CRISPR-Cas13bt3 Silences VEGFA in Retinal Cells

Cas13bt3 and sgRNA plasmids were delivered via adeno-associated virus (AAV) to human retinal organoids and VEGF-transgenic mouse models. This system effectively reduced VEGFA mRNA and protein expression with minimal off-target or collateral activity. The study explored multiplexed sgRNA delivery using single AAV vectors to assess whether multiple sgRNAs could enhance VEGFA knockdown efficiency; however, no significant increase in knockdown was observed.

Single-cell RNA sequencing and transcriptomic analysis showed that Cas13bt3, when combined with a targeting sgRNA, maintained high specificity, reducing VEGFA in retinal pigment epithelium (RPE) cells while limiting unintended gene expression impacts across other cell types.

The work, led by Satheesh Kumar and Guei-Sheung Liu from the Centre for Eye Research Australia and the University of Melbourne, was published yesterday in Proceedings of the National Academy of Sciences.