMT.
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Affiliation(s)
- Kathryn M Brennan
- Department of Neurology, University of Iowa, 200 Hawkins Drive, Iowa City, IA 52242, USA.
| | - Yunhong Bai
- Department of Neurology, University of Iowa, 200 Hawkins Drive, Iowa City, IA 52242, USA
| | - Chiara Pisciotta
- Department of Neurology, University of Iowa, 200 Hawkins Drive, Iowa City, IA 52242, USA
| | - Suola Wang
- Department of Neurology, University of Iowa, 200 Hawkins Drive, Iowa City, IA 52242, USA
| | - Shawna M E Feely
- Department of Neurology, University of Iowa, 200 Hawkins Drive, Iowa City, IA 52242, USA
| | - Mark Hoegger
- Department of Neurology, University of Iowa, 200 Hawkins Drive, Iowa City, IA 52242, USA
| | - Laurie Gutmann
- Department of Neurology, University of Iowa, 200 Hawkins Drive, Iowa City, IA 52242, USA
| | - Steven A Moore
- Department of Pathology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Michael Gonzalez
- Department of Human Genetics and Hussmann Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Diane L Sherman
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh EH16 4UU, UK
| | - Peter J Brophy
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh EH16 4UU, UK
| | - Stephan Züchner
- Department of Human Genetics and Hussmann Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Michael E Shy
- Department of Neurology, University of Iowa, 200 Hawkins Drive, Iowa City, IA 52242, USA
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34
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Abstract
Myelination of axons in the nervous system of vertebrates enables fast, saltatory impulse propagation, one of the best-understood concepts in neurophysiology. However, it took a long while to recognize the mechanistic complexity both of myelination by oligodendrocytes and Schwann cells and of their cellular interactions. In this review, we highlight recent advances in our understanding of myelin biogenesis, its lifelong plasticity, and the reciprocal interactions of myelinating glia with the axons they ensheath. In the central nervous system, myelination is also stimulated by axonal activity and astrocytes, whereas myelin clearance involves microglia/macrophages. Once myelinated, the long-term integrity of axons depends on glial supply of metabolites and neurotrophic factors. The relevance of this axoglial symbiosis is illustrated in normal brain aging and human myelin diseases, which can be studied in corresponding mouse models. Thus, myelinating cells serve a key role in preserving the connectivity and functions of a healthy nervous system.
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Affiliation(s)
- Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, D-37075 Göttingen, Germany; ,
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35
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Williams HJ, Hurst JR, Ocaka L, James C, Pao C, Chanudet E, Lescai F, Stanescu HC, Kleta R, Rosser E, Bacchelli C, Beales P. The use of whole-exome sequencing to disentangle complex phenotypes. Eur J Hum Genet 2015; 24:298-301. [PMID: 26059842 PMCID: PMC4717198 DOI: 10.1038/ejhg.2015.121] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 03/11/2015] [Accepted: 04/24/2015] [Indexed: 12/30/2022] Open
Abstract
The success of whole-exome sequencing to identify mutations causing single-gene disorders has been well documented. In contrast whole-exome sequencing has so far had limited success in the identification of variants causing more complex phenotypes that seem unlikely to be due to the disruption of a single gene. We describe a family where two male offspring of healthy first cousin parents present a complex phenotype consisting of peripheral neuropathy and bronchiectasis that has not been described previously in the literature. Due to the fact that both children had the same problems in the context of parental consanguinity we hypothesised illness resulted from either X-linked or autosomal recessive inheritance. Through the use of whole-exome sequencing we were able to simplify this complex phenotype and identified a causative mutation (p.R1070*) in the gene periaxin (PRX), a gene previously shown to cause peripheral neuropathy (Dejerine-Sottas syndrome) when this mutation is present. For the bronchiectasis phenotype we were unable to identify a causal single mutation or compound heterozygote, reflecting the heterogeneous nature of this phenotype. In conclusion, in this study we show that whole-exome sequencing has the power to disentangle complex phenotypes through the identification of causative genetic mutations for distinct clinical disorders that were previously masked.
