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Roos A, Schmitt LI, Hansmann C, Hezel S, Salmanian S, Hentschel A, Meyer N, Marina AD, Kölbel H, Kleinschnitz C, Schara-Schmidt U, Leo M, Hagenacker T. Alteration of LARGE1 abundance in patients and a mouse model of 5q-associated spinal muscular atrophy. Acta Neuropathol 2024; 147:53. [PMID: 38470509 PMCID: PMC10933199 DOI: 10.1007/s00401-024-02709-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 02/16/2024] [Accepted: 02/16/2024] [Indexed: 03/14/2024]
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disorder caused by recessive pathogenic variants affecting the survival of motor neuron (SMN1) gene (localized on 5q). In consequence, cells lack expression of the corresponding protein. This pathophysiological condition is clinically associated with motor neuron (MN) degeneration leading to severe muscular atrophy. Additionally, vulnerability of other cellular populations and tissues including skeletal muscle has been demonstrated. Although the therapeutic options for SMA have considerably changed, treatment responses may differ thus underlining the persistent need for validated biomarkers. To address this need and to identify novel marker proteins for SMA, we performed unbiased proteomic profiling on cerebrospinal fluid derived (CSF) from genetically proven SMA type 1-3 cases and afterwards performed ELISA studies on CSF and serum samples to validate the potential of a novel biomarker candidates in both body fluids. To further decipher the pathophysiological impact of this biomarker, immunofluorescence studies were carried out on spinal cord and skeletal muscle derived from a 5q-SMA mouse model. Proteomics revealed increase of LARGE1 in CSF derived from adult patients showing a clinical response upon treatment with nusinersen. Moreover, LARGE1 levels were validated in CSF samples of further SMA patients (type 1-3) by ELISA. These studies also unveiled a distinguishment between groups in improvement of motor skills: adult patients do present with lowered level per se at baseline visit while no elevation upon treatment in the pediatric cohort can be observed. ELISA-based studies of serum samples showed no changes in the pediatric cohort but unraveled elevated level in adult patients responding to future intervention with nusinersen, while non-responders did not show a significant increase. Additional immunofluorescence studies of LARGE1 in MN and skeletal muscle of a SMA type 3 mouse model revealed an increase of LARGE1 during disease progression. Our combined data unraveled LARGE1 as a protein dysregulated in serum and CSF of SMA-patients (and in MN and skeletal muscle of SMA mice) holding the potential to serve as a disease marker for SMA and enabling to differentiate between patients responding and non-responding to therapy with nusinersen.
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Affiliation(s)
- Andreas Roos
- Department of Pediatric Neurology, Center for Neuromuscular Disorders, Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147, Essen, Germany
- Division of Neurology, Department of Medicine, The Ottawa Hospital, Brain and Mind Research Institute and Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
| | - Linda-Isabell Schmitt
- Department of Neurology, Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147, Essen, Germany.
| | - Christina Hansmann
- Department of Neurology, Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Stefanie Hezel
- Department of Neurology, Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Schahin Salmanian
- Department of Neurology, Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Andreas Hentschel
- Leibniz-Institut Für Analytische Wissenschaften-ISAS-e.V., Dortmund, Germany, Otto-Hahn-Strasse 6B, 44227, Dortmund, Germany
| | - Nancy Meyer
- Department of Pediatric Neurology, Center for Neuromuscular Disorders, Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Adela Della Marina
- Department of Pediatric Neurology, Center for Neuromuscular Disorders, Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Heike Kölbel
- Department of Pediatric Neurology, Center for Neuromuscular Disorders, Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Christoph Kleinschnitz
- Department of Neurology, Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Ulrike Schara-Schmidt
- Department of Pediatric Neurology, Center for Neuromuscular Disorders, Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Markus Leo
- Department of Neurology, Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Tim Hagenacker
- Department of Neurology, Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147, Essen, Germany
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Spinal astrocyte dysfunction drives motor neuron loss in late-onset spinal muscular atrophy. Acta Neuropathol 2023; 145:611-635. [PMID: 36930296 PMCID: PMC10119066 DOI: 10.1007/s00401-023-02554-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 03/01/2023] [Accepted: 03/01/2023] [Indexed: 03/18/2023]
Abstract
Spinal muscular atrophy (SMA) is a progressive neuromuscular disorder caused by a loss of the survival of motor neuron 1 (SMN1) gene, resulting in a loss of spinal motor neurons (MNs), leading to muscle weakness and wasting. The pathogenesis of MN loss in SMA and the selective vulnerability in different cellular populations are not fully understood. To investigate the role of spinal astrocytes in the pathogenesis of late-onset SMA, we used a mouse model in addition to in vitro approaches. Immunostaining, Western blot analysis, small interfering ribonucleic acid (siRNA) transfections, functional assays, enzyme-linked immunosorbent assay (ELISA), behavioral tests, and electrophysiological measurements were performed. Early activation of spinal astrocytes and a reduction of the excitatory amino acid transporter 1 (EAAT1) on postnatal day (P) 20 preceded the loss of spinal MNs in SMA mice occurring on P42. EAAT1 reduction resulted in elevated glutamate levels in the spinal cord of SMA mice at P20 and P42. SMA-like astrocytes generated by siRNA and an ex vivo model of glutamate excitotoxicity involving organotypic spinal cord slice cultures revealed the critical role of glutamate homeostasis in the degeneration of MNs. The pre-emptive administration of arundic acid (AA), as an inhibitor of astrocyte activation, to SMA mice prior to the loss of motor neurons (P28) resulted in elevated EAAT1 protein levels compared to vehicle-treated SMA mice and prevented the increase of glutamate in the spinal cord and the loss of spinal MNs. Furthermore, AA preserved motor functions during behavioral experiments, the electrophysiological properties, and muscle alteration of SMA mice. In a translational approach, we transfected healthy human fibroblasts with SMN1 siRNA, resulting in reduced EAAT1 expression and reduced uptake but increased glutamate release. These findings were verified by detecting elevated glutamate levels and reduced levels of EAAT1 in cerebrospinal fluid of untreated SMA type 2 and 3 patients. In addition, glutamate was elevated in serum samples, while EAAT1 was not detectable. Our data give evidence for the crucial role of spinal astrocytes in the pathogenesis of late-onset SMA, a potential driving force for MN loss by glutamate excitotoxicity caused by EAAT1 reduction as an early pathophysiological event. Furthermore, our study introduces EAAT1 as a potential therapeutic target for additional SMN-independent therapy strategies to complement SMN-enhancing drugs.
