Mutant superoxide dismutase 1 overexpression in NSC-34 cells: Effect of trehalose on aggregation, TDP-43 localization and levels of co-expressed glycoproteins

Abstract

Protein inclusions rich in mutant Cu,Zn superoxide dismutase (SOD1) have been found in tissues from patients with familial amyotrophic lateral sclerosis (ALS). Here, the mouse motor neuron-like NSC-34 cell line transiently transfected with human SOD1 G93A fused to enhanced green fluorescent protein exhibited aggregates contrary to cells overexpressing wild-type human SOD1. The aggregates were immunoreactive for ubiquitin but not for the TAR DNA binding protein (TDP-43) that was found in the nucleus. These characteristics mimicked the pathology of mutant SOD1 associated familial ALS. Aggregate formation and mutant SOD1 detergent insolubility were significantly decreased in the presence of millimolar concentrations of trehalose possibly due to its capacity to induce autophagy or to its properties as chemical chaperone. Mutant SOD1, aggregated and non-aggregated, caused decreased levels of concomitantly expressed secretory (β-trace protein and erythropoietin) and plasma membrane (L1 cell adhesion molecule) glycoproteins, which were not due to their intracellular accumulation. These cells may be used to study mechanisms of pathogenesis associated with ALS and to test potential therapeutic compounds.