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Affiliation(s)
- Hywel J Williams
- Centre for Translational Omics - GOSgene, UCL Institute of Child Health, University College London, London, UK
| | - John R Hurst
- UCL Respiratory Medicine, UCL Medical School, London, UK
| | - Louise Ocaka
- Centre for Translational Omics - GOSgene, UCL Institute of Child Health, University College London, London, UK
| | - Chela James
- Centre for Translational Omics - GOSgene, UCL Institute of Child Health, University College London, London, UK
| | - Caroline Pao
- Paediatric Respiratory Medicine, Royal London Hospital, Whitechapel, London, UK
| | - Estelle Chanudet
- Centre for Translational Omics - GOSgene, UCL Institute of Child Health, University College London, London, UK
| | - Francesco Lescai
- Centre for Translational Omics - GOSgene, UCL Institute of Child Health, University College London, London, UK
| | | | - Robert Kleta
- Centre for Translational Omics - GOSgene, UCL Institute of Child Health, University College London, London, UK.,UCL Respiratory Medicine, UCL Medical School, London, UK
| | | | - Elisabeth Rosser
- Department of Clinical Genetics, Great Ormond St Hospital, London, UK
| | - Chiara Bacchelli
- Centre for Translational Omics - GOSgene, UCL Institute of Child Health, University College London, London, UK
| | - Philip Beales
- Centre for Translational Omics - GOSgene, UCL Institute of Child Health, University College London, London, UK
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Abstract
Myelinated nerve fibers are essential for the rapid propagation of action potentials by saltatory conduction. They form as the result of reciprocal interactions between axons and Schwann cells. Extrinsic signals from the axon, and the extracellular matrix, drive Schwann cells to adopt a myelinating fate, whereas myelination reorganizes the axon for its role in conduction and is essential for its integrity. Here, we review our current understanding of the development, molecular organization, and function of myelinating Schwann cells. Recent findings into the extrinsic signals that drive Schwann cell myelination, their cognate receptors, and the downstream intracellular signaling pathways they activate will be described. Together, these studies provide important new insights into how these pathways converge to activate the transcriptional cascade of myelination and remodel the actin cytoskeleton that is critical for morphogenesis of the myelin sheath.
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Affiliation(s)
- James L Salzer
- Department of Neuroscience and Physiology, New York University Neuroscience Institute, New York University School of Medicine, New York, New York 10016
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37
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Demyelinating CMT–what’s known, what’s new and what’s in store? Neurosci Lett 2015; 596:14-26. [DOI: 10.1016/j.neulet.2015.01.059] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 01/23/2015] [Indexed: 02/06/2023]
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38
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Hung HA, Sun G, Keles S, Svaren J. Dynamic regulation of Schwann cell enhancers after peripheral nerve injury. J Biol Chem 2015; 290:6937-50. [PMID: 25614629 PMCID: PMC4358118 DOI: 10.1074/jbc.m114.622878] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 12/31/2014] [Indexed: 12/20/2022] Open
Abstract
Myelination of the peripheral nervous system is required for axonal function and long term stability. After peripheral nerve injury, Schwann cells transition from axon myelination to a demyelinated state that supports neuronal survival and ultimately remyelination of axons. Reprogramming of gene expression patterns during development and injury responses is shaped by the actions of distal regulatory elements that integrate the actions of multiple transcription factors. We used ChIP-seq to measure changes in histone H3K27 acetylation, a mark of active enhancers, to identify enhancers in myelinating rat peripheral nerve and their dynamics after demyelinating nerve injury. Analysis of injury-induced enhancers identified enriched motifs for c-Jun, a transcription factor required for Schwann cells to support nerve regeneration. We identify a c-Jun-bound enhancer in the gene for Runx2, a transcription factor induced after nerve injury, and we show that Runx2 is required for activation of other induced genes. In contrast, enhancers that lose H3K27ac after nerve injury are enriched for binding sites of the Sox10 and early growth response 2 (Egr2/Krox20) transcription factors, which are critical determinants of Schwann cell differentiation. Egr2 expression is lost after nerve injury, and many Egr2-binding sites lose H3K27ac after nerve injury. However, the majority of Egr2-bound enhancers retain H3K27ac, indicating that other transcription factors maintain active enhancer status after nerve injury. The global epigenomic changes in H3K27ac deposition pinpoint dynamic changes in enhancers that mediate the effects of transcription factors that control Schwann cell myelination and peripheral nervous system responses to nerve injury.
