Artificial microRNA suppresses C9ORF72 variants and decreases toxic dipeptide repeat proteins in vivo

Area of Science:

• Neuroscience
• Genetics
• Molecular Biology

Background:

• Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are debilitating neurodegenerative diseases.
• The most common genetic cause is an expanded GGGGCC repeat in the C9ORF72 gene.
• This mutation leads to toxic C9ORF72 gene products, contributing to neuronal death.

Purpose of the Study:

• To investigate if suppressing C9ORF72 gene expression can mitigate its toxicity.
• To develop and test artificial microRNAs (amiRNAs) targeting the C9ORF72 gene.

Main Methods:

• Designed amiRNAs specifically targeting the human C9ORF72 gene.
• Utilized adeno-associated virus serotype 9 (AAV9) for gene delivery.
• Administered AAV9-mediated amiRNA to C9ORF72 transgenic mice.

Main Results:

• Demonstrated significant suppression of C9ORF72 mRNA and protein levels in the brain and spinal cord.
• Showed a reduction in toxic dipeptide repeat proteins produced by the expanded C9ORF72 repeat.
• Confirmed the efficacy of AAV9-mediated amiRNA in a mouse model.

Conclusions:

• AAV9-mediated delivery of amiRNAs targeting C9ORF72 is an effective strategy to reduce toxic gene products.
• This approach shows promise for treating C9ORF72-associated ALS and FTD.
• Further research may lead to novel therapeutic interventions for these conditions.