Intracerebral lentiviral ABCD1 gene therapy in an early disease onset ALD mouse model

X-linked adrenoleukodystrophy (ALD) is a genetic disorder of the ABCD1 gene. We aimed to treat ALD via direct intracerebral injection of lentiviral ABCD1 (LV.ABCD1). Lentiviral vectors (LVs) were injected into the brain of wild type mice to access toxicities and biodistribution. Confocal microscopy illustrated supraphysiological ABCD1 expression surrounding the injection sites, and LVs were also detected in the opposite site of the unilaterally injected brain. In multi-site bilateral injections (4, 6, 8, and 9 sites), LV.ABCD1 transduced most brain regions including the cerebellum. Investigation of neuronal loss, astrogliosis and microglia activation did not detect abnormality. For efficacy evaluation, a novel ALD knockout (KO) mouse model was established by deleting exons 3 to 9 of the ABCD1 gene based on CRISPR/Cas9 gene editing. The KO mice showed behavioral deficit in open-field test (OFT) and reduced locomotor activities in rotarod test at 6 and 7 months of age, respectively. We treated 3-month-old KO mice with bilateral LV.ABCD1 injections into the external capsule and thalamus. ABCD1 expression was detected 15 days later, and the impaired motor ability was gradually alleviated. Our studies established an early onset ALD model and illustrated neurological improvement after LV.ABCD1 intracerebral injection without immunopathological toxicity.