Discovery and characterization of novel inhibitors against ALS-related SOD1(A4V) aggregation through screening of a chemical library using Differerential Scanning Fluorimetry (DSF)

Abstract

Cu/Zn Superoxide Dismutase 1 (SOD1) is a 32-kDa cytosolic dimeric metalloenzyme that neutralizes superoxide anions into harmless oxygen and hydrogen peroxide. Mutations in SOD1 are associated with ALS, a disease causing motor neuron atrophy and subsequent mortality. These mutations exert their harmful effects through a gain of function mechanism, rather than loss of function. Despite extensive research, the specific mechanism causing selective motor neuron death still remains unclear. A defining feature of ALS pathogenesis is protein misfolding and aggregation, evidenced by ubiquitinated protein inclusions containing SOD1 in motor neurons. This work aims to identify compounds countering SOD1(A4V) misfolding and aggregation, potentially aiding ALS treatment. The approach employed is drug repurposing and in vitro screening of a 1280 pharmacologically active compounds library, LOPAC(R). Using Differential Scanning Fluorimetry Technique (DSF), compounds were tested for their impact on SOD1(A4V) thermal stability. Screening revealed one compound raising protein-ligand Tm by 7{degrees}C, eight inducing a higher second Tm, suggesting stabilzation effect, and five reducing Tm up to 18{degrees}C, suggesting possible interactions or non-specific binding.