ALS-linked misfolded SOD1 species have divergent impacts on mitochondria.
Approximately 20 % of familial Amyotrophic Lateral Sclerosis (ALS) is caused by mutations in superoxide dismutase (SOD1), which leads to misfolding of the SOD1 protein, resulting in a toxic gain of function. Several conformation-restricted antibodies have been generated that specifically recognize misfolded SOD1 protein, and have been used as therapeutics in pre-clinical models. Misfolded SOD1 selectively associates with spinal cord mitochondria in SOD1 rodent models. Using the SOD1(G93A) rat model, we find that SOD1 conformational specific antibodies AMF7-63 and DSE2-3H1 labeled a fibrillar network concentrated in the anterior horn; while A5C3, B8H10, C4F6 and D3H5 labeled motor neurons as well as puncta in the neuropil. There is a time-dependent accumulation of misfolded SOD1 at the surface of spinal cord mitochondria with AMF7-63-labeled mitochondria having increased volume in contrast to a mitochondrial subset labeled with B8H10. In spinal cord homogenates and isolated mitochondria, AMF7-63, DSE2-3H1 and B8H10 detect misfolded SOD1 aggregates. SOD1 that lacks its metal cofactors has an increased affinity for naïve mitochondria and misfolded SOD1 antibodies B8H10 and DSE2-3H1 readily detect demetalated mutant and wild-type SOD1. Together, these data suggest that multiple non-native species of misfolded SOD1 may exist, some of which are associated with mitochondrial damage. Conformational antibodies are invaluable tools to identify and characterize the variation in misfolded SOD1 species with regards to biochemical characteristics and toxicity. This information is highly relevant to the further development of these reagents as therapeutics.
Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM) Université de Montréal, 900 rue Saint-Denis, Local R09.442, Montréal, QC, H2X 0A9, Canada.|Department of Biochemistry, Université de Montréal, Montréal, QC, H2X 0A9, Canada.
Sarah
S
Pickles
Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM) Université de Montréal, 900 rue Saint-Denis, Local R09.442, Montréal, QC, H2X 0A9, Canada.|Integrated Program in Neuroscience, McGill University, Montréal, QC, H3A 2B4, Canada.
Sabrina
S
Semmler
Department of Biochemistry, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.
Helen R
HR
Broom
Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM) Université de Montréal, 900 rue Saint-Denis, Local R09.442, Montréal, QC, H2X 0A9, Canada.
Laurie
L
Destroismaisons
Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM) Université de Montréal, 900 rue Saint-Denis, Local R09.442, Montréal, QC, H2X 0A9, Canada.|Department of Neurosciences, Université de Montréal, Montréal, QC, H2X 0A9, Canada.
Laurine
L
Legroux
Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM) Université de Montréal, 900 rue Saint-Denis, Local R09.442, Montréal, QC, H2X 0A9, Canada.|Department of Neurosciences, Université de Montréal, Montréal, QC, H2X 0A9, Canada.
Nathalie
N
Arbour
Department of Biochemistry, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.
Elizabeth
E
Meiering
Department of Medicine (Neurology), University of British Columbia and Vancouver Coastal Health Research Institute, Brain Research Centre, Vancouver, BC, V6T 2B5, Canada.
Neil R
NR
Cashman
Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM) Université de Montréal, 900 rue Saint-Denis, Local R09.442, Montréal, QC, H2X 0A9, Canada. c.vande.velde@umontreal.ca.|Department of Neurosciences, Université de Montréal, Montréal, QC, H2X 0A9, Canada. c.vande.velde@umontreal.ca.
Christine
C
Vande Velde
D000690:Amyotrophic Lateral Sclerosis / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D000906:Antibodies / Q000378:metabolism; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D008297:Male; D008670:Metals / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism* / Q000473:pathology; D066263:Protein Aggregation, Pathological / Q000378:metabolism / Q000473:pathology; D017510:Protein Folding; D057165:Proteostasis Deficiencies / Q000378:metabolism / Q000473:pathology; D055647:Rats, Transgenic; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013116:Spinal Cord / Q000378:metabolism / Q000473:pathology; D013482:Superoxide Dismutase / Q000378:metabolism*; D000072105:Superoxide Dismutase-1 / Q000235:genetics / Q000378:metabolism*
D000906:Antibodies; D008670:Metals; D011994:Recombinant Proteins; C000606290:SOD1 protein, human; C109415:SOD1 G93A protein; C000606292:Sod1 protein, rat; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1
Amyotrophic Lateral Sclerosis; Flow cytometry; Mitochondria; Superoxide dismutase