Characterising Stargardt Disease Mutations for Splice Intervention Therapeutics

Project Aim

This project aims to find a treatment for Stargardt disease (STGD1), a genetic eye condition. Stargardt disease caused by mutations in the ABCA4 gene.

In this project, the researchers plan to study the specific genetic changes in ABCA4 that lead to the disease and try to develop a type of treatment called splice-switching antisense oligonucleotides (SS-AONs). These SS-AONs are like temporary “modifiers” for the gene and can be used to fix the gene’s behaviour at the level of its messengers (mRNA) without making permanent changes to the DNA. This can be safer than other gene therapies.

One advantage of SS-AONs is that they are easy to deliver into the eye through injections, and they can be made in large quantities. They are also small and pure, which makes them effective. Other treatments using SS-AONs have shown promise in genetic disorders, which makes this approach very exciting for potentially treating Stargardt disease.

Project Summary

We will utilise STGD1 patient skin cells from the Western Australian Retinal Disease (WARD) Study biobank to identify the defects associated with specific ABAC4 mutations. This work will uncover the mechanisms associated with particular ABCA4 mutations, enhancing our ability to provide accurate genetic diagnosis for STGD1 and improving access to clinical trials. Additionally, this work will identify mutations that can be treated with a new class of drugs, known as ‘splice-switching antisense oligonucleotides’ (SSAONs).

We will develop new SS-AONs tailored for treating amenable mutations present in our STGD1 cohort. STGD1 patient skin cells will be converted into iPSC and retinal cells in the laboratory. SSAON drugs will then be tested in our STGD1 patient-derived retinal cells to identify suitable candidates for future clinical trials.

Expected outcomes

Identification and characterisation of ABCA4 variants in STGD1 patients to provide valuable insights into the underlying mechanisms of the disease. This will be accomplished through advanced molecular techniques and comprehensive analysis of aberrant splicing patterns.
The assessment of the effectiveness of SS-AONs, which will be conducted via in vitro functional assays using iPSC and its derived RPE cells. Quantitative assessment of corrected splicing events and restoration of functional ABCA4 protein expression, evaluated through robust techniques such as RT-PCR, Western blotting and immunostaining, will serve as key indicators of the success of SS-AONs as a promising personalised treatment approach.