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Updated: Jun 24, 2025
Real-Time Fluorescent Measurement of Synaptic Functions in Models of Amyotrophic Lateral Sclerosis
Published on: July 16, 2021
M6A reduction relieves FUS-associated ALS granules
Gaia Di Timoteo1, Andrea Giuliani1, Adriano Setti1
1Department of Biology and Biotechnology Charles Darwin, Sapienza University of Rome, Rome, 00185, Italy.
Abstract:
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease due to gradual motoneurons (MN) degeneration. Among the processes associated to ALS pathogenesis, there is the formation of cytoplasmic inclusions produced by aggregation of mutant proteins, among which the RNA binding protein FUS. Here we show that, in neuronal cells and in iPSC-derived MN expressing mutant FUS, such inclusions are significantly reduced in number and dissolve faster when the RNA m6A content is diminished. Interestingly, stress granules formed in ALS conditions showed a distinctive transcriptome with respect to control cells, which reverted to similar to control after m6A downregulation. Notably, cells expressing mutant FUS were characterized by higher m6A levels suggesting a possible link between m6A homeostasis and pathological aggregates. Finally, we show that FUS inclusions are reduced also in patient-derived fibroblasts treated with STM-2457, an inhibitor of METTL3 activity, paving the way for its possible use for counteracting aggregate formation in ALS.
Insights
Reducing RNA N6-methyladenosine (m6A) levels diminishes pathological FUS protein inclusions in amyotrophic lateral sclerosis (ALS) models. This suggests targeting m6A homeostasis may offer a novel therapeutic strategy for ALS.
Area of Science:
- Neuroscience
- Molecular Biology
- Genetics
Background:
- Amyotrophic lateral sclerosis (ALS) involves motoneuron degeneration and the formation of cytoplasmic inclusions from mutant proteins like FUS.
- RNA N6-methyladenosine (m6A) modification plays a role in cellular processes, but its specific involvement in ALS pathogenesis is not fully understood.
Purpose of the Study:
- To investigate the role of m6A content in the formation and dissolution of FUS-induced inclusions in ALS.
- To explore the potential of targeting m6A pathways for therapeutic intervention in ALS.
Main Methods:
- Utilized neuronal cells and induced pluripotent stem cell (iPSC)-derived motoneurons expressing mutant FUS.
- Manipulated m6A RNA content and analyzed the number and dissolution rate of FUS inclusions.
- Examined the transcriptome of stress granules in ALS conditions.
- Treated patient-derived fibroblasts with METTL3 inhibitor STM-2457.
Main Results:
- Diminishing m6A content significantly reduced the number and accelerated the dissolution of FUS inclusions in neuronal cells and iPSC-derived motoneurons.
- ALS conditions altered the transcriptome of stress granules, which normalized after m6A downregulation.
- Cells expressing mutant FUS exhibited higher m6A levels, indicating a potential link between m6A homeostasis and aggregate formation.
- Treatment with METTL3 inhibitor STM-2457 reduced FUS inclusions in patient-derived fibroblasts.
Conclusions:
- Reduced m6A levels effectively counteract pathological FUS aggregate formation in ALS cellular models.
- m6A homeostasis is implicated in ALS pathogenesis, suggesting it as a potential therapeutic target.
- METTL3 inhibition shows promise for reducing FUS inclusions, offering a potential therapeutic avenue for ALS treatment.
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