Development of carbazole-based molecules for inhibition of mutant hSOD1 protein aggregation in Amyotrophic Lateral Sclerosis

Abstract

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterised by the loss of upper and lower motor neurons. Cu/Zn superoxide dismutase (SOD1) is one of the genes associated with the familial form of the disease (fALS). The mechanism of neuron degeneration by SOD1 is not clear, it is hypothesised that there is a toxic gain of function in the protein which leads to the downstream effects. In the present study, carbazole-based molecules have been rationally designed and synthesised as potential inhibitors of mutant hSOD1 protein aggregation. SG-9 and SG-10 prevented the aggregation of all three purified mutant hSOD1 proteins. Transmission electron microscopy and dynamic light scattering experiments also revealed that co-incubation of SG-9 and SG-10 with mutant hSOD1 protein resulted in smaller and slender fibril forming. Molecules SG-9 and SG-10 did not display toxicity and prevented Neuro-2a cells expressing hSOD1 G85R protein from its associated cytotoxicity. SG-9 and SG-10 were also able to prevent the transfected cells from apoptosis and were also able to reduce ROS levels associated with hSOD1 G85R protein aggregation significantly. Therefore, novel carbazole derivatives SG-9 and SG-10 proved to be effective inhibitors of mutant hSOD1 protein aggregation and can be further utilised as lead molecules for the amelioration of mutant hSOD1 aggregation-associated ALS.