Wet age-related macular degeneration (AMD) can be controlled with regular eye injections, but the cost and discomfort of the procedure is a burden on both patients and the healthcare system. 

New research led by Satheesh Kumar and Associate Professor Guei-Sheung (Rick) Liu from CERA and the University of Melbourne has found a gene therapy technique with the potential to end the need for regular injections. 

They have for the first time used an RNA editing tool – known as CRISPR Cas13 – to suppress the production of vascular endothelial growth factor (VEGF) in human retinal cells. VEGF is a protein that causes abnormal leaky blood vessels to grow in the retina at the back of the eye – and is the key driver of vision loss in wet AMD and diabetic retinopathy. 

“Our study shows the potential of RNA editing to develop gene therapies that offer an alternative treatment to the invasive, frequent eye injections that are currently used to treat wet macular degeneration and diabetic eye disease,’’ says Associate Professor Liu. 

Changing instructions 

While DNA provides the instructions for cells to function, RNA carries out these instructions by transmitting their message to cells. 

The experiment targeted the mRNA sequence that instructs cells to produce VEGF. 

It delivered the RNA editing tool via an adeno-associated virus vector and was tested on a mouse model and human retinal cells derived from stem cells. 

It showed that the viral vector was effective in delivering the treatment to retinal cells and produced a significant reduction in VEGF, and a slowing of disease progression in the mouse model. 

The research was performed alongside scientists from the University of Sydney, Children’s Medical Research Institute, University of Western Australia and Zhongshan City People’s Hospital, China, and published in Proceedings of the National Academy of Sciences in 2024. 

“Although this research is in the early discovery stages and requires further development before transitioning to clinical trials, we envision that RNA editing could become a viable alternative to invasive and costly eye injections that have become a fact of life for many people living with wet macular degeneration or diabetic eye disease.’’ 

Associate Professor Liu’s research is supported by the Lions Ride for Sight and the CERA Foundation. 

This story was originally published in Share our vision: Annual Review 2024.