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Affiliation(s)
- Holly A Hung
- From the Waisman Center, Cellular and Molecular Pathology Graduate Program, and
| | - Guannan Sun
- Departments of Biostatistics and Medical Informatics and
| | - Sunduz Keles
- Departments of Biostatistics and Medical Informatics and
| | - John Svaren
- From the Waisman Center, Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin 53705
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39
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FAK is required for Schwann cell spreading on immature basal lamina to coordinate the radial sorting of peripheral axons with myelination. J Neurosci 2015; 34:13422-34. [PMID: 25274820 DOI: 10.1523/jneurosci.1764-14.2014] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Without Focal Adhesion Kinase (FAK), developing murine Schwann cells (SCs) proliferate poorly, sort axons inefficiently, and cannot myelinate peripheral nerves. Here we show that FAK is required for the development of SCs when their basal lamina (BL) is fragmentary, but not when it is mature in vivo. Mutant SCs fail to spread on fragmentary BL during development in vivo, and this is phenocopied by SCs lacking functional FAK on low laminin (LN) in vitro. Furthermore, SCs without functional FAK initiate differentiation prematurely, both in vivo and in vitro. In contrast to their behavior on high levels of LN, SCs lacking functional FAK grown on low LN display reduced spreading, proliferation, and indicators of contractility (i.e., stress fibers, arcs, and focal adhesions) and are primed to differentiate. Growth of SCs lacking functional FAK on increasing LN concentrations in vitro revealed that differentiation is not regulated by G1 arrest but rather by cell spreading and the level of contractile actomyosin. The importance of FAK as a critical regulator of the specific response of developing SCs to fragmentary BL was supported by the ability of adult FAK mutant SCs to remyelinate demyelinated adult nerves on mature BL in vivo. We conclude that FAK promotes the spreading and actomyosin contractility of immature SCs on fragmentary BL, thus maintaining their proliferation, and preventing differentiation until they reach high density, thereby promoting radial sorting. Hence, FAK has a critical role in the response of SCs to limiting BL by promoting proliferation and preventing premature SC differentiation.
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Yang Y, Shi Y. Retracted Article: Spectrin-like domain 2 of DRP2 serves as a novel binding region for the NLS2 and 3 sub-domains of L-periaxin. RSC Adv 2015. [DOI: 10.1039/c5ra12703c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The NLS1 domain of L-periaxin involved in nucleo-cytoplasmic shuttling, NLS2 and 3 participated in interaction with spectrin-like domain 2 of DRP2. The binding model of DRP2 and L-periaxin is crucial for understanding the role of L-periaxin in PNS.
