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Ayers JI, Xu G, Lu Q, Dillon K, Fromholt S, Borchelt DR. Multiple Factors Influence the Incubation Period of ALS Prion-like Transmission in SOD1 Transgenic Mice. Viruses 2023; 15:1819. [PMID: 37766226 PMCID: PMC10534885 DOI: 10.3390/v15091819] [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: 07/24/2023] [Revised: 08/17/2023] [Accepted: 08/22/2023] [Indexed: 09/29/2023] Open
Abstract
Mutations in superoxide dismutase 1 (SOD1) that are associated with amyotrophic lateral sclerosis (ALS) cause its misfolding and aggregation. Prior studies have demonstrated that the misfolded conformation of ALS-SOD1 can template with naïve SOD1 "host proteins" to propagate, spread, and induce paralysis in SOD1 transgenic mice. These observations have advanced the argument that SOD1 is a host protein for an ALS conformer that is prion-like and experimentally transmissible. Here, we investigated the propagation of different isolates of G93A-SOD1 ALS conformers using a paradigm involving transmission to mice expressing human G85R-SOD1 fused to yellow fluorescent protein (G85R-SOD1:YFP). In these studies, we also utilized a newly developed line of mice in which the G85R-SOD1:YFP construct was flanked by loxp sites, allowing its temporal and spatial regulation. We used methods in which the G93A ALS conformers were injected into the sciatic nerve or hindlimb muscle of adult transgenic mice. We observed that the incubation period to paralysis varied significantly depending upon the source of inoculum containing misfolded G93A SOD1. Serial passage and selection produced stable isolates of G93A ALS conformers that exhibited a defined minimum incubation period of ~2.5 months when injected into the sciatic nerve of young adult mice. As expected, neuronal excision of the transgene in loxpG85R-SOD1:YFP mice blocked induction of paralysis by transmission of G93A ALS conformers. Our findings indicate that G93A ALS conformers capable of inducing disease require neuronal expression of a receptive host SOD1 protein for propagation, with a defined incubation period to paralysis.
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Affiliation(s)
- Jacob I. Ayers
- Institute for Neurodegenerative Disease, University of California, San Francisco, CA 94158, USA
| | - Guilian Xu
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL 32610, USA; (G.X.)
| | - Qing Lu
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL 32610, USA; (G.X.)
| | - Kristy Dillon
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL 32610, USA; (G.X.)
| | - Susan Fromholt
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL 32610, USA; (G.X.)
| | - David R. Borchelt
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL 32610, USA; (G.X.)
- SantaFe HealthCare Alzheimer’s Disease Research Center, McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
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Nordström U, Lang L, Ekhtiari Bidhendi E, Zetterström P, Oliveberg M, Danielsson J, Andersen PM, Marklund SL. Mutant SOD1 aggregates formed in vitro and in cultured cells are polymorphic and differ from those arising in the CNS. J Neurochem 2023; 164:77-93. [PMID: 36326589 PMCID: PMC10099669 DOI: 10.1111/jnc.15718] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 10/28/2022] [Accepted: 11/01/2022] [Indexed: 11/06/2022]
Abstract
Mutations in the human Superoxide dismutase 1 (hSOD1) gene are well-established cause of the motor neuron disease ALS. Patients and transgenic (Tg) ALS model mice carrying mutant variants develop hSOD1 aggregates in the CNS. We have identified two hSOD1 aggregate strains, which both transmit spreading template-directed aggregation and premature fatal paralysis when inoculated into adult transgenic mice. This prion-like spread of aggregation could be a primary disease mechanism in SOD1-induced ALS. Human SOD1 aggregation has been studied extensively both in cultured cells and under various conditions in vitro. To determine how the structure of aggregates formed in these model systems related to disease-associated aggregates in the CNS, we used a binary epitope-mapping assay to examine aggregates of hSOD1 variants G93A, G85R, A4V, D90A, and G127X formed in vitro, in four different cell lines and in the CNS of Tg mice. We found considerable variability between replicate sets of in vitro-generated aggregates. In contrast, there was a high similarity between replicates of a given hSOD1 mutant in a given cell line, but pronounced variations between different hSOD1 mutants and different cell lines in both structures and amounts of aggregates formed. The aggregates formed in vitro or in cultured cells did not replicate the aggregate strains that arise in the CNS. Our findings suggest that the distinct aggregate morphologies in the CNS could result from a micro-environment with stringent quality control combined with second-order selection by spreading ability. Explorations of pathogenesis and development of therapeutics should be conducted in models that replicate aggregate structures forming in the CNS.
