Muscleblind acts as a modifier of FUS toxicity by modulating stress granule dynamics and SMN localization

Area of Science:

• Neuroscience
• Genetics
• Molecular Biology

Background:

• Mutations in the fused in sarcoma (FUS) gene are linked to amyotrophic lateral sclerosis (ALS).
• The variability in ALS presentation suggests unknown genetic factors influencing disease progression.

Purpose of the Study:

• To identify novel genetic modifiers of FUS-mediated neurodegeneration.
• To investigate the role of muscleblind in FUS-induced ALS pathogenesis.

Main Methods:

• In vivo studies using mammalian neuronal and human iPSC-derived neurons.
• Genetic modulation of muscleblind and survival motor neuron (SMN) protein.
• Assessment of FUS protein localization, stress granule accumulation, dendritic morphology, and neuronal toxicity.

Main Results:

• Muscleblind was identified as a novel modifier of FUS-mediated neurodegeneration.
• Muscleblind regulates the cytoplasmic mislocalization of mutant FUS and its accumulation in stress granules.
• Genetic modulation of muscleblind restored SMN protein localization in FUS-mutant neurons.
• Upregulation of SMN suppressed FUS toxicity in various model systems.

Conclusions:

• Muscleblind acts as a dominant modifier of FUS-mediated neurodegeneration in ALS.
• Muscleblind influences FUS pathogenesis by regulating FUS protein localization and interacting with the SMN pathway.
• Targeting muscleblind or SMN may offer therapeutic strategies for FUS-ALS.