Engineered CRISPR-Base Editors as a Permanent Treatment for Familial Dysautonomia

Area of Science:

• Genetics
• Molecular Biology
• Gene Therapy

Background:

• Familial Dysautonomia (FD) is a fatal neuropathy caused by an ELP1 gene mutation leading to exon skipping.
• Current treatments for FD are limited, necessitating novel therapeutic strategies.

Purpose of the Study:

• To develop and validate a precise base editor (BE) approach for correcting the specific ELP1 mutation causing FD.
• To assess the efficacy and safety of the BE strategy in cellular and animal models of FD.

Main Methods:

• Optimized Cas9 variants and guide RNAs (gRNAs) for high on-target editing efficiency in HEK293T cells.
• Developed an engineered dual intein-split system for in vivo delivery via adeno-associated virus (AAV).
• Evaluated the BE strategy in a humanized FD mouse model and induced pluripotent stem cell (iPSC)-derived neurons.

Main Results:

• Achieved up to 70% on-target editing of the ELP1 mutation, restoring correct exon 20 splicing.
• Demonstrated successful correction of splicing defects in the liver and brain of FD mice.
• Observed rescue of FD phenotype in iPSC-derived sympathetic neurons with minimal off-target effects.

Conclusions:

• The developed base editor strategy offers a highly precise and effective method for correcting the FD-causing ELP1 mutation and splicing defects.
• This foundational work paves the way for a transformative, permanent therapeutic solution for Familial Dysautonomia.