1
|
Jacquier A, Risson V, Simonet T, Roussange F, Lacoste N, Ribault S, Carras J, Theuriet J, Girard E, Grosjean I, Le Goff L, Kröger S, Meltoranta J, Bauché S, Sternberg D, Fournier E, Kostera-Pruszczyk A, O’Connor E, Eymard B, Lochmüller H, Martinat C, Schaeffer L. Severe congenital myasthenic syndromes caused by agrin mutations affecting secretion by motoneurons. Acta Neuropathol 2022; 144:707-731. [PMID: 35948834 PMCID: PMC9468088 DOI: 10.1007/s00401-022-02475-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 07/25/2022] [Accepted: 07/25/2022] [Indexed: 01/28/2023]
Abstract
Congenital myasthenic syndromes (CMS) are predominantly characterized by muscle weakness and fatigability and can be caused by a variety of mutations in genes required for neuromuscular junction formation and maintenance. Among them, AGRN encodes agrin, an essential synaptic protein secreted by motoneurons. We have identified severe CMS patients with uncharacterized p.R1671Q, p.R1698P and p.L1664P mutations in the LG2 domain of agrin. Overexpression in primary motoneurons cultures in vitro and in chick spinal motoneurons in vivo revealed that the mutations modified agrin trafficking, leading to its accumulation in the soma and/or in the axon. Expression of mutant agrins in cultured cells demonstrated accumulation of agrin in the endoplasmic reticulum associated with induction of unfolded protein response (UPR) and impaired secretion in the culture medium. Interestingly, evaluation of the specific activity of individual agrins on AChR cluster formation indicated that when secreted, mutant agrins retained a normal capacity to trigger the formation of AChR clusters. To confirm agrin accumulation and secretion defect, iPS cells were derived from a patient and differentiated into motoneurons. Patient iPS-derived motoneurons accumulated mutant agrin in the soma and increased XBP1 mRNA splicing, suggesting UPR activation. Moreover, co-cultures of patient iPS-derived motoneurons with myotubes confirmed the deficit in agrin secretion and revealed a reduction in motoneuron survival. Altogether, we report the first mutations in AGRN gene that specifically affect agrin secretion by motoneurons. Interestingly, the three patients carrying these mutations were initially suspected of spinal muscular atrophy (SMA). Therefore, in the presence of patients with a clinical presentation of SMA but without mutation in the SMN1 gene, it can be worth to look for mutations in AGRN.
Collapse
Affiliation(s)
- Arnaud Jacquier
- Pathophysiology and Genetics of Neuron and Muscle, Faculté de Médecine Lyon Est, CNRS UMR 5261, INSERM U1315, Université Lyon1, Lyon, France ,grid.413852.90000 0001 2163 3825Hospices Civils de Lyon, Groupement Est, Bron, France
| | - Valérie Risson
- Pathophysiology and Genetics of Neuron and Muscle, Faculté de Médecine Lyon Est, CNRS UMR 5261, INSERM U1315, Université Lyon1, Lyon, France
| | - Thomas Simonet
- Pathophysiology and Genetics of Neuron and Muscle, Faculté de Médecine Lyon Est, CNRS UMR 5261, INSERM U1315, Université Lyon1, Lyon, France ,grid.413852.90000 0001 2163 3825Hospices Civils de Lyon, Groupement Est, Bron, France
| | - Florine Roussange
- grid.503216.30000 0004 0618 2124INSERM/UEPS UMR 861, Paris Saclay Université, I-STEM, 91100 Corbeil-Essonnes, France
| | - Nicolas Lacoste
- Pathophysiology and Genetics of Neuron and Muscle, Faculté de Médecine Lyon Est, CNRS UMR 5261, INSERM U1315, Université Lyon1, Lyon, France
| | - Shams Ribault
- Pathophysiology and Genetics of Neuron and Muscle, Faculté de Médecine Lyon Est, CNRS UMR 5261, INSERM U1315, Université Lyon1, Lyon, France ,grid.413852.90000 0001 2163 3825Service de Médecine Physique et de Réadaptation, Hôpital Henry Gabrielle, Hospices Civils de Lyon, 69230 Saint-Genis-Laval, France
