<EM>IN VIVO</EM> ADENINE BASE EDITING-MEDIATED CORRECTION OF <EM>GALC</EM> GENE MUTATION AMELIORATES DISEASE PROGRESSION IN A MURINE MODEL OF KRABBE DISEASE

Krabbe disease (KD) is caused by mutations in the galactosylceramidase (GALC) gene, leading to impaired sphingolipid metabolism and sever demyelination. The twitcher (Galc^twi/twi) mouse harbors a G-to-A point mutation at codon 355 of Galc, generating a premature termination codon (PTC). In this study, we evaluated the therapeutic potential of adenine base editing (ABE) to correct this pathogenic mutation in vivo. The three ABE variants (ABEmax, ABE8eWQ, and ABE8e) were treated in mouse embryo fibroblasts. ABE8e, the highest efficacy of gene correction, were packaged into dual adeno-associated virus 9 vectors and administered via intracerebroventricular (ICV) injection to twitcher mice on postnatal day 1. Five weeks after ICV injection, base editing corrected PTC in approximately 0.5% of genomic DNA and 5% of Galc mRNA. ABE8e-treated mice showed significant improvements in body weight, brain weight, lifespan, and neurobehavioral performance. Molecular and biochemical analyses demonstrated increased Galc mRNA levels, restored GALC enzyme activity, and enhanced expression of myelin basic protein in the frontal cortex and corpus callosum. Moreover, transmission electron microscopy and magnetic resonance imaging showed preserved myelination and axonal integrity in the brain of ABE8e-treated twitcher mice. Collectively, these findings provide in vivo evidence that ABE can rescue GALC gene function and ameliorate disease progression in a model of KD.
Funding: This research was supported by the KFRM grant funded by the Korea government (21A0202L1), the NRF funded by the Ministry of Education (RS-2025-25437527), and KHIDI funded by the Ministry of Health & Welfare (HI22C1588, HI21C1314, RS-2022-KH129545, RS-2025-02215487).