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Affiliation(s)
- Yan Yang
- Key Laboratory of Chemical Biology and Molecular Engineering of the Ministry of Education
- Institute of Biotechnology
- Shanxi University
- Taiyuan 030006
- China
| | - YaWei Shi
- Key Laboratory of Chemical Biology and Molecular Engineering of the Ministry of Education
- Institute of Biotechnology
- Shanxi University
- Taiyuan 030006
- China
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Exome sequencing in multiplex autism families suggests a major role for heterozygous truncating mutations. Mol Psychiatry 2014; 19:784-90. [PMID: 23999528 DOI: 10.1038/mp.2013.106] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 05/23/2013] [Accepted: 07/22/2013] [Indexed: 12/21/2022]
Abstract
Autism is a severe neurodevelopmental disorder, the aetiology of which remains mainly unknown. Family and twin studies provide strong evidence that genetic factors have a major role in the aetiology of this disease. Recently, whole exome sequencing (WES) efforts have focused mainly on rare de novo variants in singleton families. Although these studies have provided pioneering insights, de novo variants probably explain only a small proportion of the autism risk variance. In this study, we performed exome sequencing of 10 autism multiplex families with the aim of investigating the role of rare variants that are coinherited in the affected sibs. The pool of variants selected in our study is enriched with genes involved in neuronal functions or previously reported in psychiatric disorders, as shown by Gene Ontology analysis and by browsing the Neurocarta database. Our data suggest that rare truncating heterozygous variants have a predominant role in the aetiology of autism. Using a multiple linear regression model, we found that the burden of truncating mutations correlates with a lower non-verbal intelligence quotient (NVIQ). Also, the number of truncating mutations that were transmitted to the affected sibs was significantly higher (twofold) than those not transmitted. Protein-protein interaction analysis performed with our list of mutated genes revealed that the postsynaptic YWHAZ is the most interconnected node of the network. Among the genes found disrupted in our study, there is evidence suggesting that YWHAZ and also the X-linked DRP2 may be considered as novel autism candidate genes.
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von Boxberg Y, Soares S, Féréol S, Fodil R, Bartolami S, Taxi J, Tricaud N, Nothias F. Giant scaffolding protein AHNAK1 interacts with β-dystroglycan and controls motility and mechanical properties of Schwann cells. Glia 2014; 62:1392-406. [PMID: 24796807 DOI: 10.1002/glia.22685] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 04/11/2014] [Accepted: 04/17/2014] [Indexed: 01/02/2023]
Abstract
The profound morphofunctional changes that Schwann cells (SCs) undergo during their migration and elongation on axons, as well as during axon sorting, ensheathment, and myelination, require their close interaction with the surrounding laminin-rich basal lamina. In contrast to myelinating central nervous system glia, SCs strongly and constitutively express the giant scaffolding protein AHNAK1, localized essentially underneath the outer, abaxonal plasma membrane. Using electron microscopy, we show here that in the sciatic nerve of ahnak1(-) (/) (-) mice the ultrastructure of myelinated, and unmyelinated (Remak) fibers is affected. The major SC laminin receptor β-dystroglycan co-immunoprecipitates with AHNAK1 shows reduced expression in ahnak1(-) (/) (-) SCs, and is no longer detectable in Cajal bands on myelinated fibers in ahnak1(-) (/) (-) sciatic nerve. Reduced migration velocity in a scratch wound assay of purified ahnak1(-) (/) (-) primary SCs cultured on a laminin substrate indicated a function of AHNAK1 in SC motility. This was corroborated by atomic force microscopy measurements, which revealed a greater mechanical rigidity of shaft and leading tip of ahnak1(-) (/) (-) SC processes. Internodal lengths of large fibers are decreased in ahnak1(-) (/) (-) sciatic nerve, and longitudinal extension of myelin segments is even more strongly reduced after acute knockdown of AHNAK1 in SCs of developing sciatic nerve. Together, our results suggest that by interfering in the cross-talk between the transmembrane form of the laminin receptor dystroglycan and F-actin, AHNAK1 influences the cytoskeleton organization of SCs, and thus plays a role in the regulation of their morphology and motility and lastly, the myelination process.
