New insight!

RNA interference (RNAi) is a powerful mechanism for post-transcriptional regulation of selected target genes through complementary base pairing between small molecule regulatory RNAs and target mRNAs

Retinal gene therapy using RNA interference (RNAi) to silence target genes requires both efficacy and safety

However, several issues regarding the use of RNAi must be carefully considered

Image credit: https://doi.

Recently, researchers from Aarhus University in Denmark published a research article entitled "VEGFA-targeting miR-agshRNAs combine efficacy with specificity and safety for retinal gene therapy" in the journal Molecular Therapy: Nucleic Acids.

To improve efficacy and study safety, we prepared VEGFA-targeting agshRNAs and microRNA (MiRNA)-encapsulated agshRNAs (miR-agshRNAs), and inserted these RNAi effectors into Pol II/III-driven expression cassettes and Lentiviral vector (LV)

Compared to shRNAs, agshRNAs also resulted in a significantly smaller decrease in cell viability and reduced competition with endogenous miR21 processing

In mice, subretinal injection of LVs encoding tissue-specific miR-agshRNAs resulted in restricted retinal pigment epithelium (RPE) expression and significantly downregulated Vegfa expression in transduced RPE cells

LVs encoding U6-driven RNAi effectors produce broad sequence-dependent and sequence-independent effects

Image credit: https://doi.

In this study, we delivered an anti-VEGFA miR-agshRNA with LVs, supporting the notion that the miR-agshRNA system is easily adaptable to multiple targets, and that due to the small size of the expression cassette, other delivery systems may be equally useful, thereby expanding applicability of treatment

Taken together, this data demonstrates that agshRNAs, especially Pol II-driven miRagshRNAs, offer important advantages over classical shRNAs in terms of efficacy, high intrinsic specificity, safety, and versatility, making them ideal for future gene therapy-based therapies.

references

Sidsel Alsing et al.