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Affiliation(s)
- Ulrika Nordström
- Department of Clinical Science, Neurosciences, Umeå University, Umeå, Sweden
| | - Lisa Lang
- Department of Biochemistry and Biophysics, Arrhenius Laboratories of Natural Sciences, Stockholm University, Stockholm, Sweden
| | - Elaheh Ekhtiari Bidhendi
- Department of Clinical Science, Neurosciences, Umeå University, Umeå, Sweden.,Department of Medical Biosciences, Clinical Chemistry, Umeå University, Umeå, Sweden
| | - Per Zetterström
- Department of Medical Biosciences, Clinical Chemistry, Umeå University, Umeå, Sweden
| | - Mikael Oliveberg
- Department of Biochemistry and Biophysics, Arrhenius Laboratories of Natural Sciences, Stockholm University, Stockholm, Sweden
| | - Jens Danielsson
- Department of Biochemistry and Biophysics, Arrhenius Laboratories of Natural Sciences, Stockholm University, Stockholm, Sweden
| | - Peter M Andersen
- Department of Clinical Science, Neurosciences, Umeå University, Umeå, Sweden
| | - Stefan L Marklund
- Department of Medical Biosciences, Clinical Chemistry, Umeå University, Umeå, Sweden
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Forsberg KM, Graffmo KS, Stenvall E, Tabikh N, Marklund SL, Brännström T, Andersen PM. Widespread CNS pathology in amyotrophic lateral sclerosis homozygous for the D90A SOD1 mutation. Acta Neuropathol 2023; 145:13-28. [PMID: 36385230 PMCID: PMC9807479 DOI: 10.1007/s00401-022-02519-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 11/10/2022] [Accepted: 11/10/2022] [Indexed: 11/17/2022]
Abstract
Mutations in the gene encoding the ubiquitously expressed free radical scavenging enzyme superoxide dismutase-1 (SOD1) are found in 2-6% of amyotrophic lateral sclerosis patients. The most frequent SOD1 mutation worldwide is D90A. Amyotrophic lateral sclerosis caused by this mutation has some unusual features: the heredity is usually recessive, the phenotype is stereotypic with slowly evolving motor symptoms beginning in the legs and may also include sensory, autonomic, and urinary bladder involvement. Furthermore, the mutant protein resembles the wild type, with normal content and enzymatic activity in the central nervous system. Here, we report neuropathological findings in nine patients homozygous for the D90A mutation. All nine had numerous small granular inclusions immunoreactive for misfolded SOD1 in motor neurons and glial nuclei in the spinal cord and brainstem. In addition to degeneration of the corticospinal tracts, all patients had degeneration of the dorsal columns. We also found intense gliosis in circumscribed cortical areas of the frontal and temporal lobes and in the insula. In these areas and in adjacent white matter, there were SOD1 staining neuropil threads. A few SOD1-immunopositive cytoplasmic neuronal inclusions were observed in cortical areas, as were glial nuclear inclusions. As suggested by the symptoms and signs and earlier neurophysiological and imaging investigations, the histopathology in patients homozygous for the D90A SOD1 extends beyond the motor system to include cognitive and sensory cortical areas. However, even in the patients that had a symptomatic disease duration of more than 2 or 3 decades and lived into their 70s or 80s, there were no SOD1-inclusion pathology and no typical dysfunction (apart from the musculature) in non-nervous organs. Thus, only specific parts of the CNS seem to be vulnerable to toxicity provoked by homozygously expressed mutant SOD1.
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Affiliation(s)
- Karin M Forsberg
- Department of Clinical Sciences, Neurosciences, Umeå University, 90185, Umeå, Sweden.,Department of Medical Biosciences, Pathology, Umeå University, Umeå, Sweden
| | - Karin S Graffmo
- Department of Medical Biosciences, Pathology, Umeå University, Umeå, Sweden
| | - Erica Stenvall
- Department of Medical Biosciences, Pathology, Umeå University, Umeå, Sweden
| | - Naima Tabikh
- Department of Medical Biosciences, Pathology, Umeå University, Umeå, Sweden
| | - Stefan L Marklund
- Department of Medical Biosciences, Clinical Chemistry, Umeå University, Umeå, Sweden
| | - Thomas Brännström
- Department of Medical Biosciences, Pathology, Umeå University, Umeå, Sweden
| | - Peter M Andersen
- Department of Clinical Sciences, Neurosciences, Umeå University, 90185, Umeå, Sweden.
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Gosset P, Camu W, Raoul C, Mezghrani A. Prionoids in amyotrophic lateral sclerosis. Brain Commun 2022; 4:fcac145. [PMID: 35783556 PMCID: PMC9242622 DOI: 10.1093/braincomms/fcac145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 03/16/2022] [Accepted: 06/01/2022] [Indexed: 12/20/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is the third most frequent neurodegenerative disease after Alzheimer’s and Parkinson’s disease. ALS is characterized by the selective and progressive loss of motoneurons in the spinal cord, brainstem and cerebral cortex. Clinical manifestations typically occur in midlife and start with focal muscle weakness, followed by the rapid and progressive wasting of muscles and subsequent paralysis. As with other neurodegenerative diseases, the condition typically begins at an initial point and then spreads along neuroanatomical tracts. This feature of disease progression suggests the spreading of prion-like proteins called prionoids in the affected tissues, which is similar to the spread of prion observed in Creutzfeldt-Jakob disease. Intensive research over the last decade has proposed the ALS-causing gene products Cu/Zn superoxide dismutase 1, TAR DNA-binding protein of 43 kDa, and fused in sarcoma as very plausible prionoids contributing to the spread of the pathology. In this review, we will discuss the molecular and cellular mechanisms leading to the propagation of these prionoids in ALS.
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Affiliation(s)
- Philippe Gosset
- INM, Univ Montpellier, INSERM, CNRS, Montpellier 34095, France
| | - William Camu
- INM, Univ Montpellier, INSERM, CNRS, Montpellier 34095, France
| | - Cedric Raoul
- INM, Univ Montpellier, INSERM, CNRS, Montpellier 34095, France
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