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Affiliation(s)
- Ysander von Boxberg
- Sorbonne Universités, UPMC CR18 (NPS), Paris, France; Neuroscience Paris Seine (NPS), CNRS UMR 8246, Paris, France; Neuroscience Paris Seine (NPS), INSERM U1130, Paris, France
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da Silva TF, Eira J, Lopes AT, Malheiro AR, Sousa V, Luoma A, Avila RL, Wanders RJA, Just WW, Kirschner DA, Sousa MM, Brites P. Peripheral nervous system plasmalogens regulate Schwann cell differentiation and myelination. J Clin Invest 2014; 124:2560-70. [PMID: 24762439 DOI: 10.1172/jci72063] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Rhizomelic chondrodysplasia punctata (RCDP) is a developmental disorder characterized by hypotonia, cataracts, abnormal ossification, impaired motor development, and intellectual disability. The underlying etiology of RCDP is a deficiency in the biosynthesis of ether phospholipids, of which plasmalogens are the most abundant form in nervous tissue and myelin; however, the role of plasmalogens in the peripheral nervous system is poorly defined. Here, we used mouse models of RCDP and analyzed the consequence of plasmalogen deficiency in peripheral nerves. We determined that plasmalogens are crucial for Schwann cell development and differentiation and that plasmalogen defects impaired radial sorting, myelination, and myelin structure. Plasmalogen insufficiency resulted in defective protein kinase B (AKT) phosphorylation and subsequent signaling, causing overt activation of glycogen synthase kinase 3β (GSK3β) in nerves of mutant mice. Treatment with GSK3β inhibitors, lithium, or 4-benzyl-2-methyl-1,2,4-thiadiazolidine-3,5-dione (TDZD-8) restored Schwann cell defects, effectively bypassing plasmalogen deficiency. Our results demonstrate the requirement of plasmalogens for the correct and timely differentiation of Schwann cells and for the process of myelination. In addition, these studies identify a mechanism by which the lack of a membrane phospholipid causes neuropathology, implicating plasmalogens as regulators of membrane and cell signaling.
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Nuclear export of L-periaxin, mediated by its nuclear export signal in the PDZ domain. PLoS One 2014; 9:e91953. [PMID: 24633211 PMCID: PMC3954830 DOI: 10.1371/journal.pone.0091953] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 02/18/2014] [Indexed: 11/30/2022] Open
Abstract
Myelinating Schwann cells specifically express L-periaxin (L-PRX) in the mammalian peripheral nervous system. Several loss-of-function mutations in periaxin have been described and linked to autosomal recessive Dejerine Sottas neuropathy and to demyelinating Charcot-Marie-Tooth disease. The localization of L-periaxin is developmentally regulated in the nucleus and the plasma membrane of Schwann cells. In this study, L-periaxin, which contains a PDZ domain, a nuclear localization signal (NLS) domain, a repeat domain, and an acidic domain, was localized in the cytoplasm of RSC96 cells. By contrast, a mutant L-periaxin with a deleted PDZ domain was localized mainly in the nucleus of RSC96 cells. After a nuclear cyclin A1, which is localized exclusively in the nucleus, was fused with the PDZ domain, cyclinA1was found in the cytoplasm of RSC96 cells. Treatment with leptomycin B (LMB), a specific inhibitor of nuclear export mediated by leucine-rich nuclear export signal (NES), also causes nuclear accumulation of wild-type L-periaxin. Double leucine mutation (L83, 85Q) in the putative NES in the PDZ domain prevented L-periaxin nuclear export and induced nuclear accumulation. These results suggested that the localization of L-periaxin in the cytoplasm is supported by NES in the PDZ domain.
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Walko G, Wögenstein KL, Winter L, Fischer I, Feltri ML, Wiche G. Stabilization of the dystroglycan complex in Cajal bands of myelinating Schwann cells through plectin-mediated anchorage to vimentin filaments. Glia 2013; 61:1274-87. [PMID: 23836526 DOI: 10.1002/glia.22514] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2012] [Accepted: 03/28/2013] [Indexed: 11/06/2022]
Abstract
Previous studies have unmasked plectin, a uniquely versatile intermediate filament-associated cytolinker protein, to be essential for skin and skeletal muscle integrity. Different sets of isoforms of the protein were found to stabilize cells mechanically, regulate cytoskeletal dynamics, and serve as a scaffolding platform for signaling molecules. Here, we investigated whether a similar scenario prevails in myelinating Schwann cells. Using isoform-specific antibodies, the two plectin variants predominantly expressed in the cytoplasmic compartment (Cajal bands) of Schwann cells were identified as plectin (P)1 and P1c. Coimmunoprecipitation and immunolocalization experiments revealed complex formation of Cajal band plectin with β-dystroglycan, the core component of the dystrophin glycoprotein complex that in Schwann cells is crucial for the compartmentalization and stabilization of the myelin sheath. To study the functional implications of Schwann cell-specific plectin-β-dystroglycan interaction, we generated conditional (Schwann cell-restricted) plectin knockout mice. Ablation of plectin in myelinating Schwann cells (SCs) was found not to affect myelin sheath formation but to abrogate the tight association of the dystroglycan complex with the intermediate filament cytoskeleton. We show that the disruption of this association leads to the destabilization of the dystroglycan complex combined with increased myelin sheath deformations observed in the peripheral nerve during ageing of the animal.