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Freigang M, Steinacker P, Wurster CD, Schreiber-Katz O, Osmanovic A, Petri S, Koch JC, Rostásy K, Huss A, Tumani H, Winter B, Falkenburger B, Ludolph AC, Otto M, Hermann A, Günther R. Glial fibrillary acidic protein in cerebrospinal fluid of patients with spinal muscular atrophy. Ann Clin Transl Neurol 2022; 9:1437-1448. [PMID: 35951535 PMCID: PMC9463944 DOI: 10.1002/acn3.51645] [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: 03/08/2022] [Revised: 07/22/2022] [Accepted: 07/23/2022] [Indexed: 11/29/2022] Open
Abstract
Objective Activated astroglia is involved in the pathophysiology of neurodegenerative diseases and has also been described in animal models of spinal muscular atrophy (SMA). Given the urgent need of biomarkers for treatment monitoring of new RNA‐modifying and gene replacement therapies in SMA, we examined glial fibrillary acidic protein concentrations in cerebrospinal fluid (cGFAP) as a marker of astrogliosis in SMA. Methods 58 adult patients and 21 children with genetically confirmed 5q‐associated SMA from four German motor neuron disease specialist care centers and 30 age‐ and sex‐matched controls were prospectively included in this study. cGFAP was measured and correlated to motor performance and disease severity. Additionally, we compared cGFAP with neurofilament light chain concentrations in cerebrospinal fluid (cNfL). Results cGFAP concentrations did not differ from controls but showed higher levels in more severely affected patients after adjustment for patients' age. Normalized cNfL values were associated with disease severity. Within 14 months of nusinersen treatment, cGFAP concentrations did not change, while cNfL decreased significantly. Interpretation cGFAP is not an outstanding biomarker in SMA, but might support the hypothesis that glial activation is involved in SMA pathology. Unlike previously suggested, cNfL may be a promising biomarker also in adult patients with SMA, which should be subject to further investigations.
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Affiliation(s)
- Maren Freigang
- Department of Neurology, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Petra Steinacker
- Department of Neurology, Universitätsklinikum Halle (Saale), Halle (Saale), Germany.,Department of Neurology, Ulm University, Ulm, Germany
| | | | | | - Alma Osmanovic
- Department of Neurology, Hannover Medical School, Hannover, Germany.,Essener Zentrum für Seltene Erkrankungen (EZSE), University Hospital Essen, Essen, Germany
| | - Susanne Petri
- Department of Neurology, Hannover Medical School, Hannover, Germany
| | - Jan C Koch
- Department of Neurology, University Medicine Göttingen, Göttingen, Germany
| | - Kevin Rostásy
- Department of Pediatric Neurology, Children's Hospital Datteln, University Witten/Herdecke, Datteln, Germany
| | - André Huss
- Department of Neurology, Ulm University, Ulm, Germany.,Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE) Ulm, Ulm, Germany
| | | | - Benedikt Winter
- Department of Pediatric Neurology, University Hospital Mannheim, Mannheim, Germany
| | - Björn Falkenburger
- Department of Neurology, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.,Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE) Dresden, Dresden, Germany
| | - Albert C Ludolph
- Department of Neurology, Ulm University, Ulm, Germany.,Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE) Ulm, Ulm, Germany
| | - Markus Otto
- Department of Neurology, Universitätsklinikum Halle (Saale), Halle (Saale), Germany
| | - Andreas Hermann
- Translational Neurodegeneration Section "Albrecht-Kossel", Department of Neurology, and Center for Transdisciplinary Neurosciences Rostock (CTNR), University Medical Center Rostock, University of Rostock, Rostock, Germany.,Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE) Rostock/Greifswald, Rostock, Germany
| | - René Günther
- Department of Neurology, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.,Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE) Dresden, Dresden, Germany
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