Identifying the molecular drivers of ALS-implicated missense mutations

Area of Science:

• Neuroscience
• Genetics
• Biophysics

Background:

• Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with motor and non-motor symptoms, including frontotemporal dementia.
• While 10% of ALS cases are familial, most are sporadic, with numerous gene mutations implicated but poorly understood at a molecular level.
• The relationship between genetic mutations and ALS phenotypes remains an area requiring further exploration.

Purpose of the Study:

• To curate an extensive database of missense mutations associated with ALS.
• To analyze the molecular effects of mutations in key ALS-associated genes (SOD1, FUS, TDP-43) using in silico biophysical tools.
• To compare the effects of pathogenic and non-pathogenic mutations to identify underlying molecular drivers of ALS.

Main Methods:

• Curated a comprehensive list of 1343 missense mutations across 111 genes from clinical literature.
• Utilized in silico biophysical tools to characterize changes in protein stability, interactions, localization, and function for SOD1, FUS, and TDP-43 mutations.
• Statistically compared pathogenic and non-pathogenic mutations to elucidate molecular mechanisms.

Main Results:

• Developed the most extensive missense mutation database for ALS to date, identifying a twofold increase in unique genes and a threefold increase in mutations compared to previous databases.
• Identified distinct molecular drivers: SOD1 mutations primarily reduced protein stability and dimer formation.
• Mutations in FUS and TDP-43 were located in disordered regions, suggesting different aggregate formation mechanisms.

Conclusions:

• The curated database provides a valuable resource for gene-specific analyses to advance the understanding of ALS.
• Distinct molecular insights were gained for SOD1, FUS, and TDP-43, offering new avenues for ALS research.
• Improved understanding of ALS molecular pathogenesis is crucial for developing effective treatment strategies.