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Affiliation(s)
- Gernot Walko
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna, Vienna, Austria
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Han H, Myllykoski M, Ruskamo S, Wang C, Kursula P. Myelin-specific proteins: a structurally diverse group of membrane-interacting molecules. Biofactors 2013; 39:233-41. [PMID: 23780694 DOI: 10.1002/biof.1076] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 11/15/2012] [Indexed: 12/15/2022]
Abstract
The myelin sheath is a multilayered membrane in the nervous system, which has unique biochemical properties. Myelin carries a set of specific high-abundance proteins, the structure and function of which are still poorly understood. The proteins of the myelin sheath are involved in a number of neurological diseases, including autoimmune diseases and inherited neuropathies. In this review, we briefly discuss the structural properties and functions of selected myelin-specific proteins (P0, myelin oligodendrocyte glycoprotein, myelin-associated glycoprotein, myelin basic protein, myelin-associated oligodendrocytic basic protein, P2, proteolipid protein, peripheral myelin protein of 22 kDa, 2',3'-cyclic nucleotide 3'-phosphodiesterase, and periaxin); such properties include, for example, interactions with lipid bilayers and the presence of large intrinsically disordered regions in some myelin proteins. A detailed understanding of myelin protein structure and function at the molecular level will be required to fully grasp their physiological roles in the myelin sheath.
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Affiliation(s)
- Huijong Han
- Department of Biochemistry and Biocenter Oulu, University of Oulu, Oulu, Finland
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Wu L, Williams A, Delaney A, Sherman D, Brophy P. Increasing internodal distance in myelinated nerves accelerates nerve conduction to a flat maximum. Curr Biol 2012; 22:1957-61. [PMID: 23022068 PMCID: PMC3482659 DOI: 10.1016/j.cub.2012.08.025] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 08/09/2012] [Accepted: 08/14/2012] [Indexed: 11/17/2022]
Abstract
Predictions that conduction velocities are sensitive to the distance between nodes of Ranvier in myelinated axons have implications for nervous system function during growth and repair. Internodal lengths defined by Schwann cells in hindlimb nerves, for example, can undergo a 4-fold increase during mouse development, and regenerated nerves have internodes that are uniformly short. Nevertheless, the influence of internodal length on conduction speed has limited experimental support. Here, we examined this problem in mice expressing a mutant version of periaxin, a protein required for Schwann cell elongation. Importantly, elongation of mutant Schwann cells was retarded without significant derangements to myelination or axon caliber. In young mice with short mutant Schwann cells, nerve conduction velocity was reduced and motor function was impaired. This demonstrates a functional relationship between internodal distance and conduction speed. Moreover, as internodes lengthened during postnatal growth, conduction velocities recovered to normal values and mutant mice exhibited normal motor and sensory behavior. This restoration of function confirms a further prediction by Huxley and Stämpfli that conduction speeds should increase as internodal distances lengthen until a "flat maximum" is reached, beyond which no further gains in conduction velocity accrue.
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Affiliation(s)
- Lai Man N. Wu
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Anna Williams
- MRC Centre for Regenerative Medicine and Centre for Multiple Sclerosis Research, University of Edinburgh, Edinburgh EH16 4UU, UK
| | - Ada Delaney
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Diane L. Sherman
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Peter J. Brophy
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh EH16 4SB, UK
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