| | - Julien Carras
- Pathophysiology and Genetics of Neuron and Muscle, Faculté de Médecine Lyon Est, CNRS UMR 5261, INSERM U1315, Université Lyon1, Lyon, France ,grid.413852.90000 0001 2163 3825Hospices Civils de Lyon, Groupement Est, Bron, France
| | - Julian Theuriet
- Pathophysiology and Genetics of Neuron and Muscle, Faculté de Médecine Lyon Est, CNRS UMR 5261, INSERM U1315, Université Lyon1, Lyon, France ,grid.413852.90000 0001 2163 3825Hospices Civils de Lyon, Groupement Est, Bron, France
| | - Emmanuelle Girard
- Pathophysiology and Genetics of Neuron and Muscle, Faculté de Médecine Lyon Est, CNRS UMR 5261, INSERM U1315, Université Lyon1, Lyon, France
| | - Isabelle Grosjean
- Pathophysiology and Genetics of Neuron and Muscle, Faculté de Médecine Lyon Est, CNRS UMR 5261, INSERM U1315, Université Lyon1, Lyon, France
| | - Laure Le Goff
- grid.413852.90000 0001 2163 3825Hospices Civils de Lyon, Groupement Est, Bron, France
| | - Stephan Kröger
- Department of Physiological Genomics, Biomedical Center, Planegg, Martinsried, Germany
| | - Julia Meltoranta
- Department of Physiological Genomics, Biomedical Center, Planegg, Martinsried, Germany
| | - Stéphanie Bauché
- grid.462844.80000 0001 2308 1657Inserm U 1127, CNRS UMR 7225, UPMC Université Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle Épinière, ICM, Sorbonne Universités, 75013 Paris, France
| | - Damien Sternberg
- grid.462844.80000 0001 2308 1657Inserm U 1127, CNRS UMR 7225, UPMC Université Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle Épinière, ICM, Sorbonne Universités, 75013 Paris, France ,grid.411439.a0000 0001 2150 9058APHP, UF Cardiogénétique et Myogénétique, Service de Biochimie Métabolique, Groupe Hospitalier Pitié-Salpêtrière, Paris, France
| | - Emmanuel Fournier
- grid.462844.80000 0001 2308 1657Inserm U 1127, CNRS UMR 7225, UPMC Université Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle Épinière, ICM, Sorbonne Universités, 75013 Paris, France ,grid.411439.a0000 0001 2150 9058AP-HP, Hôpital Pitié-Salpêtrière, 75013 Paris, France ,grid.462844.80000 0001 2308 1657Département d’Éthique de l’Université et des enseignements de Physiologie de la Faculté de Médecine Pitié-Salpêtrière, 75013 Paris, France
| | - Anna Kostera-Pruszczyk
- grid.13339.3b0000000113287408Department of Neurology, Medical University of Warsaw, Warsaw, Poland
| | - Emily O’Connor
- grid.28046.380000 0001 2182 2255Division of Neurology, Department of Medicine, Children’s Hospital of Eastern Ontario Research Institute, The Ottawa Hospital and Brain and Mind Research Institute, University of Ottawa, Ottawa, Canada
| | - Bruno Eymard
- grid.462844.80000 0001 2308 1657Inserm U 1127, CNRS UMR 7225, UPMC Université Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle Épinière, ICM, Sorbonne Universités, 75013 Paris, France ,grid.411439.a0000 0001 2150 9058AP-HP, Hôpital Pitié-Salpêtrière, 75013 Paris, France
| | - Hanns Lochmüller
- grid.28046.380000 0001 2182 2255Division of Neurology, Department of Medicine, Children’s Hospital of Eastern Ontario Research Institute, The Ottawa Hospital and Brain and Mind Research Institute, University of Ottawa, Ottawa, Canada
| | - Cécile Martinat
- grid.503216.30000 0004 0618 2124INSERM/UEPS UMR 861, Paris Saclay Université, I-STEM, 91100 Corbeil-Essonnes, France
| | - Laurent Schaeffer
- Pathophysiology and Genetics of Neuron and Muscle, Faculté de Médecine Lyon Est, CNRS UMR 5261, INSERM U1315, Université Lyon1, Lyon, France ,grid.413852.90000 0001 2163 3825Hospices Civils de Lyon, Groupement Est, Bron, France
| |
Collapse
|