A novel monoclonal antibody reveals a conformational alteration shared by amyotrophic lateral sclerosis-linked SOD1 mutants

• Published in: Annals of neurology 2012-11, Vol.72 (5), p.739-749
• Main Authors: Fujisawa, Takao, Homma, Kengo, Yamaguchi, Namiko, Kadowaki, Hisae, Tsuburaya, Naomi, Naguro, Isao, Matsuzawa, Atsushi, Takeda, Kohsuke, Takahashi, Yuji, Goto, Jun, Tsuji, Shoji, Nishitoh, Hideki, Ichijo, Hidenori
• Format: Article
• Language: English
• Subjects: Amyotrophic lateral sclerosis; Amyotrophic Lateral Sclerosis - genetics; Amyotrophic Lateral Sclerosis - immunology; Animals; Antibodies, Monoclonal - metabolism; Biological and medical sciences; Cell Death; Cells, Cultured; Culture Media, Serum-Free - pharmacology; Disease Models, Animal; Gene Expression Regulation - genetics; Humans; Immunoprecipitation; Medical sciences; Membrane Proteins - metabolism; Mice; Mice, Inbred ICR; Mice, Transgenic; Motor Neurons - pathology; Motor Neurons - physiology; Multiple sclerosis and variants. Guillain barré syndrome and other inflammatory polyneuropathies. Leukoencephalitis; Mutation - genetics; Neurology; Protein Binding - genetics; Protein Conformation; Proteins; Spinal Cord - pathology; Superoxide Dismutase - genetics; Superoxide Dismutase-1; Transfection
• ISSN: 0364-5134; 1531-8249
• DOI: 10.1002/ana.23668

Objective: Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that is characterized by the selective loss of upper and lower motoneurons. Although >100 different Cu, Zn superoxide dismutase (SOD1) mutations have been identified in ALS patients, it remains controversial whether all of them are disease‐causative mutations. Therefore, it is necessary to develop molecular mechanism‐based diagnosis and treatment of ALS caused by SOD1 mutations. Methods: We previously reported that 3 pathogenic mutations of SOD1 cause chronic endoplasmic reticulum (ER) stress by inducing the binding of SOD1 to Derlin‐1, a component of the ER homeostatic machinery. Here, we systematically analyzed 132 SOD1 mutants and found that most have a constitutively exposed Derlin‐1–binding region (DBR) that is occluded in the wild‐type protein. To develop the novel molecular mechanism‐based antibody that can specifically recognize the aberrant structure of toxic SOD1 mutants, we generated the monoclonal antibody against the DBR. Results: MS785, a monoclonal antibody generated against the DBR, distinguished most ALS‐causative SOD1 mutants from both wild‐type and nontoxic mutants. Moreover, MS785 recognized endogenous SOD1 in B lymphocytes derived from 14 ALS patients carrying SOD1 mutations but not from 11 healthy controls. Interpretation: This is the first study to address the common property of all ALS‐causative SOD1 mutants. MS785 is the first molecular mechanism‐based antibody that was shown to be able to distinguish ALS‐linked toxic SOD1 mutants from both wild‐type and nontoxic mutants. MS785 may thus become an innovative tool for the diagnosis of ALS. ANN NEUROL 2012;72:739–749