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RAB18 regulates extrahepatic siRNA-mediated gene silencing efficacy
Jiamiao Lu1, Jasper Lee1, Eric Yuan1
1Precision Biology, Amgen Inc., South San Francisco, CA 94080, USA.
Molecular Therapy. Nucleic Acids
|October 9, 2024
Summary
Researchers found that removing or reducing RAB18 protein significantly improves small interfering RNA (siRNA) gene silencing in various cells and in vivo. This discovery enhances siRNA therapy potential beyond the liver.
Area of Science:
- Molecular Biology
- RNA Therapeutics
- Cell Biology
Background:
- Small interfering RNAs (siRNAs) offer therapeutic potential for previously undruggable targets.
- siRNA delivery is limited by cell membrane impermeability, especially outside the liver.
- N-acetylgalactosamine (GalNAc) conjugation enhances liver-specific siRNA delivery.
Purpose of the Study:
- To investigate RAB18's role in siRNA delivery and efficacy.
- To enhance siRNA-mediated gene silencing in both hepatic and extrahepatic cells.
- To elucidate the mechanism of enhanced siRNA silencing.
Main Methods:
- Genome-wide pooled knockout screen to identify siRNA delivery modulators.
- RAB18 knockout and knockdown in cell lines and in vivo.
- Analysis of retrograde Golgi-ER transport and lipid droplet involvement.
Main Results:
- RAB18 knockout/knockdown significantly enhances siRNA-mediated gene silencing.
- This enhancement is observed in both liver and non-liver cells, as well as in vivo.
- Retrograde Golgi-ER transport and lipid droplets positively regulate siRNA silencing efficacy.
Conclusions:
- RAB18 is a key factor limiting siRNA efficacy, particularly for GalNAc-conjugated siRNAs.
- Targeting RAB18 offers a strategy to improve siRNA delivery and gene silencing across various cell types.
- Understanding the role of retrograde transport and lipid droplets can optimize siRNA-